Adaptive Central Force Optimization Algorithm Based on the Stability Analysis
Directory of Open Access Journals (Sweden)
Weiyi Qian
2015-01-01
Full Text Available In order to enhance the convergence capability of the central force optimization (CFO algorithm, an adaptive central force optimization (ACFO algorithm is presented by introducing an adaptive weight and defining an adaptive gravitational constant. The adaptive weight and gravitational constant are selected based on the stability theory of discrete time-varying dynamic systems. The convergence capability of ACFO algorithm is compared with the other improved CFO algorithm and evolutionary-based algorithm using 23 unimodal and multimodal benchmark functions. Experiments results show that ACFO substantially enhances the performance of CFO in terms of global optimality and solution accuracy.
UWB Array Design Using Variable Zo Technology and Central Force Optimization
Formato, Richard A
2011-01-01
This note applies Variable Zo technology to the design of an Ultra Wideband (UWB) Yagi-Uda array optimized using Central Force Optimization. Variable Zo is a novel and proprietary approach to antenna design and optimization that treats the feed system characteristic impedance, Zo, as a design variable instead of a fixed design parameter as is traditionally done. Variable Zo is applicable to any antenna design or optimization methodology, and using it will generally produce better antenna designs across any user-specified set of performance objectives.
2015-03-26
Applications ( VBA ) & LINGO Optimization Software interface that allows changing each exogenous variable of the models in a flexible way. The...Median Model ................................................................ 44 3.7 Generating VBA & Lingo Combination as a Useful Tool...Finally, we define changes to the models in Chapter 2 to make them applicable for our problem. All of these are then implemented using VBA (Visual Basic
Optimal central bank transparency
van der Cruijsen, C.A.B.; Eijffinger, S.C.W.; Hoogduin, L.
2008-01-01
Should central banks increase their degree of transparency any further? We show that there is likely to be an optimal intermediate degree of central bank transparency. Up to this optimum more transparency is desirable: it improves the quality of private sector inflation forecasts. But beyond the opt
Optimal central bank transparency
van der Cruijsen, C.A.B.; Eijffinger, S.C.W.; Hoogduin, L.H.
2010-01-01
Should central banks increase their degree of transparency any further? We show that there is likely to be an optimal intermediate degree of central bank transparency. Up to this optimum more transparency is desirable: it improves the quality of private sector inflation forecasts. But beyond the opt
CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY
Energy Technology Data Exchange (ETDEWEB)
BERGMAN, T. B.; STEFANSKI, L. D.; SEELEY, P. N.; ZINSLI, L. C.; CUSACK, L. J.
2012-09-19
THE CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY WAS CONDUCTED TO DEVELOP AN OPTIMAL SEQUENCE OF REMEDIATION ACTIVITIES IMPLEMENTING THE CERCLA DECISION ON THE CENTRAL PLATEAU. THE STUDY DEFINES A SEQUENCE OF ACTIVITIES THAT RESULT IN AN EFFECTIVE USE OF RESOURCES FROM A STRATEGIC PERSPECTIVE WHEN CONSIDERING EQUIPMENT PROCUREMENT AND STAGING, WORKFORCE MOBILIZATION/DEMOBILIZATION, WORKFORCE LEVELING, WORKFORCE SKILL-MIX, AND OTHER REMEDIATION/DISPOSITION PROJECT EXECUTION PARAMETERS.
Simulating central forces in the classroom
Aguirregabiria, Juan M
2015-01-01
We describe the easy to customize and extend open source Java program Central force workbench that can be used in the classroom to simulate the motion of a particle (or a two-body system) under central forces. It may be useful to illustrate problems in which the analytical solution is not available as well as to help students to grasp a more intuitive understanding of the main features of this kind of problem and to realize the exceptional nature of the particular case of Newtonian (and harmonic) forces. We also include some suggestions on how to use the program as a pedagogical tool.
School Administration: Optimal Ratio of Centralization to Decentralization.
Kapto, A. E.
1990-01-01
Compares advantages and disadvantages of centralized and decentralized control in Soviet public schools. Recognizes that centralization concentrates the forces, funds, and available resources necessary for maximum achievement. Suggests that decentralization of administration can be optimized by delegating rights, duties, and responsibilities to…
FORCE OPTIMIZATION OF GRASPING BY ROBOTIC HANDS
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
It is important for robotic hands to obtain optimal grasping performance in the meanwhile balancing external forces and maintaining grasp stability.The problem of force optimization of grasping is solved in the space of joint torques.A measure of grasping performance is presented to protect joint actuators from working in heavy payloads.The joint torques are calculated for the optimal performance under the frictional constraints and the physical limits of motor outputs.By formulating the grasping forces into the explicit function of joint torques, the frictional constraints imposed on the grasping forces are transformed into the constraints on joint torques.Without further simplification, the nonlinear frictional constraints can be simply handled in the process of optimization.Two numerical examples demonstrate the simplicity and effectiveness of the approach.
Relativistic Newtonian Dynamics under a central force
Friedman, Yaakov
2016-10-01
Planck's formula and General Relativity indicate that potential energy influences spacetime. Using Einstein's Equivalence Principle and an extension of his Clock Hypothesis, an explicit description of this influence is derived. We present a new relativity model by incorporating the influence of the potential energy on spacetime in Newton's dynamics for motion under a central force. This model extends the model used by Friedman and Steiner (EPL, 113 (2016) 39001) to obtain the exact precession of Mercury without curving spacetime. We also present a solution of this model for a hydrogen-like atom, which explains the reason for a probabilistic description.
Skov, Søren Nielsen; Røpcke, Diana Mathilde; Ilkjær, Christine; Rasmussen, Jonas; Tjørnild, Marcell Juan; Jimenez, Jorge H; Yoganathan, Ajit P; Nygaard, Hans; Nielsen, Sten Lyager; Jensen, Morten Olgaard
2016-03-21
Limited knowledge exists about the forces acting on mitral valve annuloplasty repair devices. The aim of this study was to develop a new mitral annular force transducer to measure the forces acting on clinically used mitral valve annuloplasty devices. The design of an X-shaped transducer in the present study was optimized for simultaneous in- and out-of-plane force measurements. Each arm was mounted with strain gauges on four circumferential elements to measure out-of-plane forces, and the central parts of the X-arms were mounted with two strain gauges to measure in-plane forces. A dedicated calibration setup was developed to calibrate isolated forces with tension and compression for in- and out-of-plane measurements. With this setup, it was possible with linear equations to isolate and distinguish measured forces between the two planes and minimize transducer arm crosstalk. An in-vitro test was performed to verify the crosstalk elimination method and the assumptions behind it. The force transducer was implanted and evaluated in an 80kg porcine in-vivo model. Following crosstalk elimination, in-plane systolic force accumulation was found to be in average 4.0±0.1N and the out-of-plane annular segments experienced an average force of 1.4±0.4N. Directions of the systolic out-of-plane forces indicated movements towards a saddle shaped annulus, and the transducer was able to measure independent directional forces in individual annular segments. Further measurements with the new transducer coupled with clinical annuloplasty rings will provide a detailed insight into the biomechanical dynamics of these devices.
Optimization of the blank holder force in cup drawing
Gharib, H.; A.S. Wifi,; M. Younan; Nassef, A
2006-01-01
Purpose: Develop an optimization strategy for the cup drawing process in order to produce a defect free deepdrawn cup.Design/methodology/approach: An optimization strategy for the blank holder force (BHF) scheme is proposedwhich searches for the BHF scheme that minimizes the maximum punch force and avoids process limits. Thisstrategy is applied to the linearly varying BHF scheme and compared to the constant BHF.Findings: The optimized linear BHF scheme resulted in an improved cup forming when...
Optimal dimensional synthesis of force feedback lower arm exoskeletons
Ünal, Ramazan; Unal, Ramazan; Patoğlu, Volkan; Patoglu, Volkan
2008-01-01
This paper presents multi-criteria design optimization of parallel mechanism based force feedback exoskeletons for human forearm and wrist. The optimized devices are aimed to be employed as a high fidelity haptic interfaces. Multiple design objectives are discussed and classified for the devices and the optimization problem to study the trade-offs between these criteria is formulated. Dimensional syntheses are performed for optimal global kinematic and dynamic performance, utilizing a Pareto ...
OPTIMAL CONVERGENCE RATE OF THE LANDAU EQUATION WITH FRICTIONAL FORCE
Institute of Scientific and Technical Information of China (English)
Liu Shuangqian; Liu Hongxia
2012-01-01
The Cauchy problem of the Landau equation with frictional force is investigated.Based on Fourier analysis and nonlinear energy estimates,the optimal convergence rate to the steady state is obtained under some conditions on initial data.
Optimizing feed force for turned parts through the Taguchi technique
Indian Academy of Sciences (India)
Hari Singh; Pradeep Kumar
2006-12-01
The objective of the paper is to obtain an optimal setting of turning process parameters (cutting speed, feed rate and depth of cut) resulting in an optimal value of the feed force when machining EN24 steel with TiC-coated tungsten-carbide inserts. The effects of the selected turning process parameters on feed force and the subsequent optimal settings of the parameters have been accomplished using Taguchi’s parameter design approach. The results indicate that the selected process parameters signiﬁcantly affect the selected machining characteristics. The results are conﬁrmed by further experiments.
Optimal Release Control of Companion Satellite System Using Electromagnetic Forces
Institute of Scientific and Technical Information of China (English)
Zengwen Xu,Peng Shi; Yushan Zhao∗
2015-01-01
Electromagnetic forces generated by the inter⁃action of component satellites can be used to release companion satellites. Optimal release trajectories for companion satellite system using inter⁃electromagnetic forces were investigated. Firstly, nonlinear relative motion dynamic equations of a two⁃craft electromagnetic companion satellite system were derived in spatial polar coordinates. Then principles of electromagnetic satellite formation flying were introduced. Secondly, the characteristics of the electromagnetic companion satellites release were analyzed and optimal release trajectories of companion satellites using electromagnetic forces were obtained using Gauss pseudospectral method. Three performance criteria were chosen as minimum time, minimum acceleration of the separation distance and minimum control acceleration. Finally, three release examples including expansion along separation distance, rotation in orbital plane and stable formation reconfiguration were given to demonstrate the feasibility of this method. Results indicated that the release trajectories can converge to optimal solutions effectively and the concept of release companion satellites using electromagnetic forces is practicable.
An Optimization-Based Impedance Approach for Robot Force Regulation with Prescribed Force Limits
Directory of Open Access Journals (Sweden)
R. de J. Portillo-Vélez
2015-01-01
Full Text Available An optimization based approach for the regulation of excessive or insufficient forces at the end-effector level is introduced. The objective is to minimize the interaction force error at the robot end effector, while constraining undesired interaction forces. To that end, a dynamic optimization problem (DOP is formulated considering a dynamic robot impedance model. Penalty functions are considered in the DOP to handle the constraints on the interaction force. The optimization problem is online solved through the gradient flow approach. Convergence properties are presented and the stability is drawn when the force limits are considered in the analysis. The effectiveness of our proposal is validated via experimental results for a robotic grasping task.
Centralized Stochastic Optimal Control of Complex Systems
Energy Technology Data Exchange (ETDEWEB)
Malikopoulos, Andreas [ORNL
2015-01-01
In this paper we address the problem of online optimization of the supervisory power management control in parallel hybrid electric vehicles (HEVs). We model HEV operation as a controlled Markov chain using the long-run expected average cost per unit time criterion, and we show that the control policy yielding the Pareto optimal solution minimizes the average cost criterion online. The effectiveness of the proposed solution is validated through simulation and compared to the solution derived with dynamic programming using the average cost criterion.
Optimized molecular force field for sulfur hexafluoride simulations.
Olivet, Aurelio; Vega, Lourdes F
2007-04-14
An optimized molecular force field for sulfur hexafluoride (SF6) simulations is presented in this work. The new force field for SF6 contains two parts: a Lennard-Jones potential that deals with F-F intermolecular interactions and the second term dealing with the intramolecular forces. In this second part the flexibility of the molecule is explicitly considered by 6 harmonic stretch terms, modeling the S-F chemical bonds, and 12 harmonic bending terms, modeling the F-S-F angular deformations. The parameters of the new force field have been obtained by a multivariable optimization procedure, whose main feature is the simultaneous fitting of all force field parameters, using as reference data several equilibrium properties (vapor pressure, saturated liquid density, and surface tension) and shear viscosity. The new force field clearly improves the description of the phase envelope and the rest of the properties as compared to previous simulations for a rigid model for the same molecule [A. Olivet et al., J. Chem. Phys. 123, 194508 (2005)]. Results for the optimized force field concerning the vapor-liquid coexistence curve, several thermodynamics states at the homogeneous gas and liquid region, and transport coefficients of SF6 are in good agreement with available experimental data.
Optimal plane change by low aerodynamic forces
Vinh, Nguyen X.; Ma, Der-Ming
1990-01-01
This paper presents the exact dimensionless equations of motion and the necessary conditions for the computation of the optimal trajectories of a hypervelocity vehicle flying through a nonrotating spherical planetary atmosphere. It is shown that there are two types of maneuvers with nearly identical plane change. In the hard maneuver, the vehicle is pulled down to low altitude for aerodyamic plane change before exit at the prescribed final speed. In the slow maneuver which is described in detail in this paper, the vehicle remains in orbital flight with a small incremental plane change during each passage through the perigee. This maneuver requires several revolutions, and the technique for computation is similar to that in the problem of contraction of orbit.
Optimizing Long-Term Capital Planning for Special Operations Forces
2015-06-01
portfolio. The goal of this thesis is to improve the LRCPT by developing proof-of- principle optimization models for long-range capital planning. We...Operations Forces (SOF) capability gaps in the future. This thesis presents three proof-of- principle long-range capital planning models designed to...RECOMMENDATIONS We formulated and analyzed three proof-of- principle optimization models for capital planning: the Binary Knapsack (BK) model, the
Optimal plane changes using third-body forces.
Villac, B F; Scheeres, D J
2004-05-01
The fuel optimality of third-body driven plane changes (i.e., plane changes performed by using third-body forces) over one-impulse transfers is investigated numerically and analytically. In particular, the range of third-body driven plane changes that are realizable is shown to be restricted and one impulse must be used in the uncovered regions. However, when third-body driven plane changes are realizable, it is shown that they are always optimal above a certain critical value (about 40 degrees ) that depends on the initial condition. Contour plots of optimal DeltaV values to perform a desired plane changes are given.
Final Report of the Simulation Optimization Task Force
Rimoldi, A; Dell'Acqua, A; Froidevaux, D; Gianotti, F; Guyot, C; Hinchliffe, I; Jakobs, K; Marshall, Z; Nisati, A; Quarrie, D; Unal, G; Young, C
2009-01-01
This is the final report of the ATLAS Simulation Optimization Task Force, established in June of 2007. This note justifies the selected Geant4 version, physics list, and range cuts to be used by the default ATLAS simulation for initial data taking and beyond. The current status of several projects, including detector description, simulation validation, studies of additional Geant4 parameters, and cavern background, are reported.
Many-body central force potentials for tungsten
Bonny, G.; Terentyev, D.; Bakaev, A.; Grigorev, P.; Van Neck, D.
2014-07-01
Tungsten and tungsten-based alloys are the primary candidate materials for plasma facing components in fusion reactors. The exposure to high-energy radiation, however, severely degrades the performance and lifetime limits of the in-vessel components. In an effort to better understand the mechanisms driving the materials' degradation at the atomic level, large-scale atomistic simulations are performed to complement experimental investigations. At the core of such simulations lies the interatomic potential, on which all subsequent results hinge. In this work we review 19 central force many-body potentials and benchmark their performance against experiments and density functional theory (DFT) calculations. As basic features we consider the relative lattice stability, elastic constants and point-defect properties. In addition, we also investigate extended lattice defects, namely: free surfaces, symmetric tilt grain boundaries, the 1/2{1 1 0} and 1/2 {1 1 2} stacking fault energy profiles and the 1/2 screw dislocation core. We also provide the Peierls stress for the 1/2 edge and screw dislocations as well as the glide path of the latter at zero Kelvin. The presented results serve as an initial guide and reference list for both the modelling of atomically-driven phenomena in bcc tungsten, and the further development of its potentials.
Optimizing Armed Forces Capabilities for Hybrid Warfare – New Challenge for Slovak Armed Forces
Directory of Open Access Journals (Sweden)
Peter PINDJÁK
2015-09-01
Full Text Available The paper deals with the optimization of military capabilities of the Slovak Armed Forces for conducting operations in a hybrid conflict, which represents one of the possible scenarios of irregular warfare. Whereas in the regular warfare adversaries intend to eliminate the centers of gravity of each other, most often command and control structures, in irregular conflicts, the center of gravity shifts towards the will and cognitive perception of the target population. Hybrid warfare comprises a thoroughly planned combination of conventional military approaches and kinetic operations with subversive, irregular activities, including information and cyber operations. These efforts are often accompanied by intensified activities of intelligence services, special operation forces, and even mercenary and other paramilitary groups. The development of irregular warfare capabilities within the Slovak Armed Forces will require a progressive transformation process that may turn the armed forces into a modern and adaptable element of power, capable of deployment in national and international crisis management operations.
Theory of cellwise optimization for solar central receiver system
Lipps, F. W.
1985-05-01
Cost effective optimization of the solar central receiver system is primarily concerned with the distribution of heliostats in the collector field, including the boundaries of the field. The cellwise optimization procedure determines the optimum cell usage and heliostat spacing parameters for each cell in the collector field. Spacing parameters determine the heliostat density and neighborhood structure uniformly in each cell. Consequently, the cellwise approach ignores heliostat mismatch at cell boundaries. Ignoring the cell boundary problem permits an easy solution for the optimum in terms of appropriately defined annual average data. Insolation, receiver interception, shading and blocking, cosine effects, and the cost parameters combine to control the optimum. Many trade offs are represented. Outputs include the receiver flux density distribution for design time, coefficients for an actual layout, the optimum boundary and various performance and cost estimates for the optimum field. It is also possible to optimize receiver size and tower height by a repeated application of the field optimization procedure.
Optimized third-order force-gradient symplectic algorithms
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
With the natural splitting of a Hamiltonian system into kinetic energy and potential energy,we construct two new optimal thirdorder force-gradient symplectic algorithms in each of which the norm of fourth-order truncation errors is minimized.They are both not explicitly superior to their no-optimal counterparts in the numerical stability and the topology structure-preserving,but they are in the accuracy of energy on classical problems and in one of the energy eigenvalues for one-dimensional time-independent Schrdinger equations.In particular,they are much better than the optimal third-order non-gradient symplectic method.They also have an advantage over the fourth-order non-gradient symplectic integrator.
Katz Centrality of Markovian Temporal Networks: Analysis and Optimization
Ogura, Masaki
2016-01-01
Identifying important nodes in complex networks is a fundamental problem in network analysis. Although a plethora of measures has been proposed to identify important nodes in static (i.e., time-invariant) networks, there is a lack of tools in the context of temporal networks (i.e., networks whose connectivity dynamically changes over time). The aim of this paper is to propose a system-theoretic approach for identifying important nodes in temporal networks. In this direction, we first propose a generalization of the popular Katz centrality measure to the family of Markovian temporal networks using tools from the theory of Markov jump linear systems. We then show that Katz centrality in Markovian temporal networks can be efficiently computed using linear programming. Finally, we propose a convex program for optimizing the Katz centrality of a given node by tuning the weights of the temporal network in a cost-efficient manner. Numerical simulations illustrate the effectiveness of the obtained results.
Energy Technology Data Exchange (ETDEWEB)
Fix, Stuart; Richman, Russell [Department of Architectural Science, Faculty of Engineering, Architecture and Science, Ryerson University (Canada)], email: sfix@ryerson.ca, email: richman@ryerson.ca
2011-07-01
With the depletion of energy resources and the rising concerns about the environment, building designers are shifting towards green building designs. However since no design optimization for an entire building exists, a significant degree of uncertainty is involved in design decisions. The aim of this paper is to present the brute force optimization process which is a method removing the uncertainty from green building designs. This method relies on the selection of optimization criteria and then several simulations are performed. A demonstration pilot was carried out in Toronto and over one million design permutations were conducted. Results showed that parameters such as total building area, window performance and infiltration level are the most important to the lifetime energy consumption of a building. This study pointed out the important parameters to optimize in order to reduce a building's energy consumption.
Optimizing significance testing of astronomical forcing in cyclostratigraphy
Kemp, David B.
2016-12-01
The recognition of astronomically forced (Milankovitch) climate cycles in geological archives marked a major advance in Earth science, revealing a heartbeat within the climate system of general importance and key utility. Power spectral analysis is the primary tool used to facilitate identification of astronomical cycles in stratigraphic data, but commonly employed methods for testing the statistical significance of relatively high narrow-band variance of potential astronomical origin in spectra have been criticized for inadequately balancing the respective probabilities of type I (false positive) and type II (false negative) errors. This has led to suggestions that the importance of astronomical forcing in Earth history is overstated. It can be readily demonstrated, however, that the imperfect nature of the stratigraphic record and the quasiperiodicity of astronomical cycles sets an upper limit on the attainable significance of astronomical signals. Optimized significance testing is that which minimizes the combined probability of type I and type II errors. Numerical simulations of stratigraphically preserved astronomical signals suggest that optimum significance levels at which to reject a null hypothesis of no astronomical forcing are between 0.01 and 0.001 (i.e., 99-99.9% confidence level). This is lower than commonly employed in the literature (90-99% confidence levels). Nevertheless, in consonance with the emergent view from other scientific disciplines, fixed-value null hypothesis significance testing of power spectra is implicitly ill suited to demonstrating astronomical forcing, and the use of spectral analysis remains a difficult and subjective endeavor in the absence of additional supporting evidence.
Kazakhstan: A Key Economic Driving Force of Central Asia
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
@@ Located strategically in the center of Eurasia, the Republic of Kazakhstan has been the largest country in terms of its territory, and also one of the most important economy and dynamic transport hub with abundant resources in Central Asia.
Eichelberger, Tamara D; Bilodeau, Martin
2007-09-01
The aim of this study was to compare the extent of central fatigue in the first dorsal interosseous (FDI) muscle of healthy adults in low, moderate and high-force submaximal contractions. Nine healthy adults completed four experimental sessions where index finger abduction force was recorded during voluntary contractions and in response to brief trains (five pulses at 100 Hz) of electrical stimulation. The ability to maximally activate FDI under volition, or voluntary activation, and its change with sustained activity (central fatigue) was assessed using the twitch interpolation technique. The fatigue tasks consisted of continuous isometric index finger abduction contractions held until exhaustion at four target force levels: 30%, 45%, 60% and 75% of the maximal voluntary contraction. The main finding was the presence of central fatigue for the 30% task, but not for the three other fatigue tasks. The extent of central fatigue was also associated with changes in a measure reflecting the status of peripheral structures/mechanisms. It appears that central fatigue contributed to task failure for the lowest force fatigue task (30%), but not for the other (higher) contraction intensities.
Nishikawa, Shin; Hirashima, Naohide; Tanaka, Masahiko
2014-09-01
The development and function of the central nervous system (CNS) are realized through interactions between many neurons. To investigate cellular and molecular mechanisms of the development and function of the CNS, it is thus crucial to be able to manipulate the gene expression of single neurons in a complex cell population. We recently developed a technique for gene silencing by introducing small interfering RNA into single neurons in primary CNS cultures using single-cell electroporation. However, we had not succeeded in forced gene expression by introducing expression plasmids using single-cell electroporation. In the present study, we optimized the experimental conditions to enable the forced expression of green fluorescent protein (GFP) in cultured cerebellar Purkinje neurons using single-cell electroporation. We succeeded in strong GFP expression in Purkinje neurons by increasing the inside diameter of micropipettes or by making the size of the original plasmid smaller by digestion and cyclizing it by ligation. Strong GFP expression in Purkinje neurons electroporated under the optimal conditions continued to be observed for more than 25 days after electroporation. Thus, this technique could be used for forced gene expression in single neurons to investigate cellular and molecular mechanisms of the development, function, and disease of the CNS.
Efficient retrieval of landscape Hessian: forced optimal covariance adaptive learning.
Shir, Ofer M; Roslund, Jonathan; Whitley, Darrell; Rabitz, Herschel
2014-06-01
Knowledge of the Hessian matrix at the landscape optimum of a controlled physical observable offers valuable information about the system robustness to control noise. The Hessian can also assist in physical landscape characterization, which is of particular interest in quantum system control experiments. The recently developed landscape theoretical analysis motivated the compilation of an automated method to learn the Hessian matrix about the global optimum without derivative measurements from noisy data. The current study introduces the forced optimal covariance adaptive learning (FOCAL) technique for this purpose. FOCAL relies on the covariance matrix adaptation evolution strategy (CMA-ES) that exploits covariance information amongst the control variables by means of principal component analysis. The FOCAL technique is designed to operate with experimental optimization, generally involving continuous high-dimensional search landscapes (≳30) with large Hessian condition numbers (≳10^{4}). This paper introduces the theoretical foundations of the inverse relationship between the covariance learned by the evolution strategy and the actual Hessian matrix of the landscape. FOCAL is presented and demonstrated to retrieve the Hessian matrix with high fidelity on both model landscapes and quantum control experiments, which are observed to possess nonseparable, nonquadratic search landscapes. The recovered Hessian forms were corroborated by physical knowledge of the systems. The implications of FOCAL extend beyond the investigated studies to potentially cover other physically motivated multivariate landscapes.
Directory of Open Access Journals (Sweden)
Shivakumar H
2008-01-01
Full Text Available A central composite design was employed to produce microcapsules of propranolol hydrochloride by o/o emulsion solvent evaporation technique using a mixture of cellulose acetate butyrate as coat material and span-80 as an emulsifier. The effect of formulation variables namely levels of cellulose acetate butyrate (X 1 and percentage of Span-80 (X 2 on encapsulation efficiency (Y 1 , drug release at the end of 1.5 h (Y 2 , 4 h (Y 3 , 8 h (Y 4 , 14 h (Y 5 , and 24 h (Y 6 were evaluated using the F test. Mathematical models containing only the significant terms were generated for each response parameter using multiple linear regression analysis and analysis of variance. Both the formulation variables exerted a significant influence (P < 0.05 on Y 1 whereas the cellulose acetate butyrate level emerged as the lone factor which significantly influenced the other response parameters. Numerical optimization using desirability approach was employed to develop an optimized formulation by setting constraints on the dependent and independent variables. The experimental values of Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , and Y 6 for the optimized formulation was found to be 92.86±1.56% w/w, 29.58±1.22%, 48.56±2.56%, 60.85±2.35%, 76.23±3.16% and 95.12±2.41%, respectively which were in close agreement with those predicted by the mathematical models. The drug release from microcapsules followed first order kinetics and was characterized by Higuchi diffusion model. The optimized microcapsule formulation developed was found to comply with the USP drug release test-1 for extended release propranolol hydrochloride capsules.
Optimized optical clearing method for imaging central nervous system
Yu, Tingting; Qi, Yisong; Gong, Hui; Luo, Qingming; Zhu, Dan
2015-03-01
The development of various optical clearing methods provides a great potential for imaging entire central nervous system by combining with multiple-labelling and microscopic imaging techniques. These methods had made certain clearing contributions with respective weaknesses, including tissue deformation, fluorescence quenching, execution complexity and antibody penetration limitation that makes immunostaining of tissue blocks difficult. The passive clarity technique (PACT) bypasses those problems and clears the samples with simple implementation, excellent transparency with fine fluorescence retention, but the passive tissue clearing method needs too long time. In this study, we not only accelerate the clearing speed of brain blocks but also preserve GFP fluorescence well by screening an optimal clearing temperature. The selection of proper temperature will make PACT more applicable, which evidently broaden the application range of this method.
Central Nervous System Multiparameter Optimization Desirability: Application in Drug Discovery.
Wager, Travis T; Hou, Xinjun; Verhoest, Patrick R; Villalobos, Anabella
2016-06-15
Significant progress has been made in prospectively designing molecules using the central nervous system multiparameter optimization (CNS MPO) desirability tool, as evidenced by the analysis reported herein of a second wave of drug candidates that originated after the development and implementation of this tool. This simple-to-use design algorithm has expanded design space for CNS candidates and has further demonstrated the advantages of utilizing a flexible, multiparameter approach in drug discovery rather than individual parameters and hard cutoffs of physicochemical properties. The CNS MPO tool has helped to increase the percentage of compounds nominated for clinical development that exhibit alignment of ADME attributes, cross the blood-brain barrier, and reside in lower-risk safety space (low ClogP and high TPSA). The use of this tool has played a role in reducing the number of compounds submitted to exploratory toxicity studies and increasing the survival of our drug candidates through regulatory toxicology into First in Human studies. Overall, the CNS MPO algorithm has helped to improve the prioritization of design ideas and the quality of the compounds nominated for clinical development.
Possible contributory role of the central histaminergic system in the forced swimming model.
Noguchi, S; Fukuda, Y; Inukai, T
1992-05-01
Forced swimming is considered to bring about a depressive or despair state in experimental animals, usually manifested as immobility. Levoprotiline (CAS 76496-68-9), a new antidepressant, clearly reduced the duration of immobility in the forced swimming model in mice. As levoprotiline does not inhibit noradrenaline or serotonin reuptake, this effect did not seem to have been brought about through central monoaminergic systems. Histamine and tele-methylhistamine levels, the main metabolite of histamine in the cerebral cortex, were found to be significantly increased in the forced swimming model. Since the only significant known effect of levoprotiline on the neurotransmitter system is its histamine H1 receptor antagonism, a possible contribution of the central histaminergic system to the forced swimming model is proposed. The action of mepyramine, a histamine H1 receptor antagonist in reducing the duration of immobility seemed to support this proposition. It should be noted that antihistaminergic properties are shared by many antidepressant drugs.
Optimal Discrete PTO Force Point Absorber Wave Energy Converters in Regular Waves
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik C.
2013-01-01
the conventional fluid power systems suffer of poor efficiency. Therefore discrete fluid power force systems have been proposed. Limited research has, however, been conducted with focus on choosing the discrete force levels and force profiles for a discrete PTO system for WECs. This paper is to support the design...... of discrete force systems for PTO, by focusing on how to choose the optimal PTO force levels and force profile when seeking to increase energy harvesting. The work concerns point absorber WECs and utilises a simple float model based on linear wave theory. Utilising the principle of superposition...
Global optimization of parameters in the reactive force field ReaxFF for SiOH.
Larsson, Henrik R; van Duin, Adri C T; Hartke, Bernd
2013-09-30
We have used unbiased global optimization to fit a reactive force field to a given set of reference data. Specifically, we have employed genetic algorithms (GA) to fit ReaxFF to SiOH data, using an in-house GA code that is parallelized across reference data items via the message-passing interface (MPI). Details of GA tuning turn-ed out to be far less important for global optimization efficiency than using suitable ranges within which the parameters are varied. To establish these ranges, either prior knowledge can be used or successive stages of GA optimizations, each building upon the best parameter vectors and ranges found in the previous stage. We have finally arrive-ed at optimized force fields with smaller error measures than those published previously. Hence, this optimization approach will contribute to converting force-field fitting from a specialist task to an everyday commodity, even for the more difficult case of reactive force fields.
Optimal tracking of a sEMG based force model for a prosthetic hand.
Potluri, Chandrasekhar; Anugolu, Madhavi; Yihun, Yimesker; Jensen, Alex; Chiu, Steve; Schoen, Marco P; Naidu, D Subbaram
2011-01-01
This paper presents a surface electromyographic (sEMG)-based, optimal control strategy for a prosthetic hand. System Identification (SI) is used to obtain the dynamic relation between the sEMG and the corresponding skeletal muscle force. The input sEMG signal is preprocessed using a Half-Gaussian filter and fed to a fusion-based Multiple Input Single Output (MISO) skeletal muscle force model. This MISO system model provides the estimated finger forces to be produced as input to the prosthetic hand. Optimal tracking method has been applied to track the estimated force profile of the Fusion based sEMG-force model. The simulation results show good agreement between reference force profile and the actual force.
Institute of Scientific and Technical Information of China (English)
TENG Fei; ZHANG Wanxi; LIANG Jicai; GAO Song
2015-01-01
Most of the existing studies use constant force to reduce springback while researching stretch force. However, variable stretch force can reduce springback more efficiently. The current research on springback prediction in stretch bending forming mainly focuses on artificial neural networks combined with the finite element simulation. There is a lack of springback prediction by support vector regression (SVR). In this paper, SVR is applied to predict springback inthe three-dimensional stretch bending forming process,and variable stretch force trajectory is optimized. Six parameters of variable stretch force trajectory are chosen as the input parameters of the SVR model. Sixty experiments generated by design of experiments (DOE) are carried out to train and test the SVR model. The experimental results confirm that the accuracy of the SVR model is higher than that of artificial neural networks. Based on this model, an optimization algorithm of variable stretch force trajectory using particle swarm optimization (PSO) is proposed. The springback amount is used as the objective function. Changes of local thickness are applied as the criterion of forming constraints. The objection and constraints are formulated by response surface models. The precision of response surface models is examined. Six different stretch force trajectories are employed to certify springback reduction in the optimum stretch force trajectory, which can efficiently reduce springback. This research proposes a new method of springback prediction using SVR and optimizes variable stretch force trajectory to reduce springback.
Optimal control of an influenza model with seasonal forcing and age-dependent transmission rates.
Lee, Jeehyun; Kim, Jungeun; Kwon, Hee-Dae
2013-01-21
This study considers an optimal intervention strategy for influenza outbreaks. Variations in the SEIAR model are considered to include seasonal forcing and age structure, and control strategies include vaccination, antiviral treatment, and social distancing such as school closures. We formulate an optimal control problem by minimizing the incidence of influenza outbreaks while considering intervention costs. We examine the effects of delays in vaccine production, seasonal forcing, and age-dependent transmission rates on the optimal control and suggest some optimal strategies through numerical simulations.
Kolossváry, István
2012-01-01
We propose a new way of looking at global optimization of off-lattice protein models. We present a dual optimization concept of predicting optimal sequences as well as optimal folds. We validate the utility of the recently introduced hidden-force Monte Carlo optimization algorithm by finding significantly lower energy folds for minimalist protein models than previously reported. Further, we also find the protein sequence that yields the lowest energy fold amongst all sequences for a given chain length and residue mixture. In particular, for protein models with a binary sequence, we show that the sequence-optimized folds form more compact cores than the lowest energy folds of the historically fixed, Fibonacci-series sequences of chain lengths of 13, 21, 34, 55, and 89. We emphasize that while the protein model we used is minimalist, the methodology is applicable to detailed protein models, and sequence optimization may yield novel folds and aid de novo protein design.
Evaluation of the force applied by the tongue and lip on the maxillary central incisor tooth
Valentim,Amanda Freitas; Furlan,Renata Maria Moreira Moraes; Perilo,Tatiana Vargas de Castro; Berbert, Monalise Costa Batista; Motta, Andréa Rodrigues; Casas, Estevam Barbosa de Las
2014-01-01
PURPOSE: To describe the development and testing of a system that measures forces exerted by the tongue and upper lip on a tooth during rest and during swallowing. METHODS: Twenty-eight subjects, aged 19-31 years (mean: 23.2 years) were submitted to measurement of forces exerted by the upper lip and tongue on the maxillary right central incisor tooth. Flexiforce resistive sensors were fixed on the labial and lingual surfaces of the tooth. They were connected to an amplifier circuit and a data...
Ye, Chang-Qing; Ma, Guang-Tong; Liu, Kun; Wang, Jia-Su
2017-01-01
The superconducting levitation realized by immersing the high-temperature superconductors (HTSs) into nonuniform magnetic field is deemed promising in a wide range of industrial applications such as maglev transportation and kinetic energy storage. Using a well-established electromagnetic model to mathematically describe the HTS, we have developed an efficient scheme that is capable of intelligently and globally optimizing the permanent magnet guideway (PMG) with single or multiple HTSs levitated above for the maglev transportation applications. With maximizing the levitation force as the principal objective, we optimized the dimensions of a Halbach-derived PMG to observe how the field, current and force distribute inside the HTSs when the optimized situation is achieved. Using a pristine PMG as a reference, we have analyzed the critical issues for enhancing the levitation force through comparing the field, current and force distributions between the optimized and pristine PMGs. It was also found that the optimized dimensions of the PMG are highly dependent upon the levitated HTS. Moreover, the guidance force is not always contradictory to the levitation force and may also be enhanced when the levitation force is prescribed to be the principle objective, depending on the configuration of levitation system and lateral displacement.
Ye, Chang-Qing; Ma, Guang-Tong; Liu, Kun; Wang, Jia-Su
2016-08-01
The superconducting levitation realized by immersing the high-temperature superconductors (HTSs) into nonuniform magnetic field is deemed promising in a wide range of industrial applications such as maglev transportation and kinetic energy storage. Using a well-established electromagnetic model to mathematically describe the HTS, we have developed an efficient scheme that is capable of intelligently and globally optimizing the permanent magnet guideway (PMG) with single or multiple HTSs levitated above for the maglev transportation applications. With maximizing the levitation force as the principal objective, we optimized the dimensions of a Halbach-derived PMG to observe how the field, current and force distribute inside the HTSs when the optimized situation is achieved. Using a pristine PMG as a reference, we have analyzed the critical issues for enhancing the levitation force through comparing the field, current and force distributions between the optimized and pristine PMGs. It was also found that the optimized dimensions of the PMG are highly dependent upon the levitated HTS. Moreover, the guidance force is not always contradictory to the levitation force and may also be enhanced when the levitation force is prescribed to be the principle objective, depending on the configuration of levitation system and lateral displacement.
Central-force decomposition of spline-based modified embedded atom method potential
Winczewski, S.; Dziedzic, J.; Rybicki, J.
2016-10-01
Central-force decompositions are fundamental to the calculation of stress fields in atomic systems by means of Hardy stress. We derive expressions for a central-force decomposition of the spline-based modified embedded atom method (s-MEAM) potential. The expressions are subsequently simplified to a form that can be readily used in molecular-dynamics simulations, enabling the calculation of the spatial distribution of stress in systems treated with this novel class of empirical potentials. We briefly discuss the properties of the obtained decomposition and highlight further computational techniques that can be expected to benefit from the results of this work. To demonstrate the practicability of the derived expressions, we apply them to calculate stress fields due to an edge dislocation in bcc Mo, comparing their predictions to those of linear elasticity theory.
Contingency Forces in the Year 2020 Optimizing Joint Warfighting
1993-04-22
Operation Desert One: (Operation Rice Bowl): August 1980 Iranian hostage rescue mission. 3. Operation Urgent Fury: 25 October 1983 Invasion of Grenada...already on casualty lists, and U.S. citizens and U.S. industrial facilities were being held hostage for 1xiternational leverage. Chemical weapons had been...operations units, Naval units, or commands such as the Joint Special Operations Ccawand-- JSOC ) is just as appropriate for contingency forces. Such
Thermoeconomic optimization of small size central air conditioner
Energy Technology Data Exchange (ETDEWEB)
Zhang, G.Q.; Wang, L.; Liu, L.; Wang, Z. [Hunan University (China). College of Civil Engineering
2004-03-01
The application of thermoeconomic optimization design in an air-conditioning system is important in achieving economical life cycle cost. Previous work on thermoeconomic optimization mainly focused on directly calculating exergy input into the system. However, it is usually difficult to do so because of the uncertainty of input power of fan on the air side of the heat-exchanger and that of pump in the system. This paper introduces a new concept that exergy input into the system can be substituted for the sum of exergy destruction and exergy output from the system according to conservation of exergy. Although it is also difficult for a large-scale system to calculate exergy destruction, it is feasible to do so for a small-scale system, for instance, villa air conditioner (VAC). In order to perform thermoeconomic optimization, a program is firstly developed to evaluate the thermodynamic property of HFC 134a on the basis of Martin-Hou state equation. Authors develop thermodynamic and thermoeconomic objective functions based on second law and thermoeconomic analysis of VAC system. Two optimization results are obtained. The design of VAC only aimed at decreasing the energy consumption is not comprehensive. Life cycle cost at thermoeconomic optimization is lower than that at thermodynamic optimization. (author)
Muscle synergies may improve optimization prediction of knee contact forces during walking.
Walter, Jonathan P; Kinney, Allison L; Banks, Scott A; D'Lima, Darryl D; Besier, Thor F; Lloyd, David G; Fregly, Benjamin J
2014-02-01
The ability to predict patient-specific joint contact and muscle forces accurately could improve the treatment of walking-related disorders. Muscle synergy analysis, which decomposes a large number of muscle electromyographic (EMG) signals into a small number of synergy control signals, could reduce the dimensionality and thus redundancy of the muscle and contact force prediction process. This study investigated whether use of subject-specific synergy controls can improve optimization prediction of knee contact forces during walking. To generate the predictions, we performed mixed dynamic muscle force optimizations (i.e., inverse skeletal dynamics with forward muscle activation and contraction dynamics) using data collected from a subject implanted with a force-measuring knee replacement. Twelve optimization problems (three cases with four subcases each) that minimized the sum of squares of muscle excitations were formulated to investigate how synergy controls affect knee contact force predictions. The three cases were: (1) Calibrate+Match where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously matched, (2) Precalibrate+Predict where experimental knee contact forces were predicted using precalibrated muscle model parameters values from the first case, and (3) Calibrate+Predict where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously predicted, all while matching inverse dynamic loads at the hip, knee, and ankle. The four subcases used either 44 independent controls or five synergy controls with and without EMG shape tracking. For the Calibrate+Match case, all four subcases closely reproduced the measured medial and lateral knee contact forces (R2 ≥ 0.94, root-mean-square (RMS) error force prediction. For the Precalibrate+Predict and Calibrate+Predict cases, synergy controls yielded better contact force predictions (0.61 force predictions improved when
Force-based optimization of pseudopotentials for non-equilibrium configurations
Brock, Casey N.; Paikoff, Brandon C.; Md Sallih, Muhammad I.; Tackett, Alan R.; Walker, D. Greg
2016-04-01
We have used a multi-objective genetic algorithm to optimize pseudopotentials for force accuracy and computational efficiency. Force accuracy is determined by comparing interatomic forces generated using the pseudopotentials and forces generated using the full-potential linearized augmented-plane wave method. This force-based optimization approach is motivated by applications where interatomic forces are important, including material interfaces, crystal defects, and molecular dynamics. Our method generates Pareto sets of optimized pseudopotentials containing various compromises between accuracy and efficiency. We have tested our method for LiF, Si0.5Ge0.5, and Mo and compared the performance of our pseudopotentials with pseudopotentials available from the ABINIT library. We show that the optimization can generate pseudopotentials with comparable accuracy (in terms of force matching and equation of state) to pseudopotentials in the literature while sometimes significantly improving computational efficiency. For example, we generated pseudopotentials for one system tested that reduced computational work by 71% without loss of accuracy. These results suggest our method can be used to generate pseudopotentials on demand that are tuned for a user's specific application, affording gains in computational efficiency.
Optimizing the US Navy’s Combat Logistics Force
2008-01-01
of four basic commodities for each client ship, navigational issues such as slow passages through canals , and the possibility of several client ships... canal or restricted passage). This Figure 2. Worldwide sea route network. This particular network is for a case with 13 battle group customers...shuttle capacity. For exploratory optimization to merely assemble and fil - ter scenario data for errors—preparatory exercises we admit take much more of
Force control of a tri-layer conducting polymer actuator using optimized fuzzy logic control
Itik, Mehmet; Sabetghadam, Mohammadreza; Alici, Gursel
2014-12-01
Conducting polymers actuators (CPAs) are potential candidates for replacing conventional actuators in various fields, such as robotics and biomedical engineering, due to their advantageous properties, which includes their low cost, light weight, low actuation voltage and biocompatibility. As these actuators are very suitable for use in micro-nano manipulation and in injection devices in which the magnitude of the force applied to the target is of crucial importance, the force generated by CPAs needs to be accurately controlled. In this paper, a fuzzy logic (FL) controller with a Mamdani inference system is designed to control the blocking force of a trilayer CPA with polypyrrole electrodes, which operates in air. The particle swarm optimization (PSO) method is employed to optimize the controller’s membership function parameters and therefore enhance the performance of the FL controller. An adaptive neuro-fuzzy inference system model, which can capture the nonlinear dynamics of the actuator, is utilized in the optimization process. The optimized Mamdani FL controller is then implemented on the CPA experimentally, and its performance is compared with a non-optimized fuzzy controller as well as with those obtained from a conventional PID controller. The results presented indicate that the blocking force at the tip of the CPA can be effectively controlled by the optimized FL controller, which shows excellent transient and steady state characteristics but increases the control voltage compared to the non-optimized fuzzy controllers.
Morrow, Melissa M; Rankin, Jeffery W; Neptune, Richard R; Kaufman, Kenton R
2014-11-07
The primary purpose of this study was to compare static and dynamic optimization muscle force and work predictions during the push phase of wheelchair propulsion. A secondary purpose was to compare the differences in predicted shoulder and elbow kinetics and kinematics and handrim forces. The forward dynamics simulation minimized differences between simulated and experimental data (obtained from 10 manual wheelchair users) and muscle co-contraction. For direct comparison between models, the shoulder and elbow muscle moment arms and net joint moments from the dynamic optimization were used as inputs into the static optimization routine. RMS errors between model predictions were calculated to quantify model agreement. There was a wide range of individual muscle force agreement that spanned from poor (26.4% Fmax error in the middle deltoid) to good (6.4% Fmax error in the anterior deltoid) in the prime movers of the shoulder. The predicted muscle forces from the static optimization were sufficient to create the appropriate motion and joint moments at the shoulder for the push phase of wheelchair propulsion, but showed deviations in the elbow moment, pronation-supination motion and hand rim forces. These results suggest the static approach does not produce results similar enough to be a replacement for forward dynamics simulations, and care should be taken in choosing the appropriate method for a specific task and set of constraints. Dynamic optimization modeling approaches may be required for motions that are greatly influenced by muscle activation dynamics or that require significant co-contraction.
The cost of leg forces in bipedal locomotion: a simple optimization study.
Directory of Open Access Journals (Sweden)
John R Rebula
Full Text Available Simple optimization models show that bipedal locomotion may largely be governed by the mechanical work performed by the legs, minimization of which can automatically discover walking and running gaits. Work minimization can reproduce broad aspects of human ground reaction forces, such as a double-peaked profile for walking and a single peak for running, but the predicted peaks are unrealistically high and impulsive compared to the much smoother forces produced by humans. The smoothness might be explained better by a cost for the force rather than work produced by the legs, but it is unclear what features of force might be most relevant. We therefore tested a generalized force cost that can penalize force amplitude or its n-th time derivative, raised to the p-th power (or p-norm, across a variety of combinations for n and p. A simple model shows that this generalized force cost only produces smoother, human-like forces if it penalizes the rate rather than amplitude of force production, and only in combination with a work cost. Such a combined objective reproduces the characteristic profiles of human walking (R² = 0.96 and running (R² = 0.92, more so than minimization of either work or force amplitude alone (R² = -0.79 and R² = 0.22, respectively, for walking. Humans might find it preferable to avoid rapid force production, which may be mechanically and physiologically costly.
The cost of leg forces in bipedal locomotion: a simple optimization study.
Rebula, John R; Kuo, Arthur D
2015-01-01
Simple optimization models show that bipedal locomotion may largely be governed by the mechanical work performed by the legs, minimization of which can automatically discover walking and running gaits. Work minimization can reproduce broad aspects of human ground reaction forces, such as a double-peaked profile for walking and a single peak for running, but the predicted peaks are unrealistically high and impulsive compared to the much smoother forces produced by humans. The smoothness might be explained better by a cost for the force rather than work produced by the legs, but it is unclear what features of force might be most relevant. We therefore tested a generalized force cost that can penalize force amplitude or its n-th time derivative, raised to the p-th power (or p-norm), across a variety of combinations for n and p. A simple model shows that this generalized force cost only produces smoother, human-like forces if it penalizes the rate rather than amplitude of force production, and only in combination with a work cost. Such a combined objective reproduces the characteristic profiles of human walking (R² = 0.96) and running (R² = 0.92), more so than minimization of either work or force amplitude alone (R² = -0.79 and R² = 0.22, respectively, for walking). Humans might find it preferable to avoid rapid force production, which may be mechanically and physiologically costly.
Accurate integral equation theory for the central force model of liquid water and ionic solutions
Ichiye, Toshiko; Haymet, A. D. J.
1988-10-01
The atom-atom pair correlation functions and thermodynamics of the central force model of water, introduced by Lemberg, Stillinger, and Rahman, have been calculated accurately by an integral equation method which incorporates two new developments. First, a rapid new scheme has been used to solve the Ornstein-Zernike equation. This scheme combines the renormalization methods of Allnatt, and Rossky and Friedman with an extension of the trigonometric basis-set solution of Labik and co-workers. Second, by adding approximate ``bridge'' functions to the hypernetted-chain (HNC) integral equation, we have obtained predictions for liquid water in which the hydrogen bond length and number are in good agreement with ``exact'' computer simulations of the same model force laws. In addition, for dilute ionic solutions, the ion-oxygen and ion-hydrogen coordination numbers display both the physically correct stoichiometry and good agreement with earlier simulations. These results represent a measurable improvement over both a previous HNC solution of the central force model and the ex-RISM integral equation solutions for the TIPS and other rigid molecule models of water.
An actuator line model simulation with optimal body force projection length scales
Martinez-Tossas, Luis; Churchfield, Matthew J.; Meneveau, Charles
2016-11-01
In recent work (Martínez-Tossas et al. "Optimal smoothing length scale for actuator line models of wind turbine blades", preprint), an optimal body force projection length-scale for an actuator line model has been obtained. This optimization is based on 2-D aerodynamics and is done by comparing an analytical solution of inviscid linearized flow over a Gaussian body force to the potential flow solution of flow over a Joukowski airfoil. The optimization provides a non-dimensional optimal scale ɛ / c for different Joukowski airfoils, where ɛ is the width of the Gaussian kernel and c is the chord. A Gaussian kernel with different widths in the chord and thickness directions can further reduce the error. The 2-D theory developed is extended by simulating a full scale rotor using the optimal body force projection length scales. Using these values, the tip losses are captured by the LES and thus, no additional explicit tip-loss correction is needed for the actuator line model. The simulation with the optimal values provides excellent agreement with Blade Element Momentum Theory. This research is supported by the National Science Foundation (Grant OISE-1243482, the WINDINSPIRE project).
Research on Optimal Development Pattern of Yunnan Central Economic Region
Institute of Scientific and Technical Information of China (English)
Diego Salmero; Suman Rana
2012-01-01
By the case study on the Urban Agglomeration Plan of Yunnan Central Economic Region (YCER), which is jointly made by Chinese and Swiss scholars, with the adoption of GIS and traditional urban planning methods, this paper uses multiple scenarios to analyze four development models of "Scattered Yunnan," "Regional Yunnan," "Metropolitan Yunnan" and "Network Yunnan." It also explores the relatively rational scenarios for the future development of YCER, i.e., up to 2030, the development model of YCER will be "Regional," and after 2030 it will be "Network." In this way, YCER will be developed stably and methodically, and finally achieve the unification of ecological safety, intensified energy and resources, as well as prosperous economy.
Morrow, Melissa M.; Rankin, Jeffery W.; Neptune, Richard R.; Kaufman, Kenton R.
2014-01-01
The primary purpose of this study was to compare static and dynamic optimization muscle force and work predictions during the push phase of wheelchair propulsion. A secondary purpose was to compare the differences in predicted shoulder and elbow kinetics and kinematics and handrim forces. The forward dynamics simulation minimized differences between simulated and experimental data (obtained from 10 manual wheelchair users) and muscle co-contraction. For direct comparison between models, the s...
Optimal Shape for Forces and Moments on a Multi-Element Hydrofoil
2007-10-01
Hydrofoil DISTRIBUTION: Approved for public release; distribution is unlimited. This paper is part of the following report: TITLE: International...Michigan, 5-8 August 2007 Optimal Shape for Forces and Moments on a Multi-Element Hydrofoil Yu-Tai Lee1, Vineet Ahuja 2, Ashvin Hosangadi 2 and Michael...forces and The Tab Assisted Control (TAC) foil used for moments acting on the hydrofoil with adequate underwater control surfaces, shown in Fig. la, was
Geometric optimal design of MR damper considering damping force, control energy and time constant
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Q H; Choi, S B [Smart Structures and Systems Laboratory, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of); Kim, K S [Department of Mechanical and Automotive Engineering, Kongju National University, Chonan 330-240 (Korea, Republic of)], E-mail: seungbok@inha.ac.kr
2009-02-01
This paper presents an optimal design of magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies geometric dimensions of the damper that minimizes an objective function. The objective function is proposed by considering the damping force, dynamic range and the inductive time constant of the damper. After describing the configuration of the MR damper, a quasi-static modelling of the damper is performed based on Bingham model of MR fluid. The initial geometric dimensions of the damper are then determined based on the assumption of constant magnetic flux density throughout the magnetic circuit of the damper. Subsequently, the optimal design variables that minimize the objective function are determined using a golden-section algorithm and a local quadratic fitting technique via commercial finite element method parametric design language. A comparative work on damping force and time constant between the initial and optimal design is undertaken.
Optimization of the energy complex “NPP-accumulator” in case of force majeure
Zaluzhnaya, G.; Zagrebaev, A.
2017-01-01
We consider a problem of optimization of NPP with accumulator operation mode in case of force majeure. A mathematical formulation and solving of problem of energy output’s time behavior is provided. A mathematical formulation and solving of problem of energy’s optimum allocation to consumers with different priorities. Mathematically, the problem reduces to linear programming problem. We received that optimal time behavior is uniform energy output, and one should start with consumer with highest priority.
Optimal New Business for Insurer to Minimize the Ruin Probability under Interest Force
Institute of Scientific and Technical Information of China (English)
NIE Gao-qin; LIU Ci-hua; XU Li-xia
2007-01-01
Under constant interest force, the risk processes for old and new insurance business are modelled by Brownian motion with drift. By the stochastic control method, the explicit expressions for the minimum ruin probability and the corresponding optimal strategy are derived. Numerical example shows that the minimum probability of ruin and the optimal proportion for new business decrease as the interest rate increases, and vice versa.
Scheller, Johannes; Braza, Marianna; Triantafyllou, Michael
2016-11-01
Bats and other animals rapidly change their wingspan in order to control the aerodynamic forces. A NACA0013 type airfoil with dynamically changing span is proposed as a simple model to experimentally study these biomimetic morphing wings. Combining this large-scale morphing with inline motion allows to control both force magnitude and direction. Force measurements are conducted in order to analyze the impact of the 4 degree of freedom flapping motion on the flow. A blade-element theory augmented unsteady aerodynamic model is then used to derive optimal flapping trajectories.
Bandwidth Optimization in Centralized WLANs for Different Traffic Types
Directory of Open Access Journals (Sweden)
Haines RJ
2007-01-01
Full Text Available Allocating bandwidth between different forms of coexisting traffic (such as web-browsing, streaming, and telephony within a wireless LAN is a challenging and interesting problem. Centralized coordination functions in wireless LANs offer several advantages over distributed approaches, having the benefit of a system overview at the controller, but obtaining a stable configuration of bandwidth allocation for the system is nontrivial. We present, review, and compare different mechanisms to achieve this end, and a number of different means of obtaining the configurations themselves. We describe an analytical model of the system under consideration and present two mathematical approaches to derive solutions for any system configuration and deployment, along with an adaptive feedback-based solution. We also describe a comprehensive simulation-based model for the problem, and a prototype that allows comparison of these approaches. Our investigations demonstrate that a self-adaptive dynamic approach far outperforms any static scheme, and that using a mathematical model to produce the configurations themselves confers several advantages.
Novel algorithm for determining optimal blankholder forces in deep drawing of aluminum alloy sheet
Institute of Scientific and Technical Information of China (English)
孙成智; 陈关龙; 林忠钦; 赵亦希
2004-01-01
Wrinkling and fracture are main defects in sheet metal forming of aluminum alloy sheet, which can be reduced or even eliminated by manipulating a suitable blank-holder forces (BHF). But, it is difficult to attain the optimum BHF during sheet metal forming. A new optimization algorithm integrating the finite element method (FEM)and adaptive response surface method is presented to determinate the optimal BHFs in deep drawing of aluminum rectangular box. To assure convergence, the trust region modes management strategies are used to adjust the move limit of design spaces. Finally, the optimum results of rectangular box deep drawing are given. Verification experiments are performed to verify the optimal result.
Parameterization and optimization of the menthol force field for molecular dynamics simulations.
Jasik, Mateusz; Szefczyk, Borys
2016-10-01
Menthol's various biological properties render it a useful component for medical and cosmetological applications, while its three centers of asymmetry mean that it can be used in a range of organic reactions. Menthol-substituted ionic liquids (ILs) have been found to exhibit promising antimicrobial and antielectrostatic properties, as well as being useful in organic catalysis and biochemical studies. However, so far, a force field designed and validated specifically for the menthol molecule has not been constructed. In the present work, the validation and optimization of force field parameters with regard to the ability to reproduce the macroscopic properties of menthol is presented. The set of optimized potentials for liquid simulations all atom (OPLS-AA) compatible parameters was tested and carefully tuned. The refinement of parameters included fitting of partial atomic charges, optimization of Lennard-Jones parameters, and recalculation of the dihedral angle parameters needed to reproduce quantum energy profiles. To validate the force field, a variety of physicochemical properties were calculated for liquid menthol. Both thermodynamic and kinetic properties were taken into account, including density, surface tension, enthalpy of vaporization, and shear viscosity. The obtained force field was proven to accurately reproduce the properties of the investigated compound while being fully compatible with the OPLS-AA force field.
Cholewicki, J; McGill, S M
1994-10-01
There are two basic approaches to estimate individual muscle forces acting on a joint, given the indeterminacy of moment balance equations: optimization and electromyography (EMG) assisted. Each approach is characterized by unique advantages and liabilities. With this in mind, a new hybrid method which combines the advantages of both of these traditional approaches, termed 'EMG assisted optimization' (EMGAO), was described. In this method, minimal adjustments are applied to the individual muscle forces estimated from EMG, so that all moment equilibrium equations are satisfied in three dimensions. The result is the best possible match between physiologically observed muscle activation patterns and the predicted forces, while satisfying the moment constraints about all three joint axes. Several forms of the objective function are discussed and their effect on individual muscle adjustments is illustrated in a simple two-dimensional example.
Pyzer-Knapp, Edward O.; Thompson, Hugh P. G.; Day, Graeme M.
2016-01-01
We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%. PMID:27484370
Directory of Open Access Journals (Sweden)
Anita Jha
2016-06-01
Full Text Available These days one of the most important machining processes in industries is turning. Turning is affected by many factors such as the cutting velocity, feed rate, depth of cut and geometry of cutting tool etc., which are input parameters in this paper work. The desired product of dimensional accuracy and less surface roughness is influenced by cutting force and tool vibration which are the responses and the functions of these input parameters. In this paper work we determine the optimal setting of cutting parameters cutting speed, depth of cut, feed and of the tool by using artificial neural network to get a maximum cutting force an minimum surface roughness. This study highlights the use of modern optimization technique to optimize the multi response in turning operation.
An Optimal Angle of Launching a Point Mass in a Medium with Quadratic Drag Force
Chudinov, P
2005-01-01
A classic problem of the motion of a point mass (projectile) thrown at an angle to the horizon is reviewed. The air drag force is taken into account with the drag factor assumed to be constant. Analytic approach is used for investigation. The problem of finding an optimal angle of launching a point mass in a medium with quadratic drag force is considered. An equation for determining a value of this angle is obtained. After finding the optimal angle of launching, eight main parameters of the point mass motion are analytically determined. These parameters are used to construct analytically six main functional relationships of the problem. Simple analytic formulas are used to solve two problems of optimization aimed to maximize the flight range of a point mass and minimize the initial speed of the point mass for getting to the given point on the plane. The motion of a baseball is presented as an example.
Energy Technology Data Exchange (ETDEWEB)
Fukushima, Edwardo F.; Hirose, Shigeo [Tokyo Inst. of Tech. (Japan)
2000-05-01
This paper introduces an attitude control scheme based in optimal force distribution using quadratic programming which minimizes joint energy consumption. This method shares similarities with force distribution for multifingered hands, multiple coordinated manipulators and legged walking robots. In particular, an attitude control scheme was introduced inside the force distribution problem, and successfully implemented for control of the articulated body mobile robot KR-II. This is an actual mobile robot composed of cylindrical segments linked in series by prismatic joints and has a long snake-like appearance. These prismatic joints are force controlled so that each segment's vertical motion can automatically follow the terrain irregularities. An attitude control is necessary because this system acts like a system of wheeled inverted pendulum carts connected in series, being unstable by nature. The validity and effectiveness of the proposed method is verified by computer simulation and experiments with the robot KR-II. (author)
Institute of Scientific and Technical Information of China (English)
ZHOU Yunshan; LIU Jin'gang; CAI Yuanchun; ZOU Naiwei
2008-01-01
Associated dynamic performance of the clamping force control valve used in continuously variable transmission (CVT) is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dynamic model is set up by means of mechanism analysis. For the purpose of checking the validity of the modeling method, a prototype workpiece of the valve is manufactured for comparison test, and its simulation result follows the experimental result quite well. An associated performance index is founded considering the response time, overshoot and saving energy, and five structural parameters are selected to adjust for deriving the optimal associated performance index. The optimization problem is solved by the genetic algorithm (GA) with necessary constraints. Finally, the properties of the optimized valve are compared with those of the prototype workpiece, and the results prove that the dynamic performance indexes of the optimized valve are much better than those of the prototype workpiece.Key words: Dynamic modeling Optimal design Genetic algorithm Clamping force control valve Continuously variable transmission (CVT)
Reščič, J.; Kalyuzhnyi, Y. V.; Cummings, P. T.
2016-10-01
The approach developed earlier to describe the dimerizing shielded attractive shell (SAS) primitive model of chemical association due to Cummings and Stell is generalized and extended to include a description of a polymerizing SAS model. Our extension is based on the combination of the resummed thermodynamic perturbation theory for central force (RTPT-CF) associating potential and self consistent scheme, which takes into account the changes in the system free volume due to association. Theoretical results for thermodynamical properties of the model at different bonding length, density and temperature are compared against newly generated computer simulation results. The theory gives very accurate predictions for the model with bonding length L * from the range 0 < L * < 0.6 at all values of the density and temperature studied, including the limit of infinitely large temperature.
Bohra, Murtaza
Legged rovers are often considered as viable solutions for traversing unknown terrain. This work addresses the optimal locomotion reconfigurability of quadruped rovers, which consists of obtaining optimal locomotion modes, and transitioning between them. A 2D sagittal plane rover model is considered based on a domestic cat. Using a Genetic Algorithm, the gait, pose and control variables that minimize torque or maximize speed are found separately. The optimization approach takes into account the elimination of leg impact, while considering the entire variable spectrum. The optimal solutions are consistent with other works on gait optimization, and are similar to gaits found in quadruped animals as well. An online model-free gait planning framework is also implemented, that is based on Central Pattern Generators is implemented. It is used to generate joint and control trajectories for any arbitrarily varying speed profile, and shown to regulate locomotion transition and speed modulation, both endogenously and continuously.
Cianchetti, Flor A; Valero-Cuevas, Francisco J
2010-01-01
Moving our fingertips toward objects to produce well-directed forces immediately upon contact is fundamental to dexterous manipulation. This apparently simple motion-to-force transition in fact involves a time-critical, predictive switch in control strategy. Given that dexterous manipulation must accommodate multiple mechanical conditions, we investigated whether and how this transition adapts to task difficulty. Eight adults (19-39 yr) produced ramps of isometric vertical fingertip force against a rigid surface immediately following a tapping motion. By changing target surface friction and size, we defined an easier (sandpaper, 11 mm diam) versus a more difficult (polished steel, 5 mm diam) task. As in prior work, we assembled fine-wire electromyograms from all seven muscles of the index finger into a seven-dimensional vector defining the full muscle coordination pattern-and quantified its temporal evolution as its alignment with a reference coordination pattern vector for steady-state force production. As predicted by numerical optimizations to neuromuscular delays, our empirical and sigmoidal nonlinear regression analyses show that the coordination pattern transitions begin sooner for the more difficult tasks than for the easier tasks ( approximately 120 ms, P 0.7 in most cases). Importantly, the force vector following contact had smaller directional error (P optimization to counteract neuromuscular delays and noise to enable this fundamental element of dexterous manipulation.
Reliability assessment to determine the optimal forced outage rate of components
Directory of Open Access Journals (Sweden)
Habib Daryabad
2014-03-01
Full Text Available Determining the optimal forced outage rate (FOR ofcomponents can lead to reducing the operational and maintenance costs inelectric power systems. FOR is closely associated with two factors: number ofoutages and duration of outages. Therefore, it is possible to decrease the FORthrough decreasing the number of outages or reducing the duration ofoutages. Decreasing number of outages is usually carried out throughreinforcement of the network and reducing the duration of outages is mainlyperformed through increasing the repair and maintenance groups. Both of theproposed methods to decrease the FOR possess the costs. Therefore, it is verysuitable to find the optimal rate of FOR and avoiding unnecessary costs. Thispaper presents a new methodology to find the optimal rate of FOR. In thisregard, the system reliability is assessed and evaluated from view of FOR andthe optimal rate of FOR is denoted for all components.
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The design method of a 6-axis force robot's transducer based on the Stewart platform is detailed.For this purpose, the sensitivity isotropy evaluation criteria of the transducer are defined, and by the aid of computer, the relationships between the criteria and the parameters of all the transducers based on the Stewart platform are investigated within the geometric model of the solution space, which can provide the theoretical background for the optimal construction design of the 6-axis force transducer related to the sensitivity isotropy.
Raiszadeh, Behzad; Queen, Eric M.; Hotchko, Nathaniel J.
2009-01-01
A capability to simulate trajectories of multiple interacting rigid bodies has been developed, tested and validated. This capability uses the Program to Optimize Simulated Trajectories II (POST 2). The standard version of POST 2 allows trajectory simulation of multiple bodies without force interaction. In the current implementation, the force interaction between the parachute and the suspended bodies has been modeled using flexible lines, allowing accurate trajectory simulation of the individual bodies in flight. The POST 2 multibody capability is intended to be general purpose and applicable to any parachute entry trajectory simulation. This research paper explains the motivation for multibody parachute simulation, discusses implementation methods, and presents validation of this capability.
Performance optimization of force feedback control system in virtual vascular intervention surgery.
Hu, Zhi; Cai, Ping; Qin, Peng; Xie, Le
2014-01-01
In virtual surgery of minimally invasive vascular intervention, the force feedback is transmitted through the flexible guide wire. The disturbance caused by the flexible deformation would affect the fidelity of the VR (virtual reality) training. SMC (sliding mode control) strategy with delayed-output observer is adopted to suppress the effect of flexible deformation. In this study, the control performance of the strategy is assessed when the length of guide wire between actuator and the operating point changes. The performance assessment results demonstrate the effectiveness of the proposed method and find the optimal length of guide wire for the force feedback control.
Optimization Mathematical Model of Pile Forces for Offshore Piled Breasting Dolphins
Institute of Scientific and Technical Information of China (English)
周锡礽; 王东芹; 王晖; 朱福明
2004-01-01
An optimization mathematical model of the pile forces for piled breasting dolphins in the open sea under various loading conditions is presented. The optimum layout with the well distributed pile forces and the least number of piles is achieved by the multiplier penalty function method. Several engineering cases have been calculated and compared with the result of the conventional design method. It is shown that the number of piles can be reduced at least by 10% ～ 20%and the piles' bearing state is improved greatly.
Yang, Jian; Cong, Weijian; Chen, Yang; Fan, Jingfan; Liu, Yue; Wang, Yongtian
2014-02-21
The clinical value of the 3D reconstruction of a coronary artery is important for the diagnosis and intervention of cardiovascular diseases. This work proposes a method based on a deformable model for reconstructing coronary arteries from two monoplane angiographic images acquired from different angles. First, an external force back-projective composition model is developed to determine the external force, for which the force distributions in different views are back-projected to the 3D space and composited in the same coordinate system based on the perspective projection principle of x-ray imaging. The elasticity and bending forces are composited as an internal force to maintain the smoothness of the deformable curve. Second, the deformable curve evolves rapidly toward the true vascular centerlines in 3D space and angiographic images under the combination of internal and external forces. Third, densely matched correspondence among vessel centerlines is constructed using a curve alignment method. The bundle adjustment method is then utilized for the global optimization of the projection parameters and the 3D structures. The proposed method is validated on phantom data and routine angiographic images with consideration for space and re-projection image errors. Experimental results demonstrate the effectiveness and robustness of the proposed method for the reconstruction of coronary arteries from two monoplane angiographic images. The proposed method can achieve a mean space error of 0.564 mm and a mean re-projection error of 0.349 mm.
Edwards, Devin T; Faulk, Jaevyn K; Sanders, Aric W; Bull, Matthew S; Walder, Robert; LeBlanc, Marc-Andre; Sousa, Marcelo C; Perkins, Thomas T
2015-10-14
Atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) is widely used to mechanically measure the folding and unfolding of proteins. However, the temporal resolution of a standard commercial cantilever is 50-1000 μs, masking rapid transitions and short-lived intermediates. Recently, SMFS with 0.7-μs temporal resolution was achieved using an ultrashort (L = 9 μm) cantilever on a custom-built, high-speed AFM. By micromachining such cantilevers with a focused ion beam, we optimized them for SMFS rather than tapping-mode imaging. To enhance usability and throughput, we detected the modified cantilevers on a commercial AFM retrofitted with a detection laser system featuring a 3-μm circular spot size. Moreover, individual cantilevers were reused over multiple days. The improved capabilities of the modified cantilevers for SMFS were showcased by unfolding a polyprotein, a popular biophysical assay. Specifically, these cantilevers maintained a 1-μs response time while eliminating cantilever ringing (Q ≅ 0.5). We therefore expect such cantilevers, along with the instrumentational improvements to detect them on a commercial AFM, to accelerate high-precision AFM-based SMFS studies.
Men'shikov, V V
2014-04-01
The optimization of money expenditure for healthcare is leading to the reorganization of the structure of medical organizations, to reducing of small establishments, to centralization of laboratory analyses with cessation of their performing in some hospitals and out patient offices. This tendency is based on medical (enlargement of laboratory tests spectrum) and economical (high productivity, relative reducing of net cost of laboratory determinations) reasons. But the repercussions of switch-over to centralization of laboratory analyses performance must be evaluated from the position of laboratory information accessibility tacking in account the need in express analyses for patient, situated on territories outlying from the centralized laboratory. Using of the portative analytical devices and therefore the possibility to perform the urgent analyses by non-laboratory personal in point of care and by patients themselves as a matter of self-testing can help to solve the problem of accessibility of laboratory tests in conditions of laboratory centralization in some regions.
Institute of Scientific and Technical Information of China (English)
LIU Zi-ping; LI Li-xin
2013-01-01
Based on the niche genetic algorithm, the intelligent and optimizing model for the rolling force distribution in hot strip mills was put forward. The research showed that the model had many advantages such as fast searching speed, high calculating pre-cision and suiting for on-line calculation. A good strip shape could be achieved by using the model and it is appropriate and practica-ble for rolling producing.
Dynamics and Optimal Feet Force Distributions of a Realistic Four-legged Robot
Directory of Open Access Journals (Sweden)
Saurav Agarwal
2012-08-01
Full Text Available This paper presents a detailed dynamic modeling of realistic four-legged robot. The direct and inverse kinematic analysis for each leg has been considered in order to develop an overall kinematic model of the robot, when it follows a straight path. This study also aims to estimate optimal feet force distributions of the said robot, which is necessary for its real-time control. Three different approaches namely, minimization of norm of feet forces (approach 1, minimization of norm of joint torques (approach 2 and minimization of norm of joint power (approach 3 have been developed. Simulation result shows that approach 3 is more energy efficient foot force formulation than other two approaches. Lagrange-Euler formulation has been utilized to determine the joint torques. The developed dynamic models have been examined through computer simulation of continuous gait of the four-legged robot.
Optimized Reduction of Unsteady Radial Forces in a Singlechannel Pump for Wastewater Treatment
Kim, Jin-Hyuk; Cho, Bo-Min; Choi, Young-Seok; Lee, Kyoung-Yong; Peck, Jong-Hyeon; Kim, Seon-Chang
2016-11-01
A single-channel pump for wastewater treatment was optimized to reduce unsteady radial force sources caused by impeller-volute interactions. The steady and unsteady Reynolds- averaged Navier-Stokes equations using the shear-stress transport turbulence model were discretized by finite volume approximations and solved on tetrahedral grids to analyze the flow in the single-channel pump. The sweep area of radial force during one revolution and the distance of the sweep-area center of mass from the origin were selected as the objective functions; the two design variables were related to the internal flow cross-sectional area of the volute. These objective functions were integrated into one objective function by applying the weighting factor for optimization. Latin hypercube sampling was employed to generate twelve design points within the design space. A response-surface approximation model was constructed as a surrogate model for the objectives, based on the objective function values at the generated design points. The optimized results showed considerable reduction in the unsteady radial force sources in the optimum design, relative to those of the reference design.
A fair method for centralized optimization of multi-TSO power systems
Energy Technology Data Exchange (ETDEWEB)
Phulpin, Yannick; Petit, Marc [SUPELEC, Department of Power and Energy Systems, 3 rue Joliot Curie, 91192 Gif sur Yvette (France); Begovic, Miroslav [Georgia Institute of Technology, Atlanta, GA (United States); Ernst, Damien [University of Liege, Liege (Belgium)
2009-10-15
This paper addresses the problem of centralized optimization of an interconnected power system partitioned into several regions controlled by different transmission system operators (TSOs). It is assumed that those utilities have agreed to transferring some of their competencies to a centralized control center, which is in charge of setting the control variables in the entire system to satisfy every utility's individual objective. This paper proposes an objective method for centralized optimization of such multi-TSO power systems, which relies on the assumption that each TSO has a real-valued optimization function focusing on its control area only. This method is illustrated on the IEEE 118 bus system partitioned into three TSOs. It is applied to the optimal reactive power dispatch problem, where the control variables are the voltage settings for generators and compensators. After showing that the method has some properties of fairness, namely freedom from envy, efficiency, accountability, and altruism, we emphasize its robustness with respect to certain biased behavior of the different TSOs. (author)
Directory of Open Access Journals (Sweden)
Suleyman Neseli
2014-10-01
Full Text Available This research outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in drilling of AISI 1040 steel. The drilling parameters evaluated are cutting speed, feed rate, and helix angle. Series of experiments are conducted to relate the cutting parameters on the thrust force and torque. L27(313 orthogonal array, signal-to-noise ratio is employed to analyze the influence of these parameters on thrust force and torque during drilling. Analysis of variance (ANOVA is used to study the effect of process parameters on machining process. The study shows that the Taguchi method is suitable to solve the stated problem with the minimum number of trials. The main objective is to find the important factors and combination of factors that influence the machining process to achieve low thrust force and torque. The analysis of the Taguchi method indicates that the feed rate is the most significant factor affecting the thrust force, while the cutting speed contributes the most to the torque.
Biscarini, Andrea
2012-01-01
A model has been developed to definitively characterize the resistance properties and the joint loading (i.e., shear and compressive components of the joint reaction force) in single-joint exercises with ideal elastic bands. The model accounts for the relevant geometric and elastic properties of the band, the band pre-stretching, and the relative positioning among the joint center of rotation and the fixation points of the band. All the possible elastic torque profiles of ascending-descending, descending, or ascending type were disclosed in relation to the different ranges of joint angles. From these results the elastic resistance setting that best reproduces the average-user's knee extensor torque in maximal isometric/isokinetic efforts was determined. In this optimized setting, the shear tibiofemoral reaction force corresponding to an anterior (posterior) tibial displacement was 65% smaller than (nearly the same as) that obtained in a cam-equipped leg-extension equipment for equal values of resistance torque peak, whereas the compressive tibiofemoral reaction force was 22% higher. Compared to a weight-stack leg-extension equipment, an elastic resistance optimized setting has the potential to give a more effective quadriceps activation across the range of motion, and greatly reduces the anterior cruciate ligament strain force, which represents the main drawback of existing open kinetic-chain knee-extension exercises.
Graybill, George
2007-01-01
Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.
Structural Optimization of a Force Balance Using a Computational Experiment Design
Parker, P. A.; DeLoach, R.
2002-01-01
This paper proposes a new approach to force balance structural optimization featuring a computational experiment design. Currently, this multi-dimensional design process requires the designer to perform a simplification by executing parameter studies on a small subset of design variables. This one-factor-at-a-time approach varies a single variable while holding all others at a constant level. Consequently, subtle interactions among the design variables, which can be exploited to achieve the design objectives, are undetected. The proposed method combines Modern Design of Experiments techniques to direct the exploration of the multi-dimensional design space, and a finite element analysis code to generate the experimental data. To efficiently search for an optimum combination of design variables and minimize the computational resources, a sequential design strategy was employed. Experimental results from the optimization of a non-traditional force balance measurement section are presented. An approach to overcome the unique problems associated with the simultaneous optimization of multiple response criteria is described. A quantitative single-point design procedure that reflects the designer's subjective impression of the relative importance of various design objectives, and a graphical multi-response optimization procedure that provides further insights into available tradeoffs among competing design objectives are illustrated. The proposed method enhances the intuition and experience of the designer by providing new perspectives on the relationships between the design variables and the competing design objectives providing a systematic foundation for advancements in structural design.
Optimization of Blank Holding Force in Deep Drawing Process Using Friction Property of Steel Blank
Directory of Open Access Journals (Sweden)
Prasad S. Pandhare
2012-08-01
Full Text Available Majority of automobile and appliances component are made by deep drawing sheet metal process. So these growing need demands a new design methodology based on metal forming simulation. With the help of metal forming simulation we can identify the problem areas and solutions can be validated in computers without any expensive shop floor operations prior to any tool construction. Metal forming simulation is also helpful at the product and tool design stage to decide various parameters. Problem and improvements in each area of the SDF technology and their interactions should be considered. In the product and process design phases in order to optimize Blank Holding Force which is one of the important parameters in Deep Drawing process. Sometimes accuracies of frictional values have more effect on the simulation results than most of the material properties. So that friction plays a major role during optimization of Blank Holding Force. In this paper, the friction is varied in six different values. CRDQ Steel is used as a material. For each value of friction and its corresponding B.H.F., Forming Limit Diagrams are drawn by using hyper mesh module of Hyper Form Solver software. Also the effect of these two parameters on occurrence of wrinkling during the process is studied. Thus, optimized range of coefficient of friction in which product is safe as well as having minimized wrinkles along with optimized B.H.F. is calculated.
Eksioglu, Mahmut
2006-02-10
The aim of this study was to investigate the maximum acceptable contraction frequencies (i.e. work-rest cycles) for an isometric-intermittent handgrip task as a function of grip span, applied force and shoulder posture using psychophysical and physiological approaches. Twelve healthy males served as subjects. The three grip spans investigated were the optimal, 2 cm narrower than the optimal, and 2 cm wider than the optimal. The grip force levels studied were 15% and 30% of maximum voluntary grip force and the two shoulder postures were 25 degrees flexion and 30 degrees abduction. The psychophysical results indicate that subjects work faster with the narrower grip span at 15% of maximum voluntary grip force level in comparison to working with the optimal and the wider spans. However, when the task required 30% of maximum grip force level, the subjects worked faster with the optimal grip span. These findings were supported by the results of electromyography, heart rate, blood pressure and perceived discomfort. The study suggests that grip span of a tool is an important factor to be considered in predicting optimal work-rest cycles for hand grip tasks, and the optimum setting of grip span of the hand-tool depends on the required task force level. That is, the optimality is relative rather than absolute. In addition, it appears that weaker subjects can work at a higher rate than stronger ones at the same relative force level.
Au + Au central collisions at 150, 250 and 400 A MeV energies in QMD with relativistic forces
Németh, J; Feldmeier, H
1999-01-01
Using the small acceleration approximation we derive a relativistic scalar-vector force from a modified Zimanyi-Moszkowski Lagrangian based on sigma, omega and rho meson exchanges. The momentum dependence of the force is fixed automatically by the theory. We present an application of such a force in a QMD calculation at intermediate energies comparing the results with the experimental ones published recently by the FOPI collaboration. For most of the quantities (number of intermediate mass fragments, ERAT, integrated side flow, central flow, charge distributions, etc.) we find agreement with the experimental results.
Paramfit: automated optimization of force field parameters for molecular dynamics simulations.
Betz, Robin M; Walker, Ross C
2015-01-15
The generation of bond, angle, and torsion parameters for classical molecular dynamics force fields typically requires fitting parameters such that classical properties such as energies and gradients match precalculated quantum data for structures that scan the value of interest. We present a program, Paramfit, distributed as part of the AmberTools software package that automates and extends this fitting process, allowing for simplified parameter generation for applications ranging from single molecules to entire force fields. Paramfit implements a novel combination of a genetic and simplex algorithm to find the optimal set of parameters that replicate either quantum energy or force data. The program allows for the derivation of multiple parameters simultaneously using significantly fewer quantum calculations than previous methods, and can also fit parameters across multiple molecules with applications to force field development. Paramfit has been applied successfully to systems with a sparse number of structures, and has already proven crucial in the development of the Assisted Model Building with Energy Refinement Lipid14 force field.
Dust, Elemental Carbon and Other Impurities on Central Asian Glaciers: Origin and Radiative Forcing
Schmale, J.; Flanner, M.; Kang, S.; Sprenger, M.; Zhang, Q.; Li, Y.; Guo, J.; Schwikowski, M.
2015-12-01
In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and radiative forcing (RF). 218 snow samples were taken from 13 snow pits on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental and organic carbon by a thermo-optical method, mineral dust by gravimetry, and iron by ICP-MS. Back trajectory ensembles were released every 6 hours with the Lagranto model for the covered period at all sites. Boundary layer "footprints" were calculated to estimate general source regions and combined with MODIS fire counts for potential fire contributions. Albedo reduction due to black carbon and mineral dust was calculated with the Snow-Ice-Aerosol-Radiative model (SNICAR), and surface spectral irradiances were derived from atmospheric radiative transfer calculations to determine the RF under clear-sky and all sky conditions using local radiation measurements. Dust contributions came from Central Asia, the Arabian Peninsula, the Sahara and partly the Taklimakan. Fire contributions were higher in 2014 and generally came from the West and North. We find that EC exerts roughly 3 times more RF than mineral dust in fresh and relatively fresh snow (~5 W/m2) and up to 6 times more in snow that experienced melting (> 10 W/m2) even though EC concentrations (average per snow pit from 90 to 700 ng/g) were up to two orders of magnitude lower than mineral dust (10 to 140 μg/g).
Sakae, Yoshitake
2013-01-01
We propose a novel method for refining force-field parameters of protein systems. In this method, the agreement of the secondary-structure stability and instability between the protein conformations obtained by experiments and those obtained by molecular dynamics simulations is used as a criterion for the optimization of force-field parameters. As an example of the applications of the present method, we refined the force-field parameter set of the AMBER ff99SB force field by searching the torsion-energy parameter spaces of $\\psi$ (N-C$^{\\alpha}$-C-N) and $\\zeta$ (C$^{\\beta}$-C$^{\\alpha}$-C-N) of the backbone dihedral angles. We then performed folding simulations of $\\alpha$-helical and $\\beta$-hairpin peptides, using the optimized force field. The results showed that the new force-field parameters gave structures more consistent with the experimental implications than the original AMBER ff99SB force field.
Energy Technology Data Exchange (ETDEWEB)
Krstulovich, S.F.
1986-11-12
This report is developed as part of the Fermilab Central Computing Facility Project Title II Design Documentation Update under the provisions of DOE Document 6430.1, Chapter XIII-21, Section 14, paragraph a. As such, it concentrates primarily on HVAC mechanical systems design optimization and cost analysis and should be considered as a supplement to the Title I Design Report date March 1986 wherein energy related issues are discussed pertaining to building envelope and orientation as well as electrical systems design.
Institute of Scientific and Technical Information of China (English)
Xin; LI; Haijing; HU
2013-01-01
According to the theories of institutional economics and development economics,the positive and negative externality of rural labor force flowing from central and western regions and into eastern regions of China were analyzed,and then it was proposed that it is necessary to positive externality,rather than take"household register"measures to solve the problem simply.
Albedo changes, Milankovitch forcing, and late quaternary climate changes in the central Andes
Energy Technology Data Exchange (ETDEWEB)
Kull, C.; Grosjean, M. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Dept. of Geography
1998-11-01
Late quaternary humidity changes resulted in substantial modifications of the land surface characteristics in the Altiplano of the Atacama desert, central Andes. Reconstructions of surface albedo, top-of-atmosphere (TOA) albedo, and shortwave net radiation in the Andes of northern Chile for 20,14,10,7 and 0 ka suggest that surface and TOA albedo increased substantially during periods of relatively humid environmental conditions (i.e., with large palaeolakes, glaciers and dense vegetation). The decrease of summer shortwave net radiation and seasonality during the late-glacial/early Holocene humid phase (14 to 10 ka) due to Earth`s surface and atmospheric characteristics added to the effect of orbitally driven negative deviations of southern Hemisphere austral summer insolation and minimum seasonality at 20 S. Therefore, in situ radiative forcing is, in contrast to the Northern Hemisphere tropics, not a suitable explanation for enhanced convective precipitation and, ultimately, humid climatic conditions. Our results suggest that late Quaternary humidity changes on the Altiplano reflect a collective response to (1) environmental changes in the source area of the moisture (e.g., reexpansion of the rain forest and increased release of latent heat over Amazonia and the Chaco, warm sea surface temperatures in the E Pacific) and, (2) large-scale circulation patterns and wave structures in the upper troposphere (strength and position of the Bolivian high, divergent flow stimulating convection over the Altiplano), or that they even reflect a response to (3) interhemispherical teleconnections. (orig.) With 5 figs., 2 tabs., 45 refs.
Elfgen, Roman; Hülsmann, Marco; Krämer, Andreas; Köddermann, Thorsten; Kirschner, Karl N.; Reith, Dirk
2016-10-01
Molecular simulations are an important tool in the study of aqueous salt solutions. To predict the physical properties accurately and reliably, the molecular models must be tailored to reproduce experimental data. In this work, a combination of recent global and local optimization tools is used to derive force fields for MgCl2 (aq) and CaCl2 (aq). The molecular models for the ions are based on a Lennard-Jones (LJ) potential with a superimposed point charge. The LJ parameters are adjusted to reproduce the bulk density and shear viscosity of the different solutions at 1 bar and temperatures of 293.15, 303.15, and 318.15 K. It is shown that the σ-value of chloride consistently has the strongest influence on the system properties. The optimized force field for MgCl2 (aq) provides both properties in good agreement with the experimental data over a wide range of salt concentrations. For CaCl2 (aq), a compromise was made between the bulk density and shear viscosity, since reproducing the two properties requires two different choices of the LJ parameters. This is demonstrated by studying metamodels of the simulated data, which are generated to visualize the correlation between the parameters and observables by using projection plots. Consequently, in order to derive a transferable force field, an error of ˜3% on the bulk density has to be tolerated to yield the shear viscosity in satisfactory agreement with experimental data.
Kawaura, Kazuaki; Miki, Risa; Shima, Eriko; Honda, Sokichi; Soeda, Fumio; Shirasaki, Tetsuya; Takahama, Kazuo
2010-09-13
Recently, we reported that a centrally acting non-narcotic antitussive (cough suppressant drug), tipepidine produces an antidepressant-like effect in the forced swimming test in rats. Because pharmacological properties of tipepidine apparently differ from those of typical antidepressants developed to date, we speculated that caramiphen, another centrally acting antitussive, has an antidepressant-like effect. That effect of caramiphen was studied in rats using the forced swimming test. Caramiphen at 20 and 40mg/kg i.p. significantly reduced immobility. At 40mg/kg i.p., it increased climbing behavior. Even at 40mg/kg, this drug had no effect on locomotor activity. Results suggest that a centrally acting antitussive possessing inhibition of GIRK channels has an antidepressant-like effect.
Ravera, Emiliano Pablo; Crespo, Marcos José; Braidot, Ariel Andrés Antonio
2016-01-01
Clinical gait analysis provides great contributions to the understanding of gait patterns. However, a complete distribution of muscle forces throughout the gait cycle is a current challenge for many researchers. Two techniques are often used to estimate muscle forces: inverse dynamics with static optimization and computer muscle control that uses forward dynamics to minimize tracking. The first method often involves limitations due to changing muscle dynamics and possible signal artefacts that depend on day-to-day variation in the position of electromyographic (EMG) electrodes. Nevertheless, in clinical gait analysis, the method of inverse dynamics is a fundamental and commonly used computational procedure to calculate the force and torque reactions at various body joints. Our aim was to develop a generic musculoskeletal model that could be able to be applied in the clinical setting. The musculoskeletal model of the lower limb presents a simulation for the EMG data to address the common limitations of these techniques. This model presents a new point of view from the inverse dynamics used on clinical gait analysis, including the EMG information, and shows a similar performance to another model available in the OpenSim software. The main problem of these methods to achieve a correct muscle coordination is the lack of complete EMG data for all muscles modelled. We present a technique that simulates the EMG activity and presents a good correlation with the muscle forces throughout the gait cycle. Also, this method showed great similarities whit the real EMG data recorded from the subjects doing the same movement.
Determination of Optimal Energy Efficient Separation Schemes based on Driving Forces
DEFF Research Database (Denmark)
Bek-Pedersen, Erik; Gani, Rafiqul; Levaux, O.
2000-01-01
A new integrated approach for synthesis, design and operation of separation schemes is presented. This integrated approach is based on driving forces that promote the desired separation for different separation techniques. A set of algorithms needed by the integrated approach for sequencing...... and design of distillation columns and for generating hybrid separation schemes are presented. The main feature of these algorithms is that they provide a 'visual' solution that also appears to be near optimal in terms of energy consumption. Several illustrative examples highlighting the application...
Energy Technology Data Exchange (ETDEWEB)
Cai, Jiandong; Zhang, Li [Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin, NT (Hong Kong); Wang, Michael Yu, E-mail: michael.wang@nus.edu.sg [Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin, NT (Hong Kong); Department of Mechanical Engineering, National University of Singapore, Singapore 117575 (Singapore)
2015-12-15
In multifrequency atomic force microscopy (AFM), probe’s characteristic of assigning resonance frequencies to integer harmonics results in a remarkable improvement of detection sensitivity at specific harmonic components. The selection criterion of harmonic order is based on its amplitude’s sensitivity on material properties, e.g., elasticity. Previous studies on designing harmonic probe are unable to provide a large design capability along with maintaining the structural integrity. Herein, we propose a harmonic probe with step cross section, in which it has variable width in top and bottom steps, while the middle step in cross section is kept constant. Higher order resonance frequencies are tailored to be integer times of fundamental resonance frequency. The probe design is implemented within a structural optimization framework. The optimally designed probe is micromachined using focused ion beam milling technique, and then measured with an AFM. The measurement results agree well with our resonance frequency assignment requirement.
Optimal decay rate of vibrating beam equations controlled by combined boundary feedback forces
Institute of Scientific and Technical Information of China (English)
于景元; 李胜家; 王耀庭; 粱展东
1999-01-01
The optimal decay rate problem is considered for boundary control system modeling by a flexible structure consisting of a Eular-Bernoulli beam. Controls are a bending moment in proportion to angular velocity and a shear force in proportion to velocity. A sensitivity asymptotic analysis of the system’ s eigenvalues and eigenfunctions is set up. It is proved that, for every 0
Energy Technology Data Exchange (ETDEWEB)
Hirose, Takahumi; Akata, Soichi; Matsuno, Naoto; Nagao, Takeshi; Abe, Kimihiko [Tokyo Medical Coll. (Japan)
2002-01-01
Three-dimensional (3D) image reconstruction of central airways using helical CT requires several user-defined parameters that exceed the requirements of conventional CT. The purpose of this study was to evaluate the optimal parameters for 3D images of central airways using helical CT. In our experimental study using a piglet immediately after sacrifice, 3D images of the central airway were evaluated with changes of 3D imaging parameters, such as detector collimation (1, 2, 3 and 6 mm), table speed (1, 2, 3 and 5 mm/sec), tube electric current (50, 100, 150, 200 and 250 mA), reconstruction interval (0.3, 0.5, 1, 2 and 3 mm), algorithm (mediastinum and lung) and interpolation method (180 deg and 360 deg). To minimize detector collimation, table speed, and reconstruction interval could provide the best 3D images of the central airway. Stair-step artifacts could also be reduced with a slow table speed. However, decreasing the collimation and table speed decreases not only the effective section thickness but also the scan coverage that can be achieved with a helical CT. For routine diagnosis, we conclude that optimal parameters for 3D images of the central airway are to minimize the table speed necessary to cover the volume of interest and to set detector collimation to 1/2 of the table speed. The reconstruction intervals should also be selected at up to 1/2 of the detector collimation, but with trade-offs of increased image processing time, data storage requirements, and physician time for image review. Regarding to tube electric current, 200 mA or more was necessary. Pixel noise increased with the algorithm for the lung. The 180 deg interpolation is better than 360 deg interpolation due to thin effective section thickness. (author)
Simultaneous optimization of force and placement of friction dampers under seismic loading
Fleck Fadel Miguel, Letícia; Fleck Fadel Miguel, Leandro; Holdorf Lopez, Rafael
2016-04-01
It is known that the use of passive energy-dissipation devices, such as friction dampers, reduces considerably the dynamic response of a structure subjected to earthquake ground motions. Nevertheless, the parameters of each damper and the best placement of these devices remain difficult to determine. Some articles on optimum design of tuned mass dampers and viscous dampers have been published; however, there is a lack of studies on optimization of friction dampers. The main contribution of this article is to propose a methodology to simultaneously optimize the location of friction dampers and their friction forces in structures subjected to seismic loading, to achieve a desired level of reduction in the response. For this purpose, the recently developed backtracking search optimization algorithm (BSA) is employed, which can deal with optimization problems involving mixed discrete and continuous variables. For illustration purposes, two different structures are presented. The first is a six-storey shear building and the second is a transmission line tower. In both cases, the forces and positions of friction dampers are the design variables, while the objective functions are to minimize the interstorey drift for the first case and to minimize the maximum displacement at the top of the tower for the second example. The results show that the proposed method was able to reduce the interstorey drift of the shear building by more than 65% and the maximum displacement at the top of the tower by approximately 55%, with only three friction dampers. The proposed methodology is quite general and it could be recommended as an effective tool for optimum design of friction dampers for structural response control. Thus, this article shows that friction dampers can be designed in a safe and economic way.
Modgil, Girish A.
Gas turbine engines for aerospace applications have evolved dramatically over the last 50 years through the constant pursuit for better specific fuel consumption, higher thrust-to-weight ratio, lower noise and emissions all while maintaining reliability and affordability. An important step in enabling these improvements is a forced response aeromechanics analysis involving structural dynamics and aerodynamics of the turbine. It is well documented that forced response vibration is a very critical problem in aircraft engine design, causing High Cycle Fatigue (HCF). Pushing the envelope on engine design has led to increased forced response problems and subsequently an increased risk of HCF failure. Forced response analysis is used to assess design feasibility of turbine blades for HCF using a material limit boundary set by the Goodman Diagram envelope that combines the effects of steady and vibratory stresses. Forced response analysis is computationally expensive, time consuming and requires multi-domain experts to finalize a result. As a consequence, high-fidelity aeromechanics analysis is performed deterministically and is usually done at the end of the blade design process when it is very costly to make significant changes to geometry or aerodynamic design. To address uncertainties in the system (engine operating point, temperature distribution, mistuning, etc.) and variability in material properties, designers apply conservative safety factors in the traditional deterministic approach, which leads to bulky designs. Moreover, using a deterministic approach does not provide a calculated risk of HCF failure. This thesis describes a process that begins with the optimal aerodynamic design of a turbomachinery blade developed using surrogate models of high-fidelity analyses. The resulting optimal blade undergoes probabilistic evaluation to generate aeromechanics results that provide a calculated likelihood of failure from HCF. An existing Rolls-Royce High Work Single
Directory of Open Access Journals (Sweden)
Liaquat Ali Khan
2012-01-01
Full Text Available Energy efficient systems are the most desirable systems. Due to huge rise in energy prices and lack of availability of energy, the effective use of energy has become the need of time. Energy recovery both in heating systems as well as in air-conditioning systems saves a lot of energy. In this paper energy recovery system has been designed and optimized for central air-conditioning systems for various ranges. Cost function includes capital cost along with pumping and exergy destruction cost. This shows that installation of energy recovery system with a central air-conditioning has a significant amount of saved energy and payback period is within a year. PFHE (Plate Fin Heat Exchanger is designed and optimized using evolutionary optimization. In order to verify the capabilities of the proposed method, a case study is also presented showing that significant amount of energy is recovered at a reasonable payback period. Sensitivity analysis is also done with the energy prices.
Arabi, Alya A.
2016-11-01
Modelling dispersion interactions with traditional density functional theory (DFT) is a challenge that has been extensively addressed in the past decade. The exchange-dipole moment (XDM), among others, is a non-empirical add-on dispersion correction model in DFT. The functional PW86+PBE+XDM for exchange, correlation and dispersion, respectively, compromises an accurate functional for thermochemistry and for van der Waals (vdW) complexes at equilibrium and non-equilibrium geometries. To use this functional in optimizing vdW complexes, rather than computing single point energies, it is necessary to evaluate accurate forces. The purpose of this paper is to validate that, along the potential energy surface, the distance at which the energy is minimum is commensurate with the distance at which the forces vanish to zero. This test was validated for 10 rare gas diatomic molecules using various integration grids and different convergence criteria. It was found that the use of either convergence criterion, 10-6 or 10-8, in Gaussian09, does not affect the accuracy of computed optimal distances and binding energies. An ultra-fine grid needs to be used when computing accurate energies using generalized gradient approximation functionals. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
Institute of Scientific and Technical Information of China (English)
KONG Haining; QI Ershi; LI Gang; HE Shuguang; ZHANG Xian
2009-01-01
The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield. A total of 20 experiments at random were conducted to in-vestigate the effect of reaction temperature, Si/Al ratios of H-ZSM-5 catalyst and liquid hourly space velocity (LHSV)on the ethylene yield. The results show that the relationship between ethylene yield and the three signifi-cant independent variables can be approximated by a nonlinear polynomial model, with R-squared of 99.9% and adjusted R-squared of 99.8%. The maximal response for ethylene yield is 93.4% under the optimal condition of 328 ℃, Si/Al ratio 85, and LHSV 3.8 h-1.
Supply Chain Network Optimization Based on Fuzzy Multiobjective Centralized Decision-Making Model
Directory of Open Access Journals (Sweden)
Xinyi Fu
2017-01-01
Full Text Available Supply chain cooperation strategy believes that the integration of the operation process can produce value for customers, optimize the supply chain of the connection between the vertical nodes, and constantly strengthen the performance of the advantages, so as to achieve mutual benefit and win-win results. Under fuzzy uncertain environment and centralized decision-making mode, we study multiobjective decision-making optimization, which focuses on equilibrium and compensation of multiobjective problems; that is to say, the proper adjustment of the individual goal satisfaction level will make other goals’ satisfaction levels change greatly. Through coordination among the multiobjectives, supply chain system will achieve global optimum. Finally, a simulation experiment from Shaoxing textile case is used to verify its efficiency and effectiveness.
Leveraging human decision making through the optimal management of centralized resources
Hyden, Paul; McGrath, Richard G.
2016-05-01
Combining results from mixed integer optimization, stochastic modeling and queuing theory, we will advance the interdisciplinary problem of efficiently and effectively allocating centrally managed resources. Academia currently fails to address this, as the esoteric demands of each of these large research areas limits work across traditional boundaries. The commercial space does not currently address these challenges due to the absence of a profit metric. By constructing algorithms that explicitly use inputs across boundaries, we are able to incorporate the advantages of using human decision makers. Key improvements in the underlying algorithms are made possible by aligning decision maker goals with the feedback loops introduced between the core optimization step and the modeling of the overall stochastic process of supply and demand. A key observation is that human decision-makers must be explicitly included in the analysis for these approaches to be ultimately successful. Transformative access gives warfighters and mission owners greater understanding of global needs and allows for relationships to guide optimal resource allocation decisions. Mastery of demand processes and optimization bottlenecks reveals long term maximum marginal utility gaps in capabilities.
Directory of Open Access Journals (Sweden)
Arjan P. Palstra
2015-01-01
Full Text Available Swimming exercise at optimal speed may optimize growth performance of yellowtail kingfish in a recirculating aquaculture system. Therefore, optimal swimming speeds (Uopt in m s-1 or body lengths s-1, BL s-1 were assessed and then applied to determine the effects of long-term forced and sustained swimming at Uopt on growth performance of juvenile yellowtail kingfish. Uopt was quantified in Blazka-type swim-tunnels for 145 mm, 206 mm and 311 mm juveniles resulting in values of: 1 0.70 m s-1 or 4.83 BL s-1, 2 0.82 m s-1 or 3.25 BL s-1 and 3 0.85 m s-1 or 2.73 BL s-1. Combined with literature data from larger fish, a relation of Uopt (BL s-1 = 234.07(BL-0.779 (R2= 0.9909 was established for this species. Yellowtail kingfish, either forced to perform sustained swimming exercise at an optimal speed of 2.46 BL s-1 (‘swimmers’ or allowed to perform spontaneous activity at low water flow (‘resters’ in a newly designed 3,600 L oval flume (with flow created by an impeller driven by an electric motor, were then compared. At the start of the experiment, ten fish were sampled representing the initial condition. After 18 days, swimmers (n= 23 showed a 92% greater increase in BL and 46% greater increase in BW as compared to resters (n= 23. As both groups were fed equal rations, feed conversion ratio (FCR for swimmers was 1.21 vs. 1.74 for resters. Doppler ultrasound imaging showed a statistically significant higher blood flow (31% in the ventral aorta of swimmers vs. resters (44 ± 3 mL min-1 vs. 34 ± 3 mL min-1, respectively, under anesthesia. Thus growth performance can be rapidly improved by optimal swimming, without larger feed investments.
Yao, Yong-Sheng; Han, Peng; Niu, Chang-Ying; Dong, Yong-Cheng; Gao, Xi-Wu; Cui, Jin-Jie; Desneux, Nicolas
2016-01-01
Top-down force is referred to arthropod pest management delivered by the organisms from higher trophic levels. In the context of prevalent adoption of transgenic Bt crops that produce insecticidal Cry proteins derived from Bacillus thuringiensis (Bt), it still remains elusive whether the top-down forces are affected by the insect-resistant traits that introduced into the Bt crops. We explored how Bt cotton affect the strength of top-down forces via arthropod natural enemies in regulating a non-target pest species, the cotton aphid Aphis gossypii Glover, using a comparative approach (i.e. Bt cotton vs. conventional cotton) under field conditions. To determine top-down forces, we manipulated predation/parasitism exposure of the aphid to their natural enemies using exclusion cages. We found that the aphid population growth was strongly suppressed by the dominant natural enemies including Coccinellids, spiders and Aphidiines parasitoids. Coccinellids, spiders and the assemblage of other arthropod natural enemies (mainly lacewings and Hemipteran bugs) are similarly abundant in both plots, but with the parasitoid mummies less abundant in Bt cotton plots compared to the conventional cotton plots. However, the lower abundance of parasitoids in Bt cotton plots alone did not translate into differential top-down control on A. gossypii populations compared to conventional ones. Overall, the top-down forces were equally strong in both plots. We conclude that transgenic Bt cotton does not disrupt the top-down forces regulating the cotton aphid in central China. PMID:27870914
Directory of Open Access Journals (Sweden)
M. Conradie
2004-02-01
Full Text Available Background and purpose: Physiotherapists frequently use central posterior-anterior (PA joint mobilization techniques for assessing and managing spinal disorders. Manual examination findings provide the basis for the selection of treatment techniques. From the literature it is evident that the level of reliability varies when physiotherapists perform different mobilization techniques. Repeatability of mobilization techniques is important for better physiotherapy management. The aim of the study was to determine whether experienced physiotherapists apply equal magnitude of force during a grade I central PA mobilisation technique on the cervical spine. Another aim was to determine the variation in the magnitude of forceapplied by each individual physiotherapist. Subjects: Sample of convenience, consisting of sixteen (n=16 selected qualified physiotherapists with experience inOrthopaedic Manual Therapy.Methods: A grade I central PA was performed on the Flexiforce TM sensors positioned on C6 of the same asymptomatic model to measure the applied magnitude of force. Two separate measurements, each lasting 30-seconds, were obtained.Results: The average maximum peak force applied by the majority of physiotherapists (87.5% was between 10.95gand 72g. The difference in the forces applied for the two measurements ranged between 0.64g and 24.4g. The BlandAltman scatterplot determined the mean of the difference between measurement one and two, calculated for the group, was zero. When comparing the two measurements, little variation was noted in the forces applied, as well as the coefficient of variation for each physiotherapist.Conclusion and Discussion: Current results demonstrated good intra-therapist and moderate to good inter-therapist repeatability. Further research is required to generalize results.
Development of devices for self-injection: using tribological analysis to optimize injection force
Directory of Open Access Journals (Sweden)
Lange J
2016-05-01
Full Text Available Jakob Lange, Leos Urbanek, Stefan BurrenYpsomed Delivery Systems, Ypsomed AG, Burgdorf, Switzerland Abstract: This article describes the use of analytical models and physical measurements to characterize and optimize the tribological behavior of pen injectors for self-administration of biopharmaceuticals. One of the main performance attributes of this kind of device is its efficiency in transmitting the external force applied by the user on to the cartridge inside the pen in order to effectuate an injection. This injection force characteristic is heavily influenced by the frictional properties of the polymeric materials employed in the mechanism. Standard friction tests are available for characterizing candidate materials, but they use geometries and conditions far removed from the actual situation inside a pen injector and thus do not always generate relevant data. A new test procedure, allowing the direct measurement of the coefficient of friction between two key parts of a pen injector mechanism using real parts under simulated use conditions, is presented. In addition to the absolute level of friction, the test method provides information on expected evolution of friction over lifetime as well as on expected consistency between individual devices. Paired with an analytical model of the pen mechanism, the frictional data allow the expected overall injection system force efficiency to be estimated. The test method and analytical model are applied to a range of polymer combinations with different kinds of lubrication. It is found that material combinations used without lubrication generally have unsatisfactory performance, that the use of silicone-based internal lubricating additives improves performance, and that the best results can be achieved with external silicone-based lubricants. Polytetrafluoroethylene-based internal lubrication and external lubrication are also evaluated but found to provide only limited benefits unless used in
Indian Academy of Sciences (India)
Izzet Karakurt
2014-10-01
In this paper, an optimization study was carried out for the cutting force (Fc) acting on circular diamond sawblades in rock sawing. The peripheral speed, traverse speed, cut depth and flow rate of cooling fluid were considered as operating variables and optimized by using Taguchi approach for the Fc. L16(44) orthogonal array was chosen for the experimental trials based on the operating variables and their levels. The signal-to-noise (S/N) ratios and the analysis of variance (ANOVA) were employed to determine optimum cutting conditions and significant operating variables, respectively. The Fc was also modelled based on the operating variables using regression analysis. The developed model was then verified using various statistical approaches. The results revealed that the operating variables of circular diamond sawblades can be precisely optimized by Taguchi approach for the Fc in rock sawing. The cut depth and peripheral speed were statistically determined as the significant operating variables affecting Fc. Furthermore, the modelling results showed that the proposed model can be effectively used for the prediction of Fc in practical applications.
Optimal Dividend and Capital Injection Strategies for a Risk Model under Force of Interest
Directory of Open Access Journals (Sweden)
Ying Fang
2013-01-01
Full Text Available As a generalization of the classical Cramér-Lundberg risk model, we consider a risk model including a constant force of interest in the present paper. Most optimal dividend strategies which only consider the processes modeling the surplus of a risk business are absorbed at 0. However, in many cases, negative surplus does not necessarily mean that the business has to stop. Therefore, we assume that negative surplus is not allowed and the beneficiary of the dividends is required to inject capital into the insurance company to ensure that its risk process stays nonnegative. For this risk model, we show that the optimal dividend strategy which maximizes the discounted dividend payments minus the penalized discounted capital injections is a threshold strategy for the case of the dividend payout rate which is bounded by some positive constant and the optimal injection strategy is to inject capitals immediately to make the company's assets back to zero when the surplus of the company becomes negative.
Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery
Energy Technology Data Exchange (ETDEWEB)
Gonzalez-Mira, E; Egea, M A; Garcia, M L [Department of Physical Chemistry, Faculty of Pharmacy, Institute of Nanoscience and Nanotechnology, University of Barcelona, Avenida Joan XXIII s/n, E-08028 Barcelona (Spain); Souto, E B [Faculty of Health Sciences, Fernando Pessoa University, Rua Carlos da Maia, Nr. 296, Office S.1, P-4200-150 Porto (Portugal); Calpena, A C, E-mail: eligonzalezmi@ub.edu [Department of Biopharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Barcelona, Avenida Joan XXIII s/n, E-08028 Barcelona (Spain)
2011-01-28
The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE ({approx}90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.
Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery
Gonzalez-Mira, E.; Egea, M. A.; Souto, E. B.; Calpena, A. C.; García, M. L.
2011-01-01
The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol® 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween® 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (~90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.
Predicting the optimal depth of left-sided central venous catheters in children.
Kim, H; Jeong, C-H; Byon, H-J; Shin, H K; Yun, T J; Lee, J-H; Park, Y-H; Kim, J-T
2013-10-01
The aim of this study was to predict the optimal depth for insertion of a left-sided central venous catheter in children. Using 3D chest computed tomography angiography, we measured the distance from a point where the internal jugular vein is at the superior border of the clavicle, and from a point where the subclavian vein is inferior to the anterior border of the clavicle, to the junction of the superior vena cava and the right atrium in 257 children. Linear regression analysis revealed that the distances correlated with age, weight and height. Simple formulae for the depth of a central venous catheter via the left internal jugular vein (0.07 × height (cm)) and the left subclavian vein (0.08 × height (cm)) were developed to predict placement of the central venous catheter tip at the junction of the superior vena cava with the right atrium. Using these fomulae, the proportion of catheter tips predicted to be correctly located was 98.5% (95% CI 96.8-100%) and 94.0% (95% CI 90.8-97.3%), respectively.
Directory of Open Access Journals (Sweden)
Dirk Reith
2013-09-01
Full Text Available Molecular modeling is an important subdomain in the field of computational modeling, regarding both scientific and industrial applications. This is because computer simulations on a molecular level are a virtuous instrument to study the impact of microscopic on macroscopic phenomena. Accurate molecular models are indispensable for such simulations in order to predict physical target observables, like density, pressure, diffusion coefficients or energetic properties, quantitatively over a wide range of temperatures. Thereby, molecular interactions are described mathematically by force fields. The mathematical description includes parameters for both intramolecular and intermolecular interactions. While intramolecular force field parameters can be determined by quantum mechanics, the parameterization of the intermolecular part is often tedious. Recently, an empirical procedure, based on the minimization of a loss function between simulated and experimental physical properties, was published by the authors. Thereby, efficient gradient-based numerical optimization algorithms were used. However, empirical force field optimization is inhibited by the two following central issues appearing in molecular simulations: firstly, they are extremely time-consuming, even on modern and high-performance computer clusters, and secondly, simulation data is affected by statistical noise. The latter provokes the fact that an accurate computation of gradients or Hessians is nearly impossible close to a local or global minimum, mainly because the loss function is flat. Therefore, the question arises of whether to apply a derivative-free method approximating the loss function by an appropriate model function. In this paper, a new Sparse Grid-based Optimization Workflow (SpaGrOW is presented, which accomplishes this task robustly and, at the same time, keeps the number of time-consuming simulations relatively small. This is achieved by an efficient sampling procedure
Using Maximal Isometric Force to Determine the Optimal Load for Measuring Dynamic Muscle Power
Spiering, Barry A.; Lee, Stuart M. C.; Mulavara, Ajitkumar P.; Bentley, Jason R.; Nash, Roxanne E.; Sinka, Joseph; Bloomberg, Jacob J.
2009-01-01
Maximal power output occurs when subjects perform ballistic exercises using loads of 30-50% of one-repetition maximum (1-RM). However, performing 1-RM testing prior to power measurement requires considerable time, especially when testing involves multiple exercises. Maximal isometric force (MIF), which requires substantially less time to measure than 1-RM, might be an acceptable alternative for determining the optimal load for power testing. PURPOSE: To determine the optimal load based on MIF for maximizing dynamic power output during leg press and bench press exercises. METHODS: Twenty healthy volunteers (12 men and 8 women; mean +/- SD age: 31+/-6 y; body mass: 72 +/- 15 kg) performed isometric leg press and bench press movements, during which MIF was measured using force plates. Subsequently, subjects performed ballistic leg press and bench press exercises using loads corresponding to 20%, 30%, 40%, 50%, and 60% of MIF presented in randomized order. Maximal instantaneous power was calculated during the ballistic exercise tests using force plates and position transducers. Repeated-measures ANOVA and Fisher LSD post hoc tests were used to determine the load(s) that elicited maximal power output. RESULTS: For the leg press power test, six subjects were unable to be tested at 20% and 30% MIF because these loads were less than the lightest possible load (i.e., the weight of the unloaded leg press sled assembly [31.4 kg]). For the bench press power test, five subjects were unable to be tested at 20% MIF because these loads were less than the weight of the unloaded aluminum bar (i.e., 11.4 kg). Therefore, these loads were excluded from analysis. A trend (p = 0.07) for a main effect of load existed for the leg press exercise, indicating that the 40% MIF load tended to elicit greater power output than the 60% MIF load (effect size = 0.38). A significant (p . 0.05) main effect of load existed for the bench press exercise; post hoc analysis indicated that the effect of
Nguyen, Q. H.; Choi, S. B.; Lee, Y. S.; Han, M. S.
2013-11-01
This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.
Wiegelmann, T; Inhester, B; Tadesse, T; Sun, X; Hoeksema, J T
2012-01-01
The SDO/HMI instruments provide photospheric vector magnetograms with a high spatial and temporal resolution. Our intention is to model the coronal magnetic field above active regions with the help of a nonlinear force-free extrapolation code. Our code is based on an optimization principle and has been tested extensively with semi-analytic and numeric equilibria and been applied before to vector magnetograms from Hinode and ground based observations. Recently we implemented a new version which takes measurement errors in photospheric vector magnetograms into account. Photospheric field measurements are often due to measurement errors and finite nonmagnetic forces inconsistent as a boundary for a force-free field in the corona. In order to deal with these uncertainties, we developed two improvements: 1.) Preprocessing of the surface measurements in order to make them compatible with a force-free field 2.) The new code keeps a balance between the force-free constraint and deviation from the photospheric field m...
Central and tensor components of three-nucleon forces in low-energy proton-deuteron scattering
Ishikawa, S; Iseri, Y
2003-01-01
Contributions of three-nucleon forces (3NF) to proton-deuteron scattering observables at energies below the deuteron breakup threshold are studied by solving the Faddeev equation that includes the Coulomb interaction. At E_p=3.0 MeV, we find that the central part of a two-pion exchange 3NF removes the discrepancy between measured cross sections and the calculated ones by two-nucleon forces, and improves the agreement with T_{22} experimental data. However, the tensor part of the 3NF fails in reproducing data of the analyzing power T_{21} by giving worse agreement between the measured and the calculated. Detailed examinations of scattering amplitudes suggest that a P-wave contribution in spin quartet tensor amplitudes has unsuitable sign for reproducing the T_{21} data.
Directory of Open Access Journals (Sweden)
Sysoiev Volodymyr
2013-01-01
Full Text Available Management of the state power structures’ organizational units for materiel and technical support requires the use of effective tools for supporting decisions, due to the complexity, interdependence, and dynamism of supply in the market economy. The corporate nature of power structures is of particular interest to centralized procurement management, as it provides significant advantages through coordination, eliminating duplication, and economy of scale. This article presents optimization models of the supply of state power structures’ organizational units with centralized procurement, for different levels of simulated materiel and technical support processes. The models allow us to find the most profitable options for state power structures’ organizational supply units in a centre-oriented logistics system in conditions of the changing needs, volume of allocated funds, and logistics costs that accompany the process of supply, by maximizing the provision level of organizational units with necessary material and technical resources for the entire planning period of supply by minimizing the total logistical costs, taking into account the diverse nature and the different priorities of organizational units and material and technical resources.
Directory of Open Access Journals (Sweden)
Mukesh Kumar
2015-09-01
Full Text Available A novel tannase producing bacterial strain was isolated from rhizospheric soil of Acacia species and identified as Klebsiella pneumoniae KP715242. A 3.25-fold increase in tannase production was achieved upon optimization with central composite design using response surface methodology. Four variables namely pH, temperature, incubation period, and agitation speed were used to optimize significant correlation between the effects of these variables on tannase production. A second-order polynomial was fitted to data and validated by ANOVA. The results showed a complex relationship between variables and response given that all factors were significant and could explain 99.6% of the total variation. The maximum production was obtained at 5.2 pH, 34.97 °C temperature, 103.34 rpm agitation speed and 91.34 h of incubation time. The experimental values were in good agreement with the predicted ones and the models were highly significant with a correlation coefficient (R2 of 0.99 and a highly significant F-value of 319.37.
2008-01-01
22 Accounting for these 30 aircraft plus the 24 F100-220A/E PAA realigned from Elmen- dorf AFB, a shortfall of 131 F100-220A/E PAA remains. Note...Management Division (ILMM), Centralized Intermediate Repair Facility CIRF Test Report, Washington, D.C.: Pentagon, June 2002. Hillestad, Richard J
Geometric derivation of the microscopic stress: A covariant central force decomposition
Torres-Sánchez, Alejandro; Vanegas, Juan M.; Arroyo, Marino
2016-08-01
We revisit the derivation of the microscopic stress, linking the statistical mechanics of particle systems and continuum mechanics. The starting point in our geometric derivation is the Doyle-Ericksen formula, which states that the Cauchy stress tensor is the derivative of the free-energy with respect to the ambient metric tensor and which follows from a covariance argument. Thus, our approach to define the microscopic stress tensor does not rely on the statement of balance of linear momentum as in the classical Irving-Kirkwood-Noll approach. Nevertheless, the resulting stress tensor satisfies balance of linear and angular momentum. Furthermore, our approach removes the ambiguity in the definition of the microscopic stress in the presence of multibody interactions by naturally suggesting a canonical and physically motivated force decomposition into pairwise terms, a key ingredient in this theory. As a result, our approach provides objective expressions to compute a microscopic stress for a system in equilibrium and for force-fields expanded into multibody interactions of arbitrarily high order. We illustrate the proposed methodology with molecular dynamics simulations of a fibrous protein using a force-field involving up to 5-body interactions.
Miocene orographic uplift forces rapid hydrological change in the southern central Andes
Rohrmann, Alexander; Sachse, Dirk; Mulch, Andreas; Pingel, Heiko; Tofelde, Stefanie; Alonso, Ricardo N.; Strecker, Manfred R.
2016-10-01
Rainfall in the central Andes associated with the South American Monsoon and the South American Low-Level Jet results from orographic effects on atmospheric circulation exerted by the Andean Plateau and the Eastern Cordillera. However, despite its importance for South American climate, no reliable records exist that allow decoding the evolution of thresholds and interactions between Andean topography and atmospheric circulation, especially regarding the onset of humid conditions in the inherently dry southern central Andes. Here, we employ multi-proxy isotope data of lipid biomarkers, pedogenic carbonates and volcanic glass from the Eastern Cordillera of NW Argentina and present the first long-term evapotranspiration record. We find that regional eco-hydrology and vegetation changes are associated with initiation of moisture transport via the South American Low-Level Jet at 7.6 Ma, and subsequent lateral growth of the orogen at 6.5 Ma. Our results highlight that topographically induced changes in atmospheric circulation patterns, not global climate change, were responsible for late Miocene environmental change in this part of the southern hemisphere. This suggests that mountain building over time fundamentally controlled habitat evolution along the central Andes.
OPTIMIZATION AND CHARACTERIZATION OF ELECTRON BEAM RESIST USING ATOMIC FORCE MICROSCOPY
Directory of Open Access Journals (Sweden)
- Sutikno
2012-01-01
Full Text Available Resis negatif ma-N 2403 dan 495 K PMMA memiliki resolusi yang baik untuk aplikasi litografi berkas elektron (EBL. Ketebalanresist optimal memainkan peran penting dalam paparan berkas elektron. Oleh karena itu, dalam penelitian ini, ketebalan darikedua resist yang dioptimalkan menggunakan spincoater dalam jangkauan laju spin 1000-6000 rpm. Semakin laju spin meningkat,ketebalan resist menurun juga. Morfologi permukaan resist dikarakterisasi dengan mikroskop gaya atom. Butir butir resist nampakpanjang. Dalam analisis AFM, permukaan profil resist negatif ma-N 2403 dan 495 K PMMA nampak seperti kerucut.Â Negative resist ma-N 2403 and 495 K PMMA have good resolution for electron beam lithography (EBL application. The optimumresist thickness plays significant role in e-beam exposure. Therefore, in this research, thicknesses of both resists were optimizedusing spincoater within spin speeds of 1000-6000 rpm. As spin speed increased, resist thickness decreased as well. Morphology ofresist surfaces were characterized using atomic force microscopy (AFM. Grains of resist show long grains. In AFM analyses,surface profiles of negative resist ma-N 2403 and 495 K PMMA show cone peaks.Keywords: e-beam resist; spincoater; e-beam lithography
Directory of Open Access Journals (Sweden)
Myeong Jin Ko
2015-11-01
Full Text Available In this study, the multi-objective optimization of an indirect forced-circulation solar water heating (SWH system was performed to obtain the optimal configuration that minimized the life cycle cost (LCC and maximized the life cycle net energy saving (LCES. An elitist non-dominated sorting genetic algorithm (NSGA-II was employed to obtain the Pareto optimal solutions of the multi-objective optimization. To incorporate the characteristics of practical SWH systems, operation-related decision variables as well as capacity-related decision variables were included. The proposed method was used to conduct a case study wherein the optimal configuration of the SWH system of an office building was determined. The case study results showed that the energy cost decreases linearly and the equipment cost increases more significantly as the LCES increases. However, the results also showed that it is difficult to identify the best solution among the Pareto optimal solutions using only the correlation between the corresponding objective function values. Furthermore, regression analysis showed that the energy and economic performances of the Pareto optimal solutions are significantly influenced by the ratio of the storage tank volume to the collector area (RVA. Therefore, it is necessary to simultaneously consider the trade-off and the effect of the RVA on the Pareto optimal solutions while selecting the best solution from among the optimal solutions.
Analysis of United States Air Forces Central Government Purchase Card Reachback Viability
2011-12-01
Kiser HQ ACC – A7/K Langley AFB, VA 7. Col Marvin Smith HQ AFCENT – A7 Shaw AFB, SC 8. Lt Col Timothy Hawkins Naval Postgraduate School...Colonel Marvin Smith – for providing the necessary resources for us to go on the PMA trip • Colonel Scott Kiser – for selecting us to accompany Maj...closest to the originating location of the supply chain, which is usually in the contiguous United States. USAFCENT, based out of Shaw Air Force Base
Application of the central composite design to optimize the preparation of novel micelles of harmine
Directory of Open Access Journals (Sweden)
Bei YY
2013-05-01
Full Text Available Yong-Yan Bei,1,* Xiao-Feng Zhou,2,3,* Ben-Gang You,1 Zhi-Qiang Yuan,1 Wei-Liang Chen,1 Peng Xia,1 Yang Liu,1 Yong Jin,4 Xiao-Juan Hu,1 Qiao-Ling Zhu,1 Chun-Ge Zhang,1 Xue-Nong Zhang,1 Liang Zhang5 1Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, People’s Republic of China; 2College of Radiological Medicine and Protection, Soochow University, Suzhou, People’s Republic of China; 3Changshu Hospital of Traditional Chinese Medicine, Changshu, People’s Republic of China; 4Invasive Technology Department, The Second Affiliated Hospital of Soochow University, Suzhou, People’s Republic of China; 5Department of Biopharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou, People’s Republic of China*These authors contributed equally to the paperAbstract: Lactose–palmitoyl–trimethyl–chitosan (Lac-TPCS, a novel amphipathic self-assembled polymer, was synthesized for administration of insoluble drugs to reduce their adverse effects. The central composite design was used to study the preparation technique of harmine (HM-loaded self-assembled micelles based on Lac-TPCS (Lac-TPCS/HM. Three preparation methods and single factors were screened, including solvent type, HM amount, hydration volume, and temperature. The optimal preparation technique was identified after investigating the influence of two independent factors, namely, HM amount and hydration volume, on four indexes, ie, encapsulation efficiency (EE, drug-loading amount (LD, particle size, and polydispersity index (PDI. Analysis of variance showed a high coefficient of determination of 0.916 to 0.994, thus ensuring a satisfactory adjustment of the predicted prescription. The maximum predicted values of the optimal prescription were 91.62%, 14.20%, 183.3 nm, and 0.214 for EE, LD, size, and PDI, respectively, when HM amount was 1.8 mg and hydration volume was 9.6 mL. HM-loaded micelles were successfully characterized by
Uhlig, Ralf; Frantz, Cathy; Fritsch, Andreas
2016-05-01
External receiver configurations are directly exposed to ambient wind. Therefore, a precise determination of the convective losses is a key factor in the prediction and evaluation of the efficiency of the solar absorbers. Based on several studies, the forced convective losses of external receivers are modeled using correlations for a roughened cylinder in a cross-flow of air. However at high wind velocities, the thermal efficiency measured during the Solar Two experiment was considerably lower than the efficiency predicted by these correlations. A detailed review of the available literature on the convective losses of external receivers has been made. Three CFD models of different level of detail have been developed to analyze the influence of the actual shape of the receiver and tower configuration, of the receiver shape and of the absorber panels on the forced convective heat transfer coefficients. The heat transfer coefficients deduced from the correlations have been compared to the results of the CFD simulations. In a final step the influence of both modeling approaches on the thermal efficiency of an external tubular receiver has been studied in a thermal FE model of the Solar Two receiver.
Pant, P; Dumka, U C; Sagar, R; Satheesh, S K; Moorthy, K K; Sagar, Ram
2006-01-01
Collocated measurements of the mass concentrations of aerosol black carbon (BC) and composite aerosols near the surface were carried out along with spectral aerosol optical depths (AODs) from a high altitude station, Manora Peak in Central Himalayas, during a comprehensive aerosol field campaign in December 2004. Despite being a pristine location in the Shivalik Ranges of Central Himalayas, and having a monthly mean AOD (at 500 nm) of 0.059 $\\pm$ 0.033 (typical to this site), total suspended particulate (TSP) concentration was in the range 15 - 40 micro g m^(-3) (mean value 27.1 $\\pm$ 8.3 micro g m^(-3)). Interestingly, aerosol BC had a mean concentration of 1.36 $\\pm$ 0.99 micro g m^(-3), contributed to ~5.0 $\\pm$ 1.3 % to the composite aerosol mass. This large abundance of BC is found to have linkages to the human activities in the adjoining valley and to the boundary layer dynamics. Consequently, the inferred single scattering albedo lies in the range of 0.87 to 0.94 (mean value 0.90 $\\pm$ 0.03), indicatin...
Aerosol radiative forcing efficiency in the UV-B region over central Argentina
Palancar, Gustavo G.; Olcese, Luis E.; Lanzaco, Bethania L.; Achad, Mariana; López, María Laura; Toselli, Beatriz M.
2016-07-01
AEROSOL Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer (MODIS) and global UV-B (280-315 nm) irradiance measurements and calculations were combined to investigate the effects of aerosol loading on the ultraviolet B radiation (UV-B) reaching the surface under cloudless conditions in Córdoba, Argentina. The aerosol radiative forcing (ARF) and the aerosol forcing efficiency (ARFE) were calculated for an extended period of time (2000-2013) at a ground-based monitoring site affected by different types and loading of aerosols. The ARFE was evaluated by using the aerosol optical depth (AOD) at 340 nm retrieved by AERONET at the Cordoba CETT site. The individual and combined effects of the single scattering albedo (SSA) and the solar zenith angle (SZA) on the ARFE were also analyzed. In addition, and for comparison purposes, the MODIS AOD at 550 nm was used as input in a machine learning method to better characterize the aerosol load at 340 nm and evaluate the ARFE retrieved from AOD satellite measurements. The ARFE at the surface calculated using AOD data from AERONET ranged from (-0.11 ± 0.01) to (-1.76 ± 0.20) Wm-2 with an average of -0.61 Wm-2; however, when using AOD data from MODIS (TERRA/AQUA satellites), it ranged from (-0.22 ± 0.03) to (-0.65 ± 0.07) Wm-2 with an average value of -0.43 Wm-2. At the same SZA and SSA, the maximum difference between ground and satellite-based was 0.22 Wm-2.
Lu, Li A; Ma, Ying S; Daverey, Achlesh; Lin, Jih G
2012-01-01
Carbofuran, one of the most toxic and biorefractory carbamate compounds, is widely used in insecticides in Taiwan (9-18% of total insecticides production per year). In the present study, a central composite design experiment was used to study the effect of photo-Fenton treatment on carbofuran solution and to optimize the process variables such as carbofuran concentration (1-100 mg L(-1)), H(2)O(2) dosage rate (0.25-6 mg L(-1) min(-1)) and Fe(3+) dosage (1-50 mg L(-1)), which influenced the efficiency of carbofuran degradation and mineralization. The results indicated that all the variables investigated in this study had significant roles in the degradation and mineralization of carbofuran in solution. The carbofuran degradation and mineralization efficiencies were increased with increase in H(2)O(2) dosage rate and Fe(3+) dosage, and with decrease in carbofuran concentration. Furthermore, optimum values of both H(2)O(2) dosage rate and Fe(3+) dosage were found to shift to higher values as carbofuran concentration increased. Based on the model obtained in this study, optimum H(2)O(2) dosage rate and Fe(3+) dosage were found to be 4 mg L(-1) min(-1) and 20 mg L(-1), respectively, for 51 mg L(-1) of carbofuran concentration. Under these conditions, carbofuran was completely removed within 30 min and coupled with 78% mineralization at the end of experiment.
Trajano, Gabriel S; Seitz, Laurent; Nosaka, Kasunori; Blazevich, Anthony J
2013-07-15
The purpose of the present research was to identify the contribution of central vs. peripheral factors to the force loss after passive muscle stretching. Thirteen men randomly performed both a 5-min constant-torque stretch of the plantar flexors on an isokinetic dynamometer and a resting condition on 2 separate days. The triceps surae electromyogram (EMG) was recorded simultaneously with plantar flexor isometric torque. Measures of central drive, including the EMG amplitude normalized to the muscle compound action potential amplitude (EMG/M), percent voluntary activation and first volitional wave amplitude, and measures of peripheral function, including the twitch peak torque, 20-to-80-Hz tetanic torque ratio and torque during 20-Hz stimulation preceded by a doublet, were taken before and immediately and 15 min after each condition. Peak torque (-15.7%), EMG/M (-8.2%), and both twitch (-9.4%) and 20-Hz peak torques (-11.5%) were reduced immediately after stretch but recovered by 15 min. There were strong correlations between the torque loss and the reductions in central drive parameters (r = 0.65-0.93). Torque recovery was also strongly correlated with the recovery in EMG/M and percent voluntary activation (r = 0.77-0.81). The moderate decreases in measures of peripheral function were not related to the torque loss or recovery. These results suggest that 1) central factors were strongly related to the torque reduction immediately after stretch and during torque recovery; and 2) the muscle's contractile capacity was moderately reduced, although these changes were not associated with the torque reduction, and changes in excitation-contraction coupling efficiency were not observed.
The ground state of medium-heavy nuclei with non central forces
Fabrocini, A
1997-01-01
We study microscopically the ground state properties of 16O and 40Ca nuclei within correlated basis function theory. A truncated version of the realistic Urbana v14 (U14) potential, without momentum dependent terms, is adopted with state dependent correlations having spin, isospin and tensor components. Fermi hypernetted chain integral equations and single operator chain approximation are used to evaluate one- and two-body densities and ground state energy. The results are in good agreement with the available variational MonteCarlo data, providing a first substantial check for the accuracy of the cluster expansion method with state dependent correlations. The finite nuclei treatment of non central interactions and correlations has, at least, the same level of accuracy as in infinite nuclear matter. The binding energy for the full U14+TNI interaction is computed, addressing its small momentum dependent contributions in local density approximation. The nuclei are underbound by about 1 MeV per nucleon. Further e...
Regional climate model assessment of the urban land-surface forcing over central Europe
Directory of Open Access Journals (Sweden)
P. Huszar
2014-07-01
Full Text Available For the purpose of qualifying and quantifying the climate impact of cities and urban surfaces in general on climate of central Europe, the surface parameterization in regional climate model RegCM4 has been extended with the Single Layer Urban Canopy Model (SLUCM. A set of experiments was performed over the period of 2005–2009 for central Europe, either without considering urban surfaces or with the SLUCM treatment. Results show a statistically significant impact of urbanized surfaces on temperature (up to 1.5 K increase in summer as well as on the boundary layer height (increases up to 50 m. Urbanization further influences surface wind with a winter decrease up to −0.6 m s−1, though both increases and decreases were detected in summer depending on the location relative to the cities and daytime (changes up to 0.3 m s−1. Urban surfaces significantly reduce evaporation and thus the humidity over the surface. This impacts the simulated summer precipitation rate, showing decrease over cities up to −2 mm day−1. Significant temperature increases are simulated over higher elevations as well, not only within the urban canopy layer. With the urban parameterization, the climate model better describes the diurnal temperature variation, reducing the cold afternoon and evening bias of RegCM4. Sensitivity experiments were carried out to quantify the response of the meteorological conditions to changes in the parameters specific to the urban environment such as street width, building height, albedo of the roofs and anthropogenic heat release. The results proved to be rather robust and the choice of the key SLUCM parameters impacts them only slightly (mainly temperature, boundary layer height and wind velocity. Statistically significant impacts are modeled not only over large urbanized areas, but the influence of the cities is also evident over rural areas without major urban surfaces. It is shown that this is the result of the combined effect of
Regional climate model assessment of the urban land-surface forcing over central Europe
Directory of Open Access Journals (Sweden)
P. Huszar
2014-11-01
Full Text Available For the purpose of qualifying and quantifying the climate impact of cities and urban surfaces in general on climate of central Europe, the surface parameterization in regional climate model RegCM4 has been extended with the Single-layer Urban Canopy Model (SLUCM. A set of experiments was performed over the period of 2005–2009 for central Europe, either without considering urban surfaces or with the SLUCM treatment. Results show a statistically significant impact of urbanized surfaces on temperature (up to 1.5 K increase in summer as well as on the boundary layer height (increases up to 50 m. Urbanization further influences surface wind with a winter decrease up to −0.6 m s−1, though both increases and decreases were detected in summer depending on the location relative to the cities and daytime (changes up to 0.3 m s−1. Urban surfaces significantly reduce the humidity over the surface. This impacts the simulated summer precipitation rate, showing a decrease over cities of up to −2 mm day−1. Significant temperature increases are simulated over higher altitudes as well, not only within the urban canopy layer. With the urban parameterization, the climate model better describes the diurnal temperature variation, reducing the cold afternoon and evening bias of RegCM4. Sensitivity experiments were carried out to quantify the response of the meteorological conditions to changes in the parameters specific to the urban environment, such as street width, building height, albedo of the roofs and anthropogenic heat release. The results proved to be rather robust and the choice of the key SLUCM parameters impacts them only slightly (mainly temperature, boundary layer height and wind velocity. Statistically significant impacts are modelled not only over large urbanized areas, but the influence of the cities is also evident over rural areas without major urban surfaces. It is shown that this is the result of the combined effect of the distant
DEFF Research Database (Denmark)
Ding, Tao; Jiang, Jiangfeng; Li, Cheng;
2017-01-01
Optimally dispatching Photovoltaic (PV) inverters is an efficient way to avoid overvoltage in active distribution networks, which may occur in the case of PV generation surplus load demand. Typically, the dispatching optimization objective is to identify critical PV inverters that have the most...... against any possible realization within the uncertain PV outputs. In addition, the conic relaxation-based branch flow formulation and second-order cone programming based column-and-constraint generation algorithm are employed to deal with the proposed robust optimization model. Case studies on a 33-bus...... significant impact on the network voltage level. Following, it ensures the optimal set-points of both active power and reactive power for the selected inverters, guaranteeing the entire system operating constraints (e.g., the network voltage magnitude) within reasonable ranges. However, the intermittent...
Directory of Open Access Journals (Sweden)
Hamid Tebassi
2016-01-01
Full Text Available Nickel based super alloys are excellent for several applications and mainly in structural components submitted to high temperatures owing to their high strength to weight ratio, good corrosion resistance and metallurgical stability such as in cases of jet engine and gas turbine components. The current work presents the experimental investigations of the cutting parameters effects (cutting speed, depth of cut and feed rate on the surface roughness, cutting force components, productivity and power consumption during dry conditions in straight turning using coated carbide tool. The mathematical models for output parameters have been developed using Box-Behnken design with 15 runs and Box-Cox transformation was used for improving normality. The results of the analysis have shown that the surface finish was statistically sensitive to the feed rate and cutting speed with the contribution of 43.58% and 23.85% respectively, while depth of cut had the greatest effect on the evolution of cutting force components with the contribution of 79.87% for feed force, 66.92% for radial force and 66.26% for tangential force. Multi-objective optimization procedure allowed minimizing roughness Ra, cutting forces and power consumption and maximizing material removal rate using desirability approach.
Ghose, Arup K; Herbertz, Torsten; Hudkins, Robert L; Dorsey, Bruce D; Mallamo, John P
2012-01-18
The central nervous system (CNS) is the major area that is affected by aging. Alzheimer's disease (AD), Parkinson's disease (PD), brain cancer, and stroke are the CNS diseases that will cost trillions of dollars for their treatment. Achievement of appropriate blood-brain barrier (BBB) penetration is often considered a significant hurdle in the CNS drug discovery process. On the other hand, BBB penetration may be a liability for many of the non-CNS drug targets, and a clear understanding of the physicochemical and structural differences between CNS and non-CNS drugs may assist both research areas. Because of the numerous and challenging issues in CNS drug discovery and the low success rates, pharmaceutical companies are beginning to deprioritize their drug discovery efforts in the CNS arena. Prompted by these challenges and to aid in the design of high-quality, efficacious CNS compounds, we analyzed the physicochemical property and the chemical structural profiles of 317 CNS and 626 non-CNS oral drugs. The conclusions derived provide an ideal property profile for lead selection and the property modification strategy during the lead optimization process. A list of substructural units that may be useful for CNS drug design was also provided here. A classification tree was also developed to differentiate between CNS drugs and non-CNS oral drugs. The combined analysis provided the following guidelines for designing high-quality CNS drugs: (i) topological molecular polar surface area of <76 Å(2) (25-60 Å(2)), (ii) at least one (one or two, including one aliphatic amine) nitrogen, (iii) fewer than seven (two to four) linear chains outside of rings, (iv) fewer than three (zero or one) polar hydrogen atoms, (v) volume of 740-970 Å(3), (vi) solvent accessible surface area of 460-580 Å(2), and (vii) positive QikProp parameter CNS. The ranges within parentheses may be used during lead optimization. One violation to this proposed profile may be acceptable. The
Institute of Scientific and Technical Information of China (English)
YAO Xin-feng; YAO Xia; TIAN Yong-chao; NI Jun; LIU Xiao-jun; CAO Wei-xing; ZHU Yan
2013-01-01
Plant nitrogen (N) uptake is a good indicator of cropNstatus. In this study, a new method was designed to determine the central wavelength, optimal bandwidth and vegetation indices for predicting plantNuptake (gNm-2) in winter wheat (Triticum aestivum L.). The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years, eco-sites, varieties,Nrates, sowing dates, and densities. The plantNuptake index (PNUI) based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index, and a linear model was developed with R2 of 0.870 and RMSE of 1.546 gNm-2 for calibration, and R2 of 0.834, RMSE of 1.316 gNm-2, slope of 0.934, and intercept of 0.001 for validation. Then, the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion. The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index. These findings are important for prediction and diagnosis of plantNuptake more precise and accurate in crop management.
Heidari, Behzad Shiroud; Oliaei, Erfan; Shayesteh, Hadi; Davachi, Seyed Mohammad; Hejazi, Iman; Seyfi, Javad; Bahrami, Mozhgan; Rashedi, Hamid
2017-01-01
In this study, injection molding of three poly lactic acid (PLA) based bone screws was simulated and optimized through minimizing the shrinkage and warpage of the bone screws. The optimization was carried out by investigating the process factors such as coolant temperature, mold temperature, melt temperature, packing time, injection time, and packing pressure. A response surface methodology (RSM), based on the central composite design (CCD), was used to determine the effects of the process factors on the PLA based bone screws. Upon applying the method of maximizing the desirability function, optimization of the factors gave the lowest warpage and shrinkage for nanocomposite PLA bone screw (PLA9). Moreover, PLA9 has the greatest desirability among the selected materials for bone screw injection molding. Meanwhile, a finite element analysis (FE analysis) was also performed to determine the force values and concentration points which cause yielding of the screws under certain conditions. The Von-Mises stress distribution showed that PLA9 screw is more resistant against the highest loads as compared to the other ones. Finally, according to the results of injection molding simulations, the design of experiments (DOE) and structural analysis, PLA9 screw is recommended as the best candidate for the production of biomedical materials among all the three types of screws.
Semenov, V. A.; Latif, M.
2014-12-01
The early 21st century was marked by several severe winters over Central Eurasia linked to a blocking anti-cyclone centered south of the Barents Sea (BS). The increased occurrence of such anomalously cold winters coincided with a strong reduction of winter Arctic sea ice cover (ASIC), especially in the BS where sea ice area exhibited a step-like decline in 2005, suggesting a possible connection. To study the possible link we performed simulations with a high-resolution global atmospheric general circulation model forced by a set of multi-year sea ice anomalies observed during the last decades. The regional circulation response to reduced ASIC in 2005-2012 exhibits a statistically significant anti-cyclonic surface pressure anomaly and a surface temperature response similar to that observed. The results suggest that the recent BS sea ice reduction may have been responsible for the recent anomalously cold winters in Central Eurasia. Furthermore, a positive sea ice anomaly in the late 1960s associated with negative phase of the North Atlantic Oscillation also results in a similar anti-cyclonic anomaly and a cooling over the continent in the model. This implies that the atmospheric circulation response to sea ice anomalies during the period of modern sea ice decline can be essentially non-linear, both with respect to amplitude and pattern.
Vuppalapati, Lavakumar; Cherukuri, Sowmya; Neeli, Vijaykumar; Yeragamreddy, Padmanabha Reddy; Kesavan, Bhaskar Reddy
2016-01-01
The objective of the present research is to prepare stable nano suspensions of Valsartan (VAL) with high solubility and dissolution. VAL is an orally administered anti-hypertensive drug with lower bio-availability of 25%, this is attributed to its lower aqueous solubility (0.082 mg/ml). VAL nano suspensions were prepared by using a bottom-up precipitation technique using five level full factorial central composite design (CCD). The optimized nano formulations NS21, NS22, NS23 showed the particle size of 268.42±8.99, 288.3±11.32, 293.46±6.92 nm, zeta potential of 20.89±0.79, 26.01 ±1.02, 21.34±0.43 mVs and the dissolution efficiency of 93.10±1.459, 91.84±1.419, 89.47±0.644 % respectively. SEM & AFM studies represent the formation of fine irregularly shaped particles with smooth surfaces on nanosization. X-rd studies confirmed the physical state conversion of crystalline drug into amorphous form. Drug excipient compatibility was studied using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The investigation pragmatic the solubility and dissolution efficiency of VAL in nanosuspension was significantly higher when compared with its pure form. Finally, it is concluded that, nanosuspension approach could be an ideal, promising approach to increase the solubility and dissolution of BCS-II drugs like Valsartan.
Tarlak, Fatih; Sadıkoğlu, Hasan; Çakır, Tunahan
2014-07-29
Prediction of intracellular metabolic fluxes based on optimal biomass assumption is a well-known computational approach. While there has been a significant emphasis on the optimality, cellular flexibility, the co-occurrence of suboptimal flux distributions in a microbial population, has hardly been considered in the related computational methods. We have implemented a flexibility-incorporated optimization framework to calculate intracellular fluxes based on a few extracellular measurement constraints. Taking into account slightly suboptimal flux distributions together with a dual-optimality framework (maximization of the growth rate followed by the minimization of the total enzyme amount) we were able to show the positive effect of incorporating flexibility and minimal enzyme consumption on the better prediction of intracellular fluxes of central carbon metabolism of two microorganisms: E. coli and S. cerevisiae.
Optimizing Protein-Protein van der Waals Interactions for the AMBER ff9x/ff12 Force Field.
Chapman, Dail E; Steck, Jonathan K; Nerenberg, Paul S
2014-01-14
The quality of molecular dynamics (MD) simulations relies heavily on the accuracy of the underlying force field. In recent years, considerable effort has been put into developing more accurate dihedral angle potentials for MD force fields, but relatively little work has focused on the nonbonded parameters, many of which are two decades old. In this work, we assess the accuracy of protein-protein van der Waals interactions in the AMBER ff9x/ff12 force field. Across a test set of 44 neat organic liquids containing the moieties present in proteins, we find root-mean-square (RMS) errors of 1.26 kcal/mol in enthalpy of vaporization and 0.36 g/cm(3) in liquid densities. We then optimize the van der Waals radii and well depths for all of the relevant atom types using these observables, which lowers the RMS errors in enthalpy of vaporization and liquid density of our validation set to 0.59 kcal/mol (53% reduction) and 0.019 g/cm(3) (46% reduction), respectively. Limitations in our parameter optimization were evident for certain atom types, however, and we discuss the implications of these observations for future force field development.
Ooe, Hiroaki; Fujii, Mikihiro; Tomitori, Masahiko; Arai, Toyoko
2016-02-01
High-Q factor retuned fork (RTF) force sensors made from quartz tuning forks, and the electric circuits for the sensors, were evaluated and optimized to improve the performance of non-contact atomic force microscopy (nc-AFM) performed under ultrahigh vacuum (UHV) conditions. To exploit the high Q factor of the RTF sensor, the oscillation of the RTF sensor was excited at its resonant frequency, using a stray capacitance compensation circuit to cancel the excitation signal leaked through the stray capacitor of the sensor. To improve the signal-to-noise (S/N) ratio in the detected signal, a small capacitor was inserted before the input of an operational (OP) amplifier placed in an UHV chamber, which reduced the output noise from the amplifier. A low-noise, wideband OP amplifier produced a superior S/N ratio, compared with a precision OP amplifier. The thermal vibrational density spectra of the RTF sensors were evaluated using the circuit. The RTF sensor with an effective spring constant value as low as 1000 N/m provided a lower minimum detection limit for force differentiation. A nc-AFM image of a Si(111)-7 × 7 surface was produced with atomic resolution using the RTF sensor in a constant frequency shift mode; tunneling current and energy dissipation images with atomic resolution were also simultaneously produced. The high-Q factor RTF sensor showed potential for the high sensitivity of energy dissipation as small as 1 meV/cycle and the high-resolution analysis of non-conservative force interactions.
Energy Technology Data Exchange (ETDEWEB)
Azizi, Mohamed Walid; Belhadi, Salim; Yallese, Mohamed Athmane [Univ. of Guelma, Guelma (Algeria); Mabrouki, Tarek; Rigal, Jean Francois [Univ. of Lyon, Lyon (France)
2012-12-15
An experimental investigation was conducted to analyze the effect of cutting parameters (cutting speed, feed rate and depth of cut) and workpiece hardness on surface roughness and cutting force components. The finish hard turning of AISI 52100 steel with coated Al2O3 + TiC mixed ceramic cutting tools was studied. The planning of experiment were based on Taguchi's L27 orthogonal array. The response table and analysis of variance (ANOVA) have allowed to check the validity of linear regression model and to determine the significant parameters affecting the surface roughness and cutting forces. The statistical analysis reveals that the feed rate, workpiece hardness and cutting speed have significant effects in reducing the surface roughness; whereas the depth of cut, workpiece hardness and feed rate are observed to have a statistically significant impact on the cutting force components than the cutting speed. Consequently, empirical models were developed to correlate the cutting parameters and workpiece hardness with surface roughness and cutting forces. The optimum machining conditions to produce the lowest surface roughness with minimal cutting force components under these experimental conditions were searched using desirability function approach for multiple response factors optimization. Finally, confirmation experiments were performed to verify the pertinence of the developed empirical models.
Directory of Open Access Journals (Sweden)
J Lucas McKay
Full Text Available Optimality principles have been proposed as a general framework for understanding motor control in animals and humans largely based on their ability to predict general features movement in idealized motor tasks. However, generalizing these concepts past proof-of-principle to understand the neuromechanical transformation from task-level control to detailed execution-level muscle activity and forces during behaviorally-relevant motor tasks has proved difficult. In an unrestrained balance task in cats, we demonstrate that achieving task-level constraints center of mass forces and moments while minimizing control effort predicts detailed patterns of muscle activity and ground reaction forces in an anatomically-realistic musculoskeletal model. Whereas optimization is typically used to resolve redundancy at a single level of the motor hierarchy, we simultaneously resolved redundancy across both muscles and limbs and directly compared predictions to experimental measures across multiple perturbation directions that elicit different intra- and interlimb coordination patterns. Further, although some candidate task-level variables and cost functions generated indistinguishable predictions in a single biomechanical context, we identified a common optimization framework that could predict up to 48 experimental conditions per animal (n = 3 across both perturbation directions and different biomechanical contexts created by altering animals' postural configuration. Predictions were further improved by imposing experimentally-derived muscle synergy constraints, suggesting additional task variables or costs that may be relevant to the neural control of balance. These results suggested that reduced-dimension neural control mechanisms such as muscle synergies can achieve similar kinetics to the optimal solution, but with increased control effort (≈2× compared to individual muscle control. Our results are consistent with the idea that hierarchical, task
Astumian, R Dean
2015-01-20
A simple model for a chemically driven molecular walker shows that the elastic energy stored by the molecule and released during the conformational change known as the power-stroke (i.e., the free-energy difference between the pre- and post-power-stroke states) is irrelevant for determining the directionality, stopping force, and efficiency of the motor. Further, the apportionment of the dependence on the externally applied force between the forward and reverse rate constants of the power-stroke (or indeed among all rate constants) is irrelevant for determining the directionality, stopping force, and efficiency of the motor. Arguments based on the principle of microscopic reversibility demonstrate that this result is general for all chemically driven molecular machines, and even more broadly that the relative energies of the states of the motor have no role in determining the directionality, stopping force, or optimal efficiency of the machine. Instead, the directionality, stopping force, and optimal efficiency are determined solely by the relative heights of the energy barriers between the states. Molecular recognition--the ability of a molecular machine to discriminate between substrate and product depending on the state of the machine--is far more important for determining the intrinsic directionality and thermodynamics of chemo-mechanical coupling than are the details of the internal mechanical conformational motions of the machine. In contrast to the conclusions for chemical driving, a power-stroke is very important for the directionality and efficiency of light-driven molecular machines and for molecular machines driven by external modulation of thermodynamic parameters.
Directory of Open Access Journals (Sweden)
Peng Han
Full Text Available The cotton aphid Aphis gossypii Glover is the main aphid pest in cotton fields in the Yangtze River Valley Cotton-planting Zone (YRZ in central China. Various natural enemies may attack the cotton aphid in Bt cotton fields but no studies have identified potential specific top-down forces that could help manage this pest in the YRZ in China. In order to identify possibilities for managing the cotton aphid, we monitored cotton aphid population dynamics and identified the effect of natural enemies on cotton aphid population growth using various exclusion cages in transgenic Cry1Ac (Bt+CpTI (Cowpea trypsin inhibitor cotton field in 2011. The aphid population growth in the open field (control was significantly lower than those protected or restricted from exposure to natural enemies in the various exclusion cage types tested. The ladybird predator Propylaea japonica Thunberg represented 65% of Coccinellidae predators, and other predators consisted mainly of syrphids (2.1% and spiders (1.5%. The aphid parasitoids Aphidiines represented 76.7% of the total count of the natural enemy guild (mainly Lysiphlebia japonica Ashmead and Binodoxys indicus Subba Rao & Sharma. Our results showed that P. japonica can effectively delay the establishment and subsequent population growth of aphids during the cotton growing season. Aphidiines could also reduce aphid density although their impact may be shadowed by the presence of coccinellids in the open field (likely both owing to resource competition and intraguild predation. The implications of these results are discussed in a framework of the compatibility of transgenic crops and top-down forces exerted by natural enemy guild.
Han, Peng; Niu, Chang-ying; Desneux, Nicolas
2014-01-01
The cotton aphid Aphis gossypii Glover is the main aphid pest in cotton fields in the Yangtze River Valley Cotton-planting Zone (YRZ) in central China. Various natural enemies may attack the cotton aphid in Bt cotton fields but no studies have identified potential specific top-down forces that could help manage this pest in the YRZ in China. In order to identify possibilities for managing the cotton aphid, we monitored cotton aphid population dynamics and identified the effect of natural enemies on cotton aphid population growth using various exclusion cages in transgenic Cry1Ac (Bt)+CpTI (Cowpea trypsin inhibitor) cotton field in 2011. The aphid population growth in the open field (control) was significantly lower than those protected or restricted from exposure to natural enemies in the various exclusion cage types tested. The ladybird predator Propylaea japonica Thunberg represented 65% of Coccinellidae predators, and other predators consisted mainly of syrphids (2.1%) and spiders (1.5%). The aphid parasitoids Aphidiines represented 76.7% of the total count of the natural enemy guild (mainly Lysiphlebia japonica Ashmead and Binodoxys indicus Subba Rao & Sharma). Our results showed that P. japonica can effectively delay the establishment and subsequent population growth of aphids during the cotton growing season. Aphidiines could also reduce aphid density although their impact may be shadowed by the presence of coccinellids in the open field (likely both owing to resource competition and intraguild predation). The implications of these results are discussed in a framework of the compatibility of transgenic crops and top-down forces exerted by natural enemy guild.
Directory of Open Access Journals (Sweden)
Kausrud Kyrre
2010-08-01
Full Text Available Abstract Background Human cases of plague (Yersinia pestis infection originate, ultimately, in the bacterium's wildlife host populations. The epidemiological dynamics of the wildlife reservoir therefore determine the abundance, distribution and evolution of the pathogen, which in turn shape the frequency, distribution and virulence of human cases. Earlier studies have shown clear evidence of climatic forcing on contemporary plague abundance in rodents and humans. Results We find that high-resolution palaeoclimatic indices correlate with plague prevalence and population density in a major plague host species, the great gerbil (Rhombomys opimus, over 1949-1995. Climate-driven models trained on these data predict independent data on human plague cases in early 20th-century Kazakhstan from 1904-1948, suggesting a consistent impact of climate on large-scale wildlife reservoir dynamics influencing human epidemics. Extending the models further back in time, we also find correspondence between their predictions and qualitative records of plague epidemics over the past 1500 years. Conclusions Central Asian climate fluctuations appear to have had significant influences on regional human plague frequency in the first part of the 20th century, and probably over the past 1500 years. This first attempt at ecoepidemiological reconstruction of historical disease activity may shed some light on how long-term plague epidemiology interacts with human activity. As plague activity in Central Asia seems to have followed climate fluctuations over the past centuries, we may expect global warming to have an impact upon future plague epidemiology, probably sustaining or increasing plague activity in the region, at least in the rodent reservoirs, in the coming decades. See commentary: http://www.biomedcentral.com/1741-7007/8/108
Kahlen, Jens; Salimi, Leila; Sulpizi, Marialore; Peter, Christine; Donadio, Davide
2014-04-10
Many well-established classical biomolecular force fields, fitted on the solvation properties of single ions, do not necessarily describe all the details of ion pairing accurately, especially for complex polyatomic ions. Depending on the target application, it might not be sufficient to reproduce the thermodynamics of ion pairing, but it may also be necessary to correctly capture structural details, such as the coordination mode. In this work, we analyzed how classical force fields can be optimized to yield a realistic description of these different aspects of ion pairing. Given the prominent role of the interactions of negatively charged amino-acid side chains and divalent cations in many biomolecular systems, we chose calcium acetate as a benchmark system to devise a general optimization strategy that we applied to two popular force fields, namely, GROMOS and OPLS-AA. Using experimental association constants and first-principles molecular dynamics simulations as a reference, we found that small modifications of the van der Waals ion-ion interaction parameters allow a systematic improvement of the essential thermodynamic and structural properties of ion pairing.
Hart, Katarina; Foloppe, Nicolas; Baker, Christopher M; Denning, Elizabeth J; Nilsson, Lennart; Mackerell, Alexander D
2012-01-10
The B-form of DNA can populate two different backbone conformations: BI and BII, defined by the difference between the torsion angles ε and ζ (BI = ε-ζ 0). BI is the most populated state, but the population of the BII state, which is sequence dependent, is significant and accumulating evidence shows that BII affects the overall structure of DNA, and thus influences protein-DNA recognition. This work presents a reparametrization of the CHARMM27 additive nucleic acid force field to increase the sampling of the BII form in MD simulations of DNA. In addition, minor modifications of sugar puckering were introduced to facilitate sampling of the A form of DNA under the appropriate environmental conditions. Parameter optimization was guided by quantum mechanical data on model compounds, followed by calculations on several DNA duplexes in the condensed phase. The selected optimized parameters were then validated against a number of DNA duplexes, with the most extensive tests performed on the EcoRI dodecamer, including comparative calculations using the Amber Parm99bsc0 force field. The new CHARMM model better reproduces experimentally observed sampling of the BII conformation, including sampling as a function of sequence. In addition, the model reproduces the A form of the 1ZF1 duplex in 75 % ethanol, and yields a stable Z-DNA conformation of duplex (GTACGTAC) in its crystal environment. The resulting model, in combination with a recent reoptimization of the CHARMM27 force field for RNA, will be referred to as CHARMM36.
Shamarokov, A. S.; Zorin, V. M.; Dai, Fam Kuang
2016-03-01
At the current stage of development of nuclear power engineering, high demands on nuclear power plants (NPP), including on their economy, are made. In these conditions, improving the quality of NPP means, in particular, the need to reasonably choose the values of numerous managed parameters of technological (heat) scheme. Furthermore, the chosen values should correspond to the economic conditions of NPP operation, which are postponed usually a considerable time interval from the point of time of parameters' choice. The article presents the technique of optimization of controlled parameters of the heat circuit of a steam turbine plant for the future. Its particularity is to obtain the results depending on a complex parameter combining the external economic and operating parameters that are relatively stable under the changing economic environment. The article presents the results of optimization according to this technique of the minimum temperature driving forces in the surface heaters of the heat regeneration system of the steam turbine plant of a K-1200-6.8/50 type. For optimization, the collector-screen heaters of high and low pressure developed at the OAO All-Russia Research and Design Institute of Nuclear Power Machine Building, which, in the authors' opinion, have the certain advantages over other types of heaters, were chosen. The optimality criterion in the task was the change in annual reduced costs for NPP compared to the version accepted as the baseline one. The influence on the decision of the task of independent variables that are not included in the complex parameter was analyzed. An optimization task was decided using the alternating-variable descent method. The obtained values of minimum temperature driving forces can guide the design of new nuclear plants with a heat circuit, similar to that accepted in the considered task.
Optimization of the Forcing Term for the Solution of Two-Point Boundary Value Problems
Directory of Open Access Journals (Sweden)
Gianni Arioli
2013-01-01
by standard methods of constrained optimization, for example, with Lagrange multipliers. We provide an application of this algorithm to the planar restricted three body problem in order to study the planning of low-thrust transfer orbits.
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The magnetic force acting on workpieee to be machined plays a significantly important role in magnetic abrasive polishing process.But in a case of polishing nonferrous materials,the strength of magnetic force is very low and it leads lower polishing efficiency.The magnesium alloy that has superior mechanical properties for industrial application such as a lightweight and high specific strength is one of the most famous nonferrous materials.An improving strategy of the magnetic force for me AZ31 magnesium alloy installed with a permanent magnet was proposed and experimental verification Was carded out.For the proposed strategy,the effect of process parameters on the surface roughness of the AZ31 magnesium alloy Was evaluated by a design of experimental method.
Central bank balance sheet concerns and credible optimal escape from the Liquidity trap
Mendes, Arthur Galego
2001-01-01
I show that when a central bank is financially independent from the treasury and has balance sheet concerns, an increase in the size or a change in the composition of the central bank's balance sheet (quantitative easing) can serve as a commitment device in a liquidity trap scenario. In particular, when the short-term interest rate is up against the zero lower bound, an open market operation by the central bank that involves purchases of long-term bonds can help mitigate the ...
Beget, J. E.
1993-01-01
Continuous marine and ice-core proxy climate records indicate that the Earth's orbital geometry modulates long-term changes. Until recently, little direct evidence has been available to demonstrate correlations between Milankovitch cycles and large-scale terrestrial landforms produced during worldwide glaciations. In central Alaska large areas of loess and sand fill valleys and basins near major outwash streams. The streams themselves are bordered by sets of outwash terraces, and the terraces grade up valley into sets of moraines. The discovery of the Stampede tephra (approximately 175,000 yr ago) reworked within push moraines of the Lignite Creek glaciation suggests that this event correlates with the glaciation of marine isotope stage 6. A new occurrence of the Old Crow tephra (approximately 140,000 yr ago) on the surface of the oldest outwash terrace of the Tanana River, correlated with Delta glaciation, suggests this event also occurred at this time. The penultimate Healy glaciation apparently correlates with marine isotope stage 4, while radiocarbon dates indicate the latest Pleistocene moraines correlate with marine isotope stage 2. Recognition of the importance of orbital forcing to the cyclical formation of glacial landforms and landscapes can help in interpretations of remotely sensed glacial and proglacial land forms.
Kalyuzhnyi, Y V; Marshall, B D; Chapman, W G; Cummings, P T
2013-07-28
We propose a second-order version of the resummed thermodynamic perturbation theory for patchy colloidal models with arbitrary number of multiply bondable patches. The model is represented by the hard-sphere fluid system with several attractive patches on the surface and resummation is carried out to account for blocking effects, i.e., when the bonding of a particle restricts (blocks) its ability to bond with other particles. The theory represents an extension of the earlier proposed first order resummed thermodynamic perturbation theory for central force associating potential and takes into account formation of the rings of the particles. In the limiting case of singly bondable patches (total blockage), the theory reduces to Wertheim thermodynamic perturbation theory for associating fluids. Closed-form expressions for the Helmholtz free energy, pressure, internal energy, and chemical potential of the model with an arbitrary number of equivalent doubly bondable patches are derived. Predictions of the theory for the model with two patches appears to be in a very good agreement with predictions of new NVT and NPT Monte Carlo simulations, including the region of strong association.
Elking, Dennis M
2016-08-15
New equations for torque and atomic force are derived for use in flexible molecule force fields with atomic multipoles. The expressions are based on Cartesian tensors with arbitrary multipole rank. The standard method for rotating Cartesian tensor multipoles and calculating torque is to first represent the tensor with n indexes and 3(n) redundant components. In this work, new expressions for directly rotating the unique (n + 1)(n + 2)/2 Cartesian tensor multipole components Θpqr are given by introducing Cartesian tensor rotation matrix elements X(R). A polynomial expression and a recursion relation for X(R) are derived. For comparison, the analogous rotation matrix for spherical tensor multipoles are the Wigner functions D(R). The expressions for X(R) are used to derive simple equations for torque and atomic force. The torque and atomic force equations are applied to the geometry optimization of small molecule crystal unit cells. In addition, a discussion of computational efficiency as a function of increasing multipole rank is given for Cartesian tensors. © 2016 Wiley Periodicals, Inc.
Optimization of the Chin Bar of a Composite-Shell Helmet to Mitigate the Upper Neck Force
Farajzadeh Khosroshahi, S.; Galvanetto, U.; Ghajari, M.
2016-11-01
The chin bar of motorcycle full-face helmets is the most likely region of the helmet to sustain impacts during accidents, with a large percentage of these impacts leading to basilar skull fracture. Currently, helmet chin bars are designed to mitigate the peak acceleration at the centre of gravity of isolated headforms, as required by standards, but they are not designed to mitigate the neck force, which is probably the cause of basilar skull fracture, a type of head injury that can lead to fatalities. Here we test whether it is possible to increase the protection of helmet chin bars while meeting standard requirements. Fibre-reinforced composite shells are commonly used in helmets due to their lightweight and energy absorption characteristics. We optimize the ply orientation of a chin bar made of fibre-reinforced composite layers for reduction of the neck force in a dummy model using a computational approach. We use the finite element model of a human head/neck surrogate and measure the neck axial force, which has been shown to be correlated with the risk of basilar skull fracture. The results show that by varying the orientation of the chin bar plies, thus keeping the helmet mass constant, the neck axial force can be reduced by approximately 30% while ensuring that the helmet complies with the impact attenuation requirements prescribed in helmet standards.
Rengifo, Carlos; Aoustin, Yannick; Plestan, Franck; Chevallereau, Christine
2010-04-01
In this paper, a new neuromusculoskeletal simulation strategy is proposed. It is based on a cascade control approach with an inner muscular-force control loop and an outer joint-position control loop. The originality of the work is located in the optimization criterion used to distribute forces between synergistic and antagonistic muscles. The cost function and the inequality constraints depend on an estimation of the muscle fiber length and its time derivative. The advantages of a such criterion are exposed by theoretical analysis and numerical tests. The simulation model used in the numerical tests consists in an anthropomorphic arm model composed by two joints and six muscles. Each muscle is modeled as a second-order dynamical system including activation and contraction dynamics. Contraction dynamics is represented using a classical Hill's model.
DEFF Research Database (Denmark)
Markus, D.; Ferri, Francesco; Wüchner, R.
2015-01-01
that focuses on differences in load curves resulting from 2D and 3D flows. It is shown that the major trends predicted by the numerical simulations are also captured in the experiment, highlighting the potential of CFD as a powerful tool for shape optimization studies. The overall aim of the paper...... variations of the structure on the resulting horizontal forces. Steady current conditions, dynamic loading due to waves, and combined wave–current scenarios are considered. A clear focus is put on simplicity and reproducibility, allowing for efficient testing of related methods and codes. This is achieved...... by defining a simple test geometry, altered in one design variable only, and by designing the test case such that a two dimensional analysis of the flow fields is possible. The force sensitivities to changes in the geometry are determined both numerically and experimentally for a great bandwidth of different...
Optimization of Process Parameters of Edge Robotic Deburring with Force Control
Burghardt, A.; Szybicki, D.; Kurc, K.; Muszyńska, M.
2016-12-01
The issues addressed in the paper present a part of the scientific research conducted within the framework of the automation of the aircraft engine part manufacturing processes. The results of the research presented in the article provided information in which tolerances while using a robotic control station with the option of force control we can make edge deburring.
Directory of Open Access Journals (Sweden)
Sridhar Ranganathan
2010-04-01
Full Text Available Computational procedures for predicting metabolic interventions leading to the overproduction of biochemicals in microbial strains are widely in use. However, these methods rely on surrogate biological objectives (e.g., maximize growth rate or minimize metabolic adjustments and do not make use of flux measurements often available for the wild-type strain. In this work, we introduce the OptForce procedure that identifies all possible engineering interventions by classifying reactions in the metabolic model depending upon whether their flux values must increase, decrease or become equal to zero to meet a pre-specified overproduction target. We hierarchically apply this classification rule for pairs, triples, quadruples, etc. of reactions. This leads to the identification of a sufficient and non-redundant set of fluxes that must change (i.e., MUST set to meet a pre-specified overproduction target. Starting with this set we subsequently extract a minimal set of fluxes that must actively be forced through genetic manipulations (i.e., FORCE set to ensure that all fluxes in the network are consistent with the overproduction objective. We demonstrate our OptForce framework for succinate production in Escherichia coli using the most recent in silico E. coli model, iAF1260. The method not only recapitulates existing engineering strategies but also reveals non-intuitive ones that boost succinate production by performing coordinated changes on pathways distant from the last steps of succinate synthesis.
J.J.M. Pel (Johan); C.W. Spoor (Cornelis); A.L. Pool-Goudzwaard (Annelies); G.A. Hoek van Dijke; C.J. Snijders (Chris)
2008-01-01
textabstractEffective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a validat
Institute of Scientific and Technical Information of China (English)
ZHANG Wei-ling; WANG Ya-jing; GAO Xiu-mei; GAO Xu; PENG Shu-juan; ZHENG Yin; OKEKE Chukwunweike Ikechukwu
2013-01-01
Objective To apply the response surface-central composite design to developing and optimizing the oral fast disintegrating tablets (ODT) formulation for Jiawei Qing'e,a kind of prescription of Chinese herbal medicine.Methods The bitterness of Jiawei Qing'e was masked using Eudragit E-100 by solvent evaporation technique.Response surface approach was applied to investigating the interaction of formulation parameters in optimizing the formulation.The independent variables were Eudragit E-100/drug ratio (X1),amount of disintegrants (X2),and the amount of diluents (X3).The disintegration time (Y1),hardness (Y2),and weight variations of the tablets were characterized.Results The models predicted levels ofX1 =4.63％,X2 =5.25％,and X3 =34.33％,for the optimal formulation having a hardness of 3.0 kg with the disintegration time of 30 s within experimental region.The observed response of Y1 =26.5 s and Y2 =3.14 kg reasonably agreed with the predicted response.Conclusion Response surface methodology shows the good predictability and reliability in optimizing the formulation.The optimized ODT of Jiawei Qing'e has acceptable taste,rapid disintegrating ability,and good mechanical strength.
Directory of Open Access Journals (Sweden)
Gurinder Singh
2012-01-01
Full Text Available Furosemide is a powerful diuretic and antihypertensive drug which has low bioavailability due to hepatic first pass metabolism and has a short half-life of 2 hours. To overcome the above drawback, the present study was carried out to formulate and evaluate sustained release (SR pellets of furosemide for oral administration prepared by extrusion/spheronization. Drug Coat L-100 was used within the pellet core along with microcrystalline cellulose as the diluent and concentration of selected binder was optimized to be 1.2%. The formulation was prepared with drug to polymer ratio 1:3. It was optimized using Design of Experiments by employing a 3 2 central composite design that was used to systematically optimize the process parameters combined with response surface methodology. Dissolution studies were carried out with USP apparatus Type I (basket type in both simulated gastric and intestinal pH. The statistical technique, i.e., the two-tailed paired t test and one-way ANOVA of in vitro data has proposed that there was very significant ( P≤0.05 difference in dissolution profile of furosemide SR pellets when compared with pure drug and commercial product. Validation of the process optimization study indicated an extremely high degree of prognostic ability. The study effectively undertook the development of optimized process parameters of pelletization of furosemide pellets with tremendous SR characteristics.
Singh, Gurinder; Pai, Roopa S; Devi, V Kusum
2012-01-01
Furosemide is a powerful diuretic and antihypertensive drug which has low bioavailability due to hepatic first pass metabolism and has a short half-life of 2 hours. To overcome the above drawback, the present study was carried out to formulate and evaluate sustained release (SR) pellets of furosemide for oral administration prepared by extrusion/spheronization. Drug Coat L-100 was used within the pellet core along with microcrystalline cellulose as the diluent and concentration of selected binder was optimized to be 1.2%. The formulation was prepared with drug to polymer ratio 1:3. It was optimized using Design of Experiments by employing a 3(2) central composite design that was used to systematically optimize the process parameters combined with response surface methodology. Dissolution studies were carried out with USP apparatus Type I (basket type) in both simulated gastric and intestinal pH. The statistical technique, i.e., the two-tailed paired t test and one-way ANOVA of in vitro data has proposed that there was very significant (P≤0.05) difference in dissolution profile of furosemide SR pellets when compared with pure drug and commercial product. Validation of the process optimization study indicated an extremely high degree of prognostic ability. The study effectively undertook the development of optimized process parameters of pelletization of furosemide pellets with tremendous SR characteristics.
Palao, J P; Palao, Jose P.; Kosloff, Ronnie
2002-01-01
A quantum gate is realized by specific unitary transformations operating on states representing qubits. Considering a quantum system employed as an element in a quantum computing scheme, the task is therefore to enforce the pre-specified unitary transformation. This task is carried out by an external time dependent field. Optimal control theory has been suggested as a method to compute the external field which alters the evolution of the system such that it performs the desire unitary transformation. This study compares two recent implementations of optimal control theory to find the field that induces a quantum gate. The first approach is based on the equation of motion of the unitary transformation. The second approach generalizes the state to state formulation of optimal control theory. This work highlight the formal relation between the two approaches.
Optimal Force Control of Vibro-Impact Systems for Autonomous Drilling Applications
Aldrich, Jack B.; Okon, Avi B.
2012-01-01
The need to maintain optimal energy efficiency is critical during the drilling operations performed on future and current planetary rover missions (see figure). Specifically, this innovation seeks to solve the following problem. Given a spring-loaded percussive drill driven by a voice-coil motor, one needs to determine the optimal input voltage waveform (periodic function) and the optimal hammering period that minimizes the dissipated energy, while ensuring that the hammer-to-rock impacts are made with sufficient (user-defined) impact velocity (or impact energy). To solve this problem, it was first observed that when voice-coil-actuated percussive drills are driven at high power, it is of paramount importance to ensure that the electrical current of the device remains in phase with the velocity of the hammer. Otherwise, negative work is performed and the drill experiences a loss of performance (i.e., reduced impact energy) and an increase in Joule heating (i.e., reduction in energy efficiency). This observation has motivated many drilling products to incorporate the standard bang-bang control approach for driving their percussive drills. However, the bang-bang control approach is significantly less efficient than the optimal energy-efficient control approach solved herein. To obtain this solution, the standard tools of classical optimal control theory were applied. It is worth noting that these tools inherently require the solution of a two-point boundary value problem (TPBVP), i.e., a system of differential equations where half the equations have unknown boundary conditions. Typically, the TPBVP is impossible to solve analytically for high-dimensional dynamic systems. However, for the case of the spring-loaded vibro-impactor, this approach yields the exact optimal control solution as the sum of four analytic functions whose coefficients are determined using a simple, easy-to-implement algorithm. Once the optimal control waveform is determined, it can be used
Three-dimensional optimization of staggered finned circular and elliptic tubes in forced convection
Energy Technology Data Exchange (ETDEWEB)
Matos, R.S.; Vargas, J.V.C. [Departamento de Engenharia Mecanica, Centro Politecnico, Universidade Federal do Parana, Caixa Postal 19011, PR 81531-990, Curitiba (Brazil); Laursen, T.A. [Department of Civil and Environmental Engineering, Duke University, 27708-0287, Durham, NC (United States); Bejan, A. [Department of Mechanical Engineering and Materials Science, Duke University, 27708-0300, Durham, NC (United States)
2004-05-01
This paper presents a three-dimensional numerical and experimental geometric optimization study to maximize the total heat transfer rate between a bundle of finned tubes in a given volume and external flow, for staggered arrangements of circular and elliptic tubes. Experimental results were obtained for circular and elliptic configurations with twelve tubes, starting with an equilateral triangle configuration, which fitted uniformly into the fixed volume with a resulting optimal dimensionless tube-to-tube spacing of S/2b = 1.5, where S is the actual spacing and b is the smaller semi-axis of the ellipse. Several experimental configurations were built by reducing the tube-to-tube spacings, identifying the optimal spacing for maximum heat transfer. Similarly, it was possible to investigate the existence of optima with respect to two other geometric degrees of freedom, such as tube eccentricity and fin-to-fin spacing. The results are reported for air as the external fluid in the laminar regime, for Re{sub L} = 852 and 1065, where L is the swept length of the fixed volume. Circular and elliptic arrangements with the same flow obstruction cross-sectional area were compared on the basis of maximizing the total heat transfer. This criterion allows one to isolate and quantify the heat transfer gain, by studying arrangements with equivalent total pressure drops independently of the tube cross-section shape. This paper continues with three-dimensional numerical optimization results for finned circular and elliptic tubes arrangements, which are validated by direct comparison with experimental measurements. Global optima with respect to tube-to-tube spacing, eccentricity and fin-to-fin spacing (S/2b{approx_equal}0.5, e{approx_equal}0.5, {phi}{sub f}{approx_equal}0.06 for Re{sub L}=852 and 1065) were found and reported in dimensionless terms. A relative heat transfer gain of up to 19% is observed in the optimal elliptic arrangement, as compared to the optimal circular one. The
Bogacz, Rafal; Brown, Eric; Moehlis, Jeff; Holmes, Philip; Cohen, Jonathan D.
2006-01-01
In this article, the authors consider optimal decision making in two-alternative forced-choice (TAFC) tasks. They begin by analyzing 6 models of TAFC decision making and show that all but one can be reduced to the drift diffusion model, implementing the statistically optimal algorithm (most accurate for a given speed or fastest for a given…
Almer, Alexander; Schnabel, Thomas; Perko, Roland; Raggam, Johann; Köfler, Armin; Feischl, Richard
2016-04-01
Climate change will lead to a dramatic increase in damage from forest fires in Europe by the end of this century. In the Mediterranean region, the average annual area affected by forest fires has quadrupled since the 1960s (WWF, 2012). The number of forest fires is also on the increase in Central and Northern Europe. The Austrian forest fire database shows a total of 584 fires for the period 2012 to 2014, while even large areas of Sweden were hit by forest fires in August 2014, which were brought under control only after two weeks of intense fire-fighting efforts supported by European civil protection modules. Based on these facts, the improvements in forest fire control are a major international issue in the quest to protect human lives and resources as well as to reduce the negative environmental impact of these fires to a minimum. Within this paper the development of a multi-functional airborne management support system within the frame of the Austrian national safety and security research programme (KIRAS) is described. The main goal of the developments is to assist crisis management tasks of civil emergency teams and armed forces in disaster management by providing multi spectral, near real-time airborne image data products. As time, flexibility and reliability as well as objective information are crucial aspects in emergency management, the used components are tailored to meet these requirements. An airborne multi-functional management support system was developed as part of the national funded project AIRWATCH, which enables real-time monitoring of natural disasters based on optical and thermal images. Airborne image acquisition, a broadband line of sight downlink and near real-time processing solutions allow the generation of an up-to-date geo-referenced situation map. Furthermore, this paper presents ongoing developments for innovative extensions and research activities designed to optimize command operations in national and international fire
The Optimal Force Mix and Allocation of Fires for the Future Field Artillery
1991-09-01
integer solution takes an inordinate amount of central processor time (CPU). Solving the problem as a Relaxed Mixed Integer Problem ( RMIP ), not only...takes a fraction of the CPU time, but also yields a very good real number approXimaton. 42 The Test Case problem was first solved using RMIP and then...R)))) * -- SOLVE MODEL USING RELAXED MIP-_ __ MODEL ARTYATTACK / ALL / SOLVE ARTYATTACK USING RMIP MINIMIZING TOTCOST; *-GENERATE INTEGER SOLUTION BY
Noble, Marlene A.; Rosenberger, Kurt; Robertson, George L.
2015-01-01
Contrary to many previous reports, winds do drive currents along the shelf in the central portion of the Southern California Bight (SCB). Winds off Huntington Beach CA are the dominant forcing for currents over the nearshore region of the shelf (water depths less than 20 m). Winds control about 50–70% of the energy in nearshore alongshelf surface currents. The wind-driven current amplitudes are also anomalously high. For a relatively weak 1 dyne/cm2 wind stress, the alongshelf surface current amplitudes in this region can reach 80 cm/s or more. Mid-depth current amplitudes for the same wind stress are around 30–40 cm/s. These wind-driven surface current amplitudes are much larger than previously measured over other nearshore shelf regions, perhaps because this program is one of the few that measured currents within a meter of the surface. The near-bed cross-shelf currents over the nearshore region of the Huntington Beach shelf have an Ekman response to winds in that they upwell (downwell) for down (up) coast winds. This response disappears further offshore. Hence, there is upwelling in the SCB, but it does not occur across the entire shelf. Subthermocline water in the nearshore region that may contain nutrients and plankton move onshore when winds are southeastward, but subthermocline water over the shelf break is not transported to the beach. The currents over the outer shelf are not predominately controlled by winds, consistent with previous reports. Instead, they are mainly driven by cross-shelf pressure gradients that are independent of local wind stress.
Kiri, Lauren; Boyd, Daniel
2015-06-01
Adjusting powder-liquid ratio (P/L) and polyacrylic acid concentration (AC) has been documented as a means of tailoring the handling and mechanical properties of glass ionomer cements (GICs). This work implemented a novel approach in which the interactive effects of these two factors on three key GIC properties (working time, setting time, and compressive strength) were investigated using a central composite design of experiments. Using nonlinear regression analysis, formulation-property relationships were derived for each property, which enabled prediction of an optimal formulation (P/L and AC) through application of the desirability approach. A novel aluminum free GIC was investigated, as this material may present the first clinically viable GIC for use in injectable spinal applications, such as vertebroplasty. Ultimately, this study presents the first series of predictive regression models that explain the formulation-dependence of a GIC, and the first statistical method for optimizing both P/L and AC depending on user-defined inputs.
Directory of Open Access Journals (Sweden)
Skokanová Hana
2016-03-01
Full Text Available The article compares and points out differences in driving forces of four main landscape change processes that shaped post-socialist countries and old democratic countries of Central Europe during the last two centuries. Studying landscape change processes and corresponding driving forces helps in understanding patterns of present landscape and can help among others in better prediction of future landscape change trends. Here, the presented results are based on review of scientific articles published in peer-reviewed journals between 2000 and 2014. Driving forces affecting these processes were grouped into four categories. Economic forces drove mainly agricultural intensification; agricultural land abandonment and urbanisation and were pronounced especially in the second half of the 20th century and at the beginning of the 21st century. Technological driving forces affected agricultural intensification especially in the 19th century and the second half of the 20th century while cultural driving forces had the biggest impact on urbanisation at the beginning of the 21st century. Political driving forces affected agricultural intensification, urbanisation as well as agricultural land abandonment and were pronounced mainly during the second half of the 20th century in the post-socialist countries. Political forces in the form of subsidies drove agricultural extensification at the beginning of the 21st century. The drivers for the agricultural intensification as well as urbanisation seem to be similar for both old democratic and post-socialist countries. In contrast, agricultural land abandonment in the old democratic countries was driven by technological, cultural and economic driving forces while in the post-socialist countries the political driving forces were mainly responsible. Changes in systems for subsidies and changes in the agricultural commodity markets are also responsible for different frequencies and rates of extensification of
Optimal Power Consumption in a Central Heating System with Geothermal Heat Pump
DEFF Research Database (Denmark)
Tahersima, Fatemeh; Stoustrup, Jakob; Rasmussen, Henrik
2011-01-01
, lowering the temperature of forward water alleviates energy consumption. The hypothesis is that the minimum water temperature is achieved when at least one of the hydronic heaters in the building works at full capacity. The setpoint of the forward water temperature is found by solving a model based...... optimization problem in a receding finite horizon. The optimization objective is to maintain the local control signal of the largest thermal load near full capacity. The overall control system hierarchy is composed of local PI controllers for each subsystem and an MPC controller which orchestrates the PI...
Parhusip, H. A.; Trihandaru, S.; Susanto, B.; Prasetyo, S. Y. J.; Agus, Y. H.; Simanjuntak, B. H.
2017-03-01
Several algorithms and objective functions on paddy crops have been studied to get optimal paddy crops in Central Java based on the data given from Surakarta and Boyolali. The algorithms are linear solver, least square and Ant Colony Algorithms (ACO) to develop optimization procedures on paddy crops modelled with Modified GSTAR (Generalized Space-Time Autoregressive) and nonlinear models where the nonlinear models are quadratic and power functions. The studied data contain paddy crops from Surakarta and Boyolali determining the best period of planting in the year 1992-2012 for Surakarta where 3 periods for planting are known and the optimal amount of paddy crops in Boyolali in the year 2008-2013. Having these analyses may guide the local agriculture government to give a decision on rice sustainability in its region. The best period for planting in Surakarta is observed, i.e. the best period is in September-December based on the data 1992-2012 by considering the planting area, the cropping area, and the paddy crops are the most important factors to be taken into account. As a result, we can refer the paddy crops in this best period (about 60.4 thousand tons per year) as the optimal results in 1992-2012 where the used objective function is quadratic. According to the research, the optimal paddy crops in Boyolali about 280 thousand tons per year where the studied factors are the amount of rainfalls, the harvested area and the paddy crops in 2008-2013. In this case, linear and power functions are studied to be the objective functions. Compared to all studied algorithms, the linear solver is still recommended to be an optimization tool for a local agriculture government to predict paddy crops in future.
Directory of Open Access Journals (Sweden)
Young-Dae Hong
2016-02-01
Full Text Available This paper proposes a method to produce the stable walking of humanoid robots by incorporating the vertical center of mass (COM and foot motions, which are generated by the evolutionary optimized central pattern generator (CPG, into the modifiable walking pattern generator (MWPG. The MWPG extends the conventional 3-D linear inverted pendulum model (3-D LIPM by allowing a zero moment point (ZMP variation. The disturbance caused by the vertical COM motion is compensated in real time by the sensory feedback in the CPG. In this paper, the vertical foot trajectory of the swinging leg, as well as the vertical COM trajectory of the 3-D LIPM, are generated by the CPG for the effective compensation of the disturbance. Consequently, using the proposed method, the humanoid robot is able to walk with a vertical COM and the foot motions generated by the CPG, while modifying its walking patterns by using the MWPG in real time. The CPG with the sensory feedback is optimized to obtain the desired output signals. The optimization of the CPG is formulated as a constrained optimization problem with equality constraints and is solved by two-phase evolutionary programming (TPEP. The validity of the proposed method is verified through walking experiments for the small-sized humanoid robot, HanSaRam-IX (HSR-IX.
Optimized Model Surfaces for Advanced Atomic Force Microscopy Studies of Surface Nanobubbles.
Song, Bo; Zhou, Yi; Schönherr, Holger
2016-11-01
The formation of self-assembled monolayers (SAMs) of binary mixtures of 16-mercaptohexadecanoic acid (MHDA) and 1-octadecanethiol (ODT) on ultraflat template-stripped gold (TSG) surfaces was systematically investigated to clarify the assembly behavior, composition, and degree of possible phase segregation in light of atomic force microscopy (AFM) studies of surface nanobubbles on these substrates. The data for SAMs on TSG were compared to those obtained by adsorption on rough evaporated gold, as reported in a previous study. Quartz crystal microbalance and surface plasmon resonance data acquired in situ on TSG indicate that similar to SAM formation on conventional evaporated gold substrates ODT and MHDA form monolayers and bilayers, respectively. The second layer on MHDA, whose formation is attributed to hydrogen bonding, can be easily removed by adequate rinsing with water. The favorable agreement of the grazing incidence reflection Fourier transform infrared (GIR FTIR) spectroscopy and contact angle data analyzed with the Israelachvili-Gee model suggests that the binary SAMs do not segregate laterally. This conclusion is fully validated by high-resolution friction force AFM observations down to a length scale of 8-10 nm, which is much smaller than the typical observed surface nanobubble radii. Finally, correspondingly functionalized TSG substrates are shown to be valuable supports for studying surface nanobubbles by AFM in water and for addressing the relation between surface functionality and nanobubble formation and properties.
Energy Technology Data Exchange (ETDEWEB)
Gutierrez Ramirez, Ranulfo; Fernandez Montiel, Manuel Francisco [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)
1999-07-01
Some recent experiences of the Management of Thermal Processes of the Instituto de Investigaciones Electricas (IIE) related to the works on generating power stations of electricity, plants of cogeneration and energy saving are presented. [Spanish] Se presentan algunas experiencias recientes de la Gerencia de Procesos Termicos del Instituto de Investigaciones Electricas (IIE) relacionadas con los trabajos sobre centrales generadoras de electricidad, plantas de cogeneracion y ahorro de energia.
Directory of Open Access Journals (Sweden)
Azami Mahsa
2012-01-01
Full Text Available In this study the degradation of Methyl Orange, using Fenton reaction was studied and optimized using central composite design as a response surface methodology. The effects of various experimental parameters in this reaction were investigated using central composite design. 28 experiments, with 4 factors and 5 levels for each factor were designed. These factors (or variables were: initial concentration of Fe (II, initial concentration of H2O2, initial concentration of oxalate and the reaction time. A full-quadratic polynomial equation between the percentage of dye degradation (as a response and the studied parameters was established. After removing the non-significant variables from the model, response surface method was used to obtain the optimum conditions. The optimum ranges of variables were: 0.25 - 0.35 mM for initial concentration of Fe (II, 5-17 mM for initial concentration of H2O2, 4-9 mM for initial concentration of oxalate, and 50-80 min for the reaction time. Also the results of extra experiments showed that these optimized values can be used for real samples and yield to a high value for the response.
Feedback Optimal Control of Low-thrust Orbit Transfer in Central Gravity Field
Directory of Open Access Journals (Sweden)
Ashraf H. Owis
2013-05-01
Full Text Available Low-thrust trajectories with variable radial thrust is studied in this paper. The problem is tackled by solving the Hamilton- Jacobi-Bellman equation via State Dependent Riccati Equation( STDE technique devised for nonlinear systems. Instead of solving the two-point boundary value problem in which the classical optimal control is stated, this technique allows us to derive closed-loop solutions. The idea of the work consists in factorizing the original nonlinear dynamical system into a quasi-linear state dependent system of ordinary differential equations. The generating function technique is then applied to this new dynamical system, the feedback optimal control is solved. We circumvent in this way the problem of expanding the vector field and truncating higher-order terms because no remainders are lost in the undertaken approach. This technique can be applied to any planet-to-planet transfer; it has been applied here to the Earth-Mars low-thrust transfer
IL-21 optimizes T cell and humoral responses in the central nervous system during viral encephalitis
Phares, Timothy W.; DiSano, Krista D.; Hinton, David R.; Hwang, Mihyun; Zajac, Allan J.; Stohlman, Stephen A.; Bergmann, Cornelia C.
2013-01-01
Acute coronavirus encephalomyelitis is controlled by T cells while humoral responses suppress virus persistence. This study defines the contribution of interleukin (IL)-21, a regulator of T and B cell function, to central nervous system (CNS) immunity. IL-21 receptor deficiency did not affect peripheral T cell activation or trafficking, but dampened granzyme B, gamma interferon and IL-10 expression by CNS T cells and reduced serum and intrathecal humoral responses. Viral control was already lost prior to humoral CNS responses, but demyelination remained comparable. These data demonstrate a critical role of IL-21 in regulating CNS immunity, sustaining viral persistence and preventing mortality. PMID:23992866
Moissenet, Florent; Chèze, Laurence; Dumas, Raphaël
2012-06-01
Inverse dynamics combined with a constrained static optimization analysis has often been proposed to solve the muscular redundancy problem. Typically, the optimization problem consists in a cost function to be minimized and some equality and inequality constraints to be fulfilled. Penalty-based and Lagrange multipliers methods are common optimization methods for the equality constraints management. More recently, the pseudo-inverse method has been introduced in the field of biomechanics. The purpose of this paper is to evaluate the ability and the efficiency of this new method to solve the muscular redundancy problem, by comparing respectively the musculo-tendon forces prediction and its cost-effectiveness against common optimization methods. Since algorithm efficiency and equality constraints fulfillment highly belong to the optimization method, a two-phase procedure is proposed in order to identify and compare the complexity of the cost function, the number of iterations needed to find a solution and the computational time of the penalty-based method, the Lagrange multipliers method and pseudo-inverse method. Using a 2D knee musculo-skeletal model in an isometric context, the study of the cost functions isovalue curves shows that the solution space is 2D with the penalty-based method, 3D with the Lagrange multipliers method and 1D with the pseudo-inverse method. The minimal cost function area (defined as the area corresponding to 5% over the minimal cost) obtained for the pseudo-inverse method is very limited and along the solution space line, whereas the minimal cost function area obtained for other methods are larger or more complex. Moreover, when using a 3D lower limb musculo-skeletal model during a gait cycle simulation, the pseudo-inverse method provides the lowest number of iterations while Lagrange multipliers and pseudo-inverse method have almost the same computational time. The pseudo-inverse method, by providing a better suited cost function and an
Institute of Scientific and Technical Information of China (English)
WANG Yunfeng; BIAN Jinian; HONG Xianlong; ZHOU Qiang; WU Qiang
2007-01-01
As the feature size of integrated circuits is reduced to the deep sub-micron level or the nanometer level, the interconnect delay is becoming more and more important in determining the total delay of a circuit. Re-synthesis after floorptan is expected to be very helpful for reducing the interconnect delay of a circuit. In this paper,a force-balance-based re-synthesis algorithm for interconnect delay o ptimization after floorplan is proposed. The algorithm optimizes the inter connect delay by changing the operation scheduling and the functional unit allocation andbinding. With this method the number and positions of all functional units are not changed, but some operations are allocated or bound to different units. Preliminary experimental results show that the interconnect wire delays are reduced efficiently without destroying the floorplan performance.
Directory of Open Access Journals (Sweden)
Sümeyra Cevheroğlu Çıra
2016-01-01
Full Text Available Factors affecting the final surface quality of polished marble are not yet fully understood. Clarifying these factors for optimization of multivariate polishing process by trial and error method is difficult, time-consuming, and costly task. In this study, the empirical practices were carried out using an experimental design, specifically, a central composite inscribed (CCI design. The factors considered in CCI design were belt speed, rotational speed, and pressure of the polishing head, and the responses were surface glossiness and roughness. Mathematical models describing responses were produced using experimental datasets, and analysis of variance (ANOVA was used to assess the fit of the models generated with the experimental data. For process optimization, desirability function analysis (DFA was used. This study has shown that the CCI could efficiently be applied for the modelling of polishing machine for surface quality of marble strips. Better surface quality generally resulted from lower belt speeds, which increased contact time between the abrasives and strips. Optimized surface quality for marble specimen was established.
Directory of Open Access Journals (Sweden)
Shu Guowei
2016-06-01
Full Text Available The objective of the present study was to obtain the optimum proportion of the carbon source and prebiotics for Bifidobacterium bifidum BB01 by the central composite design (CCD. The effect of carbon source (lactose and two prebiotics (inulin and fructooligosaccharides on the BB01 were observed by measuring the OD600 value, pH value and the viable counts at 18h. The final optimized concentrations of carbon source and prebiotics were: lactose 1.6%, inulin 0.26%, and fructooligosaccharides 0.22%. The result indicates that the growth of B. bifidum BB01 shows an significant increase in the optimized culture medium (p < 0.05, the OD600 value reached 1.434 at 18h, which increased 6.58% compared to the control. And the viable counts of B. bifidum BB01 increased 24.36% and reached (2.17±0.06 ×109cfu/mL. The results show that the optimization of the carbon source and prebiotics using CCD in this study is workable and necessary.
Directory of Open Access Journals (Sweden)
Abd Elaziz Sarrai
2016-05-01
Full Text Available The feasibility of the application of the Photo-Fenton process in the treatment of aqueous solution contaminated by Tylosin antibiotic was evaluated. The Response Surface Methodology (RSM based on Central Composite Design (CCD was used to evaluate and optimize the effect of hydrogen peroxide, ferrous ion concentration and initial pH as independent variables on the total organic carbon (TOC removal as the response function. The interaction effects and optimal parameters were obtained by using MODDE software. The significance of the independent variables and their interactions was tested by means of analysis of variance (ANOVA with a 95% confidence level. Results show that the concentration of the ferrous ion and pH were the main parameters affecting TOC removal, while peroxide concentration had a slight effect on the reaction. The optimum operating conditions to achieve maximum TOC removal were determined. The model prediction for maximum TOC removal was compared to the experimental result at optimal operating conditions. A good agreement between the model prediction and experimental results confirms the soundness of the developed model.
Institute of Scientific and Technical Information of China (English)
Shu-fang WANG; Hai-yan FANG; Hai-bin QU
2011-01-01
Central composite design (CCD), together with multiple linear regression, was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography (MEKC) for the determination of albiflorin, paeoniflorin, liquiritin, and glycyrrhizic acid in the traditional Chinese medicine (TCM) prescription,Yangwei granule. Concentrations of sodium deoxycholate (SDC) and borate, and proportions of ammonia, acetonitrile,and methanol were optimized. The total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation efficiency. The optimum electrophoretic buffer contained 80 mmol/L SDC, 20 mmol/L borate, 5% (v/v) methanol, 0.5% (v/v) ammonia, and 5% (v/v) acetonitrile. The correlation coefficients (R2) between the peak areas and the corresponding concentrations of analytes were greater than 0.9956. The limits of detection (LODs) (S/N=3) of the analytes were 0.97-4.00 μg/mi. The results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.
Blaya, Miceli Beck Guimaraes; Westphalen, Graziela Henriques; Guimaraes, Magali Beck; Hirakata, Luciana Mayumi
2009-01-01
The aim of this study was to analyze the mechanical behavior of different orthodontic retraction loops. Two designs of orthodontic loops for closing space were analyzed: teardrop-shaped (T) and circle-shaped loop (C), of two different heights (6 and 8 mm), and two types of orthodontic wires (stainless steel - 0.19' x 0.25'; TMA - titanium molybdenum alloy - 0.016' x 0.016'). The sample consisted of 80 loops, divided into 8 groups determined by the combination shape/height/type of wire, which were submitted to tensile testing at a speed of 2 mm/min., to measure the quantity of force generated when activated in the interval of 0.75 mm and 2.25 mm. The results were submitted to the ANOVA and Tukey statistical tests to compare the groups, and the Student's-t test to compare the means of two groups. Statistically higher values were observed for the size 6 mm, circle shape and stainless steel composition. The group "teardrop-8 mm-TMA" together with the group "circle-8 mm-TMA" presented the lowest mean value, differing statistically from all of the other groups. It was concluded that the alloy of the wire and the height of the loop would be more important than the loop design.
Bartolomei, Massimiliano; Carmona-Novillo, Estela; Hernández, Marta I; Campos-Martínez, José; Pirani, Fernando; Giorgi, Giacomo; Yamashita, Koichi
2014-02-20
Graphynes are novel two-dimensional carbon-based materials that have been proposed as molecular filters, especially for water purification technologies. We carry out first-principles electronic structure calculations at the MP2C level of theory to assess the interaction between water and graphyne, graphdiyne, and graphtriyne pores. The computed penetration barriers suggest that water transport is unfeasible through graphyne while being unimpeded for graphtriyne. For graphdiyne, with a pore size almost matching that of water, a low barrier is found that in turn disappears if an active hydrogen bond with an additional water molecule on the opposite side of the opening is considered. Thus, in contrast with previous determinations, our results do not exclude graphdiyne as a promising membrane for water filtration. In fact, present calculations lead to water permeation probabilities that are 2 orders of magnitude larger than estimations based on common force fields. A new pair potential for the water-carbon noncovalent component of the interaction is proposed for molecular dynamics simulations involving graphdiyne and water.
Cosseddu, Salvatore; Infante, Ivan
2017-01-10
In a typical colloidal CdSe nanocrystal more than 50% of the atoms are located at the surface. These atoms can give rise to electronic traps that can deteriorate the performance of optoelectronic devices made of these nanomaterials. A key challenge in this field is thus to understand with atomistic detail the chemical processes occurring at the nanocrystal surface. Molecular dynamics simulations represent an important tool to unveil these processes, but its implementation is strongly limited by the difficulties of finely tuning classical force fields parameters, primarily caused by the unavailability of experimental data of these materials that are suitable in the parametrization procedures. In this work, we present a general scheme to produce force field parameters from first-principles calculations. This approach is based on a newly developed stochastic optimization algorithm called Adaptive Rate Monte Carlo, which is designed to be robust, accurate, easy-to-use, and flexible enough to be straightforwardly extended to other nanomaterials. We demonstrate that our algorithm provides a set of parameters capable of satisfactorily describing nonstoichiometric CdSe nanocrystals passivated with oleate ligands akin to experimental conditions. We also demonstrate that our new parameters are robust enough to be transferable among crystal structures and nanocrystals of increasing sizes up to the bulk.
2012-04-01
PHONE TYPIST’S SUSPENSE DATE INITIALS Beckwith, GS -11 90 CES/CEAN 773-3667 rs SUBJECT DATE Final Environmental Assessment, Gate 5 (Central Avenue... Kirk Schaumman Air Quality Manager F. E. Warren AFB WY 82005 10 Final Environmental Assessment for Gate 5 (Central Avenue) Interchange Improvements
Thermoeconomic optimization of a Kalina cycle for a central receiver concentrating solar power plant
DEFF Research Database (Denmark)
Modi, Anish; Kærn, Martin Ryhl; Andreasen, Jesper Graa
2016-01-01
Concentrating solar power plants use a number of reflecting mirrors to focus and convert the incident solar energy to heat, and a power cycle to convert this heat into electricity. This paper evaluates the use of a high temperature Kalina cycle for a central receiver concentrating solar power plant...... and the economic perspectives, the results suggest that it is not beneficial to use the Kalina cycle for high temperature concentrating solar power plants....... with direct vapour generation and without storage. The use of the ammonia-water mixture as the power cycle working fluid with non-isothermal evaporation and condensation presents the potential to improve the overall performance of the plant. This however comes at a price of requiring larger heat exchangers...
Directory of Open Access Journals (Sweden)
Deep Mukherjee
2015-06-01
Full Text Available Anaerobic digestion technology is available for converting livestock waste to bio-energy, but its potential is far from fully exploited in the United States because the technology has a scale effect. Utilization of the centralized anaerobic digester (CAD concept could make the technology economically feasible for smaller dairy farms. An interdisciplinary methodology to determine the cost minimizing location, size, and number of CAD facilities in a rural dairy region with mostly small farms is described. This study employs land suitability analysis, operations research model and Geographical Information System (GIS tools to evaluate the environmental, social, and economic constraints in selecting appropriate sites for CADs in Windham County, Connecticut. Results indicate that overall costs are lower if the CADs are of larger size and are smaller in number.
Fyta, Maria; Netz, Roland R
2012-03-28
Using molecular dynamics (MD) simulations in conjunction with the SPC/E water model, we optimize ionic force-field parameters for seven different halide and alkali ions, considering a total of eight ion-pairs. Our strategy is based on simultaneous optimizing single-ion and ion-pair properties, i.e., we first fix ion-water parameters based on single-ion solvation free energies, and in a second step determine the cation-anion interaction parameters (traditionally given by mixing or combination rules) based on the Kirkwood-Buff theory without modification of the ion-water interaction parameters. In doing so, we have introduced scaling factors for the cation-anion Lennard-Jones (LJ) interaction that quantify deviations from the standard mixing rules. For the rather size-symmetric salt solutions involving bromide and chloride ions, the standard mixing rules work fine. On the other hand, for the iodide and fluoride solutions, corresponding to the largest and smallest anion considered in this work, a rescaling of the mixing rules was necessary. For iodide, the experimental activities suggest more tightly bound ion pairing than given by the standard mixing rules, which is achieved in simulations by reducing the scaling factor of the cation-anion LJ energy. For fluoride, the situation is different and the simulations show too large attraction between fluoride and cations when compared with experimental data. For NaF, the situation can be rectified by increasing the cation-anion LJ energy. For KF, it proves necessary to increase the effective cation-anion Lennard-Jones diameter. The optimization strategy outlined in this work can be easily adapted to different kinds of ions.
Institute of Scientific and Technical Information of China (English)
韩江义; 游有鹏; 虞启凯
2012-01-01
After the force transmission performance of mecha-nism was studied, the concept of force transmission capacity was proposed. A multi-objective optimization function consisted of work-space, kinematics performance and force transmission performance was established and applied in optimization design of a three DOF hand controller mechanism. The optimization results of workspace, Jacobian condition number and performance of force transmission of mechanism were analyzed, parameters of primary structure and drive was determined, the prototype was manufactured eventually. The progress of optimization and development has provided references for development of hand controller with outstanding performance.%对机构力传递性能进行研究,并提出力传递能力概念.建立一种综合机构工作空间、运动学性能和力传递性能的多目标优化函数,并应用于一种三平动自由度的手控器机构优化设计.对机构优化结果进行工作空间、机构雅可比条件数和力传递性能分析,确定基本结构参数和动力驱动参数,进一步完成样机制作.优化和研制过程为高性能手控器的研制提供了参考.
Directory of Open Access Journals (Sweden)
Nitu Antonie Renata
2008-04-01
Full Text Available The business strategy of multinational enterprises (MNEs from the automobile industry implanted in Central-Eastern European (CEE countries (Poland, Czech Republic and Romania is an offensive one, global from operational perspective. Mainly it aims the extension of market share through horizontal growth, generally external type single-domain (Mergers and Acquisitions and internal type (Greenfield investments in a lower degree. These enterprises put in practice also a defending strategy for the owned market shares through increasing the efficiency of the production network at global level. This paper aims to present the less evident aspects of tax optimization of the applied business strategy by implemented MNEs in the automobile industry in CEE, and in this context, the necessity to establish transfer prices in accordance with the OECD recommendations, as an obligation assessed by the tax legislations of the considered countries, but also from the necessity of efficient run of these enterprises.
Izadiyan, Parisa; Hemmateenejad, Bahram
2016-01-01
The present study reports on the extraction of antioxidant compounds from Iranian Ocimum basilicum. Central composite design (CCD) was used to investigate the effect of extraction variables on the ultrasound-assisted extraction (UAE). Three independent variables including temperature, methanol to water ratio percent, and sonication time were studied for simultaneous optimization of antioxidant capacity, total phenolic content and extraction yield. Both quantitative modeling and response surface methodology suggested that methanol to water ratio percent and extraction temperature were the most effective parameters of UAE process. However, sonication time was found out to be an insignificant factor in ultrasound-assisted extraction of antioxidant and total phenolic compounds of O. basilicum. The optimum conditions were determined as temperature of 59 °C, methanol to water ratio of 65.2% (v/v), and extraction time of 20 min.
Routray, Sunita; Swain, Ranjita; Rao, Raghupatruni Bhima
2017-04-01
The present study is aimed at investigating the optimization of a mineral separator for processing of beach sand minerals of Bay of Bengal along Ganjam-Rushikulya coast. The central composite design matrix and response surface methodology were applied in designing the experiments to evaluate the interactive effects of the three most important operating variables, such as feed quantity, wash water rate and Shake amplitude of the deck. The predicted values were found to be in good agreement with the experimental values (R2 = 0.97 for grade and 0.98 for recovery). To understand the impact of each variable, three dimensional (3D) plots were also developed for the estimated responses.
A comparison of central composite design and Taguchi method for optimizing Fenton process.
Asghar, Anam; Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan
2014-01-01
In the present study, a comparison of central composite design (CCD) and Taguchi method was established for Fenton oxidation. [Dye]ini, Dye:Fe(+2), H2O2:Fe(+2), and pH were identified control variables while COD and decolorization efficiency were selected responses. L 9 orthogonal array and face-centered CCD were used for the experimental design. Maximum 99% decolorization and 80% COD removal efficiency were obtained under optimum conditions. R squared values of 0.97 and 0.95 for CCD and Taguchi method, respectively, indicate that both models are statistically significant and are in well agreement with each other. Furthermore, Prob > F less than 0.0500 and ANOVA results indicate the good fitting of selected model with experimental results. Nevertheless, possibility of ranking of input variables in terms of percent contribution to the response value has made Taguchi method a suitable approach for scrutinizing the operating parameters. For present case, pH with percent contribution of 87.62% and 66.2% was ranked as the most contributing and significant factor. This finding of Taguchi method was also verified by 3D contour plots of CCD. Therefore, from this comparative study, it is concluded that Taguchi method with 9 experimental runs and simple interaction plots is a suitable alternative to CCD for several chemical engineering applications.
A Comparison of Central Composite Design and Taguchi Method for Optimizing Fenton Process
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Anam Asghar
2014-01-01
Full Text Available In the present study, a comparison of central composite design (CCD and Taguchi method was established for Fenton oxidation. Dyeini, Dye : Fe+2, H2O2 : Fe+2, and pH were identified control variables while COD and decolorization efficiency were selected responses. L9 orthogonal array and face-centered CCD were used for the experimental design. Maximum 99% decolorization and 80% COD removal efficiency were obtained under optimum conditions. R squared values of 0.97 and 0.95 for CCD and Taguchi method, respectively, indicate that both models are statistically significant and are in well agreement with each other. Furthermore, Prob > F less than 0.0500 and ANOVA results indicate the good fitting of selected model with experimental results. Nevertheless, possibility of ranking of input variables in terms of percent contribution to the response value has made Taguchi method a suitable approach for scrutinizing the operating parameters. For present case, pH with percent contribution of 87.62% and 66.2% was ranked as the most contributing and significant factor. This finding of Taguchi method was also verified by 3D contour plots of CCD. Therefore, from this comparative study, it is concluded that Taguchi method with 9 experimental runs and simple interaction plots is a suitable alternative to CCD for several chemical engineering applications.
Escamilla-Cejudo, José Antonio; Báez, Jorge Lara; Peña, Rodolfo; Luna, Patricia Lorena Ruiz; Ordunez, Pedro
2016-11-01
Several Central American countries are seeing continued growth in the number of deaths from chronic kidney disease of nontraditional causes (CKDnT) among farm workers and there is underreporting. This report presents the results of a consensus process coordinated by the Pan American Health Organization/World Health Organization (PAHO/WHO), the United States Centers for Disease Control and Prevention (CDC), and the Latin American Society of Nephrology and Hypertension (SLANH). This consensus seeks to increase the probability of detecting and recording deaths from these causes. There has been recognition of the negative impact of the lack of a standardized instrument and the lack of training in the medical profession for adequate registration of the cause or causes of death. As a result of the consensus, the following has been proposed: temporarily use a code from the Codes for Special Purposes in the International Classification of Diseases (ICD-10); continue to promote use of the WHO international standardized instrument for recording causes and preceding events related to death; increase training of physicians responsible for filling out death certificates; take action to increase the coverage and quality of information on mortality; and create a decision tree to facilitate selection of CKDnT as a specific cause of death, while presenting the role that different regional and subregional mechanisms in the Region of the Americas should play in order to improve CKD and CKDnT mortality records.
Huete-Ortega, María; Calvo-Díaz, Alejandra; Graña, Rocío; Mouriño-Carballido, Beatriz; Marañón, Emilio
2011-11-01
To ascertain the response of phytoplankton size classes to changes in environmental forcing, we determined size-fractionated biomass, carbon fixation and growth (production/biomass) rates in surface waters along the central Atlantic Ocean (26°N-5°S). As a result of the enhanced input of nutrients into the euphotic layer and the higher water column stability found at the equatorial upwelling, we observed increases not only in phytoplankton biomass and primary production, but also in turnover rates, suggesting nutrient limitation of phytoplankton physiology in the oligotrophic central Atlantic. The phytoplankton groups analysed (pico-, small nano-, large nano- and micro-phytoplankton) showed different responses to the equatorial environmental forcing, in terms of carbon biomass, primary production and growth rate. Large nano- and micro-phytoplankton consistently showed higher growth rates and carbon fixation to chl a ratios than smaller phytoplankton. We observed a higher stimulating effect of increased nitrate supply on the small phytoplankton growth rates. This observation can be explained by the dynamics of the equatorial upwelling, where the continuous but small nutrient input into the euphotic layer provide a competitive advantage for smaller cells adapted to oligotrophic conditions. The size-fractionated approach shown here reveals important group-specific differences in the response to environmental forcing, which cannot be appreciated in bulk measurements of the whole community.
Omanovic-Miklicanin, Enisa; Valzacchi, Sandro; Simoneau, Catherine; Gilliland, Douglas; Rossi, Francois
2014-10-01
A complete characterization of the different physico-chemical properties of nanoparticles (NPs) is necessary for the evaluation of their impact on health and environment. Among these properties, the surface characterization of the nanomaterial is the least developed and in many cases limited to the measurement of surface composition and zetapotential. The biological surface adsorption index approach (BSAI) for characterization of surface adsorption properties of NPs has recently been introduced (Xia et al. Nat Nanotechnol 5:671-675, 2010; Xia et al. ACS Nano 5(11):9074-9081, 2011). The BSAI approach offers in principle the possibility to characterize the different interaction forces exerted between a NP's surface and an organic--and by extension biological--entity. The present work further develops the BSAI approach and optimizes a solid-phase microextraction gas chromatography-mass spectrometry (SPME/GC-MS) method which, as an outcome, gives a better-defined quantification of the adsorption properties on NPs. We investigated the various aspects of the SPME/GC-MS method, including kinetics of adsorption of probe compounds on SPME fiber, kinetic of adsorption of probe compounds on NP's surface, and optimization of NP's concentration. The optimized conditions were then tested on 33 probe compounds and on Au NPs (15 nm) and SiO2 NPs (50 nm). The procedure allowed the identification of three compounds adsorbed by silica NPs and nine compounds by Au NPs, with equilibrium times which varied between 30 min and 12 h. Adsorption coefficients of 4.66 ± 0.23 and 4.44 ± 0.26 were calculated for 1-methylnaphtalene and biphenyl, compared to literature values of 4.89 and 5.18, respectively. The results demonstrated that the detailed optimization of the SPME/GC-MS method under various conditions is a critical factor and a prerequisite to the application of the BSAI approach as a tool to characterize surface adsorption properties of NPs and therefore to draw any further
Lim, Jun-Wei; Beh, Hoe-Guan; Ching, Dennis Ling Chuan; Ho, Yeek-Chia; Baloo, Lavania; Bashir, Mohammed J. K.; Wee, Seng-Kew
2016-12-01
The present study provides an insight into the optimization of a glucose and sucrose mixture to enhance the denitrification process. Central Composite Design was applied to design the batch experiments with the factors of glucose and sucrose measured as carbon-to-nitrogen (C:N) ratio each and the response of percentage removal of nitrate-nitrogen (NO3 --N). Results showed that the polynomial regression model of NO3 --N removal had been successfully derived, capable of describing the interactive relationships of glucose and sucrose mixture that influenced the denitrification process. Furthermore, the presence of glucose was noticed to have more consequential effect on NO3 --N removal as opposed to sucrose. The optimum carbon sources mixture to achieve complete removal of NO3 --N required lesser glucose (C:N ratio of 1.0:1.0) than sucrose (C:N ratio of 2.4:1.0). At the optimum glucose and sucrose mixture, the activated sludge showed faster acclimation towards glucose used to perform the denitrification process. Later upon the acclimation with sucrose, the glucose uptake rate by the activated sludge abated. Therefore, it is vital to optimize the added carbon sources mixture to ensure the rapid and complete removal of NO3 --N via the denitrification process.
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Le Pham Tan Quoc
2013-12-01
Full Text Available The aim of this study was the investigation on main factors (the grind time, ratio of water/peel and distillation time affecting the amount of essential oil after distilling. Researching and optimizing the factors for essential oil production by laboratory – scale distillation and the yield was evaluated using the Response Surface Methodology (RSM with Central Composite Face Centered (CCF model. There is the interaction between ratio of water/peel, distillation time and grind time with volume of essential oil extracted. Optimal result which is essential oil was 1.83 ml (y with quantity of kumquat peel/batch of 50 g, grind time (x1 in 118 seconds, ratio of water/peel (x2 was 6/1, distillation time (x3 during 32 minutes at 100 oC. The essential oil from the peel of C.microcarpa (Hassk. Bunge was analysed by GC-MS method. In which, there are a lot of compounds were useful, it can use widely in the food processing and the cosmetics industry, for instance limonene, α-Pinene, β-Pinene, β-Myrcene, Sabinen.
Gu, Bing; Linehan, Brian; Tseng, Yin-Chao
2015-08-01
A central composite design approach was applied to study the effect of polymer concentration, inlet temperature and air flow rate on the spray drying process of the Büchi B-90 nano spray dryer (B-90). Hypromellose acetate succinate-LF was used for the Design of Experiment (DoE) study. Statistically significant models to predict the yield, spray rate, and drying efficiency were generated from the study. The spray drying conditions were optimized according to the models to maximize the yield and efficiency of the process. The models were further validated using a poorly water-soluble investigational compound (BI064) from Boehringer Ingelheim Pharmaceuticals. The polymer/drug ratio ranged from 1/1 to 3/1w/w. The spray dried formulations were amorphous determined by differential scanning calorimetry and X-ray powder diffraction. The particle size of the spray dried formulations was 2-10 μm under polarized light microscopy. All the formulations were physically stable for at least 3h when suspended in an aqueous vehicle composed of 1% methyl cellulose. This study demonstrates that DoE is a useful tool to optimize the spray drying process, and the B-90 can be used to efficiently produce amorphous solid dispersions with a limited quantity of drug substance available during drug discovery stages.
International Monetary Fund
1997-01-01
A central bank must decide on the frequency with which it will conduct open market operations and the variability in short-term money market that it will allow. The paper shows how the optimal operating procedure balances the value of attaining an immediate target and broadcasting the central bank's intentions against the informational advantages to the central bank of allowing the free play of market forces to reveal more of the information available to market participants.
Bouguecha, Salah T; Boubakri, Ali; Aly, Samir E; Al-Beirutty, Mohammad H; Hamdi, Mohamed M
2016-01-01
Membrane distillation (MD) is considered as a relatively high-energy requirement. To overcome this drawback, it is recommended to couple the MD process with solar energy as the renewable energy source in order to provide heat energy required to optimize its performance to produce permeate flux. In the present work, an original solar energy driven direct contact membrane distillation (DCMD) pilot plant was built and tested under actual weather conditions at Jeddah, KSA, in order to model and optimize permeate flux. The dependency of permeate flux on various operating parameters such as feed temperature (46.6-63.4°C), permeate temperature (6.6-23.4°C), feed flow rate (199-451L/h) and permeate flow rate (199-451L/h) was studied by response surface methodology based on central composite design approach. The analysis of variance (ANOVA) confirmed that all independent variables had significant influence on the model (where P-value <0.05). The high coefficient of determination (R(2) = 0.9644 and R(adj)(2) = 0.9261) obtained by ANOVA demonstrated good correlation between experimental and predicted values of the response. The optimized conditions, determined using desirability function, were T(f) = 63.4°C, Tp = 6.6°C, Q(f) = 451L/h and Q(p) = 451L/h. Under these conditions, the maximum permeate flux of 6.122 kg/m(2).h was achieved, which was close to the predicted value of 6.398 kg/m(2).h.
Optimización de la agudeza visual en las FAS Optimization of visual acuity in Spanish Armed Forces
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J. Medin Catoira
2011-06-01
Full Text Available Introducción: La existencia de una agudeza visual óptima es requerida para la mayor parte de las actividades del personal de las FAS, pero se hace estrictamente necesaria en el despliegue dentro del teatro de operaciones internacional. Material y Método: Hemos realizado un estudio sobre el registro de la agudeza visual en un grupo aleatorio (n = 54 durante los reconocimientos periódicos de permanencia realizados en nuestro centro. Resultados: Sólo 3 casos (5,56% reconocen ver mal; 20 (37,04% han utilizado corrección en algún momento de su vida; 12 (22,22% utilizan corrección; en 32 (60,38% sería altamente recomendable el uso de corrección. Ningún caso (0% de los usuarios de corrección posee corrección de repuesto (en gafas. Conclusión: Se hace incidencia en el control y registro de los parámetros visuales en el personal de las FAS, especialmente en actividades de riesgo y despliegue internacional.Introduction: The existence of an optimal visual acuity is required for most of the activities of the membrers of the Armed Forces, but it is strictly necessary in the deployment within the international theater. Materials and Methods: We conducted a study of visual acuity in a random group of periodical surveys in our center. Results: Only 3 cases (5.56% recognize look bad; 20 (37.04% have used correction at some point in their lives; 12 (22.22% used correction; in 32 cases (60.38% was highly recommended the use of correction. No cases (0% of users of correction has a duplicate of it (in glasses. Conclusions: The study suggests the need for better surveillance and control of visual parameters of the Armed Forces members, especially in risky activities and international deployment.
Au + Au central collisions at 150, 250 and 400 AMeV energies in QMD with relativistic forces
Németh, J; Feldmeier, H
1999-01-01
An extensive comparison of the recent experimental data published by the FOPI collaboration at GSI with the results of a relativistically covariant formulation of a QMD code is presented. For most of the quantities we find agreement with the experimental results showing that the derived force has a reasonable momentum dependence.
Optimizing Fracture Treatments in a Mississippian "Chat" Reservoir, South-Central Kansas
Energy Technology Data Exchange (ETDEWEB)
K. David Newell; Saibal Bhattacharya; Alan Byrnes; W. Lynn Watney; Willard Guy
2005-10-01
This project is a collaboration of Woolsey Petroleum Corporation (a small independent operator) and the Kansas Geological Survey. The project will investigate geologic and engineering factors critical for designing hydraulic fracture treatments in Mississippian ''chat'' reservoirs. Mississippian reservoirs, including the chat, account for 159 million m3 (1 billion barrels) of the cumulative oil produced in Kansas. Mississippian reservoirs presently represent {approx}40% of the state's 5.6*106m3 (35 million barrels) annual production. Although geographically widespread, the ''chat'' is a heterogeneous reservoir composed of chert, cherty dolomite, and argillaceous limestone. Fractured chert with micro-moldic porosity is the best reservoir in this 18- to 30-m-thick (60- to 100-ft) unit. The chat will be cored in an infill well in the Medicine Lodge North field (417,638 m3 [2,626,858 bbls] oil; 217,811,000 m3 [7,692,010 mcf] gas cumulative production; discovered 1954). The core and modern wireline logs will provide geological and petrophysical data for designing a fracture treatment. Optimum hydraulic fracturing design is poorly defined in the chat, with poor correlation of treatment size to production increase. To establish new geologic and petrophysical guidelines for these treatments, data from core petrophysics, wireline logs, and oil-field maps will be input to a fracture-treatment simulation program. Parameters will be established for optimal size of the treatment and geologic characteristics of the predicted fracturing. The fracturing will be performed and subsequent wellsite tests will ascertain the results for comparison to predictions. A reservoir simulation program will then predict the rate and volumetric increase in production. Comparison of the predicted increase in production with that of reality, and the hypothetical fracturing behavior of the reservoir with that of its actual behavior, will serve as tests of
Optimizing Security Force Generation
2009-06-01
occurs C. VARIABLES , ,r p tACS accessed Soldier for rank r 1 to 5 in TIG t at the beginning of period p [soldiers] , ,r p tETS end time...34The Mathematics of a Population Composed of k Stationary Strata Each Recruited from the Stratum Below and Supported at the Lowest Level by a Uniform...Sons, 1978. Vajda, S. "The Stratified Semi- Stationary Population." Biometrika, 1947: 243–254. 64 Walker, Steven C. Evaluating End Effects for
Kawaura, Kazuaki; Ogata, Yukino; Inoue, Masako; Honda, Sokichi; Soeda, Fumio; Shirasaki, Tetsuya; Takahama, Kazuo
2009-12-14
The antidepressant-like effect of tipepidine was studied in rats. Tipepidine at 20 and 40 mg/kg i.p. reduced immobility in the forced swimming test and tipepidine at 40 mg/kg, i.p. increased climbing in the test. The drug at 40 mg/kg, i.p. had no effect on the locomotor activity and motor coordination. These results suggest that tipepidine may be a novel drug with antidepressant-like activity.
Hashemi, Payman; Raeisi, Fatemeh; Ghiasvand, Ali Reza; Rahimi, Akram
2010-03-15
A reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method was developed for the preconcentration and direct HPLC determination of oleuropein in olive's processing wastewater (OPW) and olive leaves extracts. In conventional DLLME, the sedimented phase is a micro-drop of a chlorinated organic solvent that is not compatible with RP-HPLC. Therefore, solvent evaporation and reconstitution with an appropriate solvent is often required. In RP-DLLME, this problem was overcome by overturning the solvent polarity in the ordinary DLLME and replacing the organic solvent with water. A central composite chemometrics design was used for multivariate optimization of the effects of five different parameters influencing the extraction efficiency of the method. In the optimized conditions, a mixture of 1.4 mL of an ethyl acetate extract of sample and 40 microL water (pH 5.0) was rapidly injected into 5.3 mL of cyclohexane. After centrifugation of the formed cloudy mixture, a micro-drop of the aqueous phase was sedimented at the conical bottom of the centrifuge tube. This phase, that contained the preconcentrated and partially purified analyte, was directly injected into an RP-HPLC column for analysis. A mean extraction recovery of 102.5 (+/-4.5) % with enrichment factors exceeding 38, was obtained for five replicated analysis. The detection limit of the method (3 sigma) for OE was 0.02 microg L(-1) for OPW and 2 x 10(-3) mg kg(-1) for olive leaves samples. The results showed that, RP-DLLME is a promising technique which is quick, easily operated and can be directly coupled to HPLC.
Chauhan, Manvendra S; Kumar, Anil; Pathak, Kamla
2012-12-01
A nondisintegrating, floating asymmetric membrane capsule (FAMC) was developed to achieve site-specific osmotic flow of a highly water-soluble drug, ranitidine hydrochloride (RHCl), in a controlled manner. Solubility suppression of RHCl was achieved by the common ion effect, using optimized coated sodium chloride as a formulation component. The capsular wall of FAMC was prepared by the phase inversion process wherein the polymeric membrane was precipitated on glass pins by dipping them in a solution of cellulose acetate followed by quenching. Central composite design was utilized to investigate the influence of independent variables, namely, level(s) of membrane former, pore former, and osmogen, on percent cumulative drug release (response). The release mechanism of RHCl through FAMC was confirmed as osmotic pumping. The asymmetry of the membrane was characterized by scanning electron microscopy that revealed a dense nonporous outer region of membrane supported by an inner porous region. Differential scanning calorimetry indicated no incompatibility between the drug and excipients. In vitro drug release in three biorelevant media, pH 2.5 (low fed), pH 4.5 (intermediate fed), and pH 6.5 (high fed), demonstrated pH-independent release of RHCl (P > 0.05). Floating ability for 12 h of the optimized FAMC9 was visually examined during the in vitro release studies that showed maximal drug release with zero-order kinetics (r (2) = 0.9991). Thus, a novel osmotically regulated floating capsular system was developed for site-specific delivery of RHCl.
Mukhopadhyay, Somparna; Hazra, Lakshminarayan
2015-11-01
Resolution capability of an optical imaging system can be enhanced by reducing the width of the central lobe of the point spread function. Attempts to achieve the same by pupil plane filtering give rise to a concomitant increase in sidelobe intensity. The mutual exclusivity between these two objectives may be considered as a multiobjective optimization problem that does not have a unique solution; rather, a class of trade-off solutions called Pareto optimal solutions may be generated. Pareto fronts in the synthesis of lossless phase-only pupil plane filters to achieve superresolution with prespecified lower limits for the Strehl ratio are explored by using the particle swarm optimization technique.
M. Conradie; Smit, E.; Louw, M., Dr.; Prinsloo, M; L. Loubser; A. Wilsdorf
2004-01-01
Background and purpose: Physiotherapists frequently use central posterior-anterior (PA) joint mobilization techniques for assessing and managing spinal disorders. Manual examination findings provide the basis for the selection of treatment techniques. From the literature it is evident that the level of reliability varies when physiotherapists perform different mobilization techniques. Repeatability of mobilization techniques is important for better physiotherapy management. The aim of the stu...
Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.
2010-01-01
Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998
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Fatma Demirkaya-Miloglu
2014-09-01
Full Text Available Here, a spectrofluorimetric method for the determination of potassium losartan (PL in pharmaceutical products is described. The effects of critical parameters, pH, acid molarity, and temperature, on the fluorescence intensity of PL were analyzed, and these parameters were optimized using a central composite design (CCD. The highest fluorescent intensity at excitation (λex and emission (λem wavelengths of 248 nm and 410 nm, respectively, was achieved using 0.01 M sulfurous acid (pH 2 at 21.6 °C. Under optimum conditions, the method was linear from 0.025-0.5 µg/mL, with a reasonably high correlation coefficient (0.9993. Furthermore, the method was very sensitive (LOQ, 0.006, accurate (RE, ≤7.06, and precise (%RSD, ≤6.51. After development and validation of the method, samples containing PL were analyzed with this method, and the obtained data were statistically compared with those obtained with a previously published reference method using a two one-sided equivalence test (TOST. According to the data, the results from the proposed and reference assays were equivalent.
Jeong, Sung-Eun; Park, Jae-Kweon; Kim, Jeong-Dong; Chang, In-Jeong; Hong, Seong-Joo; Kang, Sung-Ho; Lee, Choul-Gyun
2008-12-01
Statistical experimental designs; involving (i) a fractional factorial design (FFD) and (ii) a central composite design (CCD) were applied to optimize the culture medium constituents for production of a unique antifreeze protein by the Antartic microalgae Chaetoceros neogracile. The results of the FFD suggested that NaCl, KCl, MgCl2, and Na2SiO3 were significant variables that highly influenced the growth rate and biomass production. The optimum culture medium for the production of an antifreeze protein from C. neogracile was found to be Kalleampersandrsquor;s artificial seawater, pH of 7.0ampersandplusmn;0.5, consisting of 28.566 g/l of NaCl, 3.887 g/l of MgCl2, 1.787 g/l of MgSO4, 1.308 g/l of CaSO4, 0.832 g/l of K2SO4, 0.124 g/l of CaCO3, 0.103 g/l of KBr, 0.0288 g/l of SrSO4, and 0.0282 g/l of H3BO3. The antifreeze activity significantly increased after cells were treated with cold shock (at -5oC) for 14 h. To the best of our knowledge, this is the first report demonstrating an antifreeze-like protein of C. neogracile.
Lovich, Jeffrey E.; Madrak, Sheila V.; Drost, Charles A.; Monatesti, Anthony J.; Casper, Dennis; Znari, Mohammed
2012-01-01
We studied the reproductive ecology of female Sonora mud turtles (Kinosternon sonoriense) at Montezuma Well, a chemically-challenging natural wetland in central Arizona, USA. Females matured between 115.5 and 125 mm carapace length (CL) and 36-54% produced eggs each year. Eggs were detected in X-radiographs from 23 April-28 September (2007-2008) and the highest proportion (56%) of adult females with eggs occurred in June and July. Clutch frequency was rarely more than once per year. Clutch size was weakly correlated with body size, ranged from 1-8 (mean = 4.96) and did not differ significantly between years. X-ray egg width ranged from 17.8-21.7 mm (mean 19.4 mm) and varied more among clutches than within. Mean X-ray egg width of a clutch did not vary significantly with CL of females, although X-ray pelvic aperture width increased with CL. We observed no evidence of a morphological constraint on egg width. In addition, greater variation in clutch size, relative to egg width, suggests that egg size is optimized in this hydrologically stable but chemically-challenging habitat. We suggest that the diversity of architectures exhibited by the turtle pelvis, and their associated lack of correspondence to taxonomic or behavioral groupings, explains some of the variation observed in egg size of turtles.
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Hessainia Zahia
2015-04-01
Full Text Available This paper focuses on the exploitation of the response surface methodology (RSM to determine optimum cutting conditions leading to minimum surface roughness and cutting force components. The technique of RSM helps to create an efficient statistical model for studying the evolution of surface roughness and cutting forces according to cutting parameters: cutting speed, feed rate and depth of cut. For this purpose, turning tests of hardened steel alloy (AISI 4140 (56 HRC were carried out using PVD – coated ceramic insert under different cutting conditions. The equations of surface roughness and cutting forces were achieved by using the experimental data and the technique of the analysis of variance (ANOVA. The obtained results are presented in terms of mean values and confidence levels. It is shown that feed rate and depth of cut are the most influential factors on surface roughness and cutting forces, respectively. In addition, it is underlined that the surface roughness is mainly related to the cutting speed, whereas depth of cut has the greatest effect on the evolution of cutting forces. The optimal machining parameters obtained in this study represent reductions about 6.88%, 3.65%, 19.05% in cutting force components (Fa, Fr, Ft, respectively. The latters are compared with the results of initial cutting parameters for machining AISI 4140 steel in the hard turning process.
Directory of Open Access Journals (Sweden)
Agnes Gagyi
2016-08-01
Full Text Available Joining a series of analyses of effects of othering, orientalism, or coloniality in East Central Europe, the paper asks how long-term structural-ideological effects of global hierarchies, as reflected in post-colonial contexts by the term “coloniality of power,” can be conceptualized for East Central Europe. In a case study of political polarization in post-socialist Hungary,it examines the effects of global integration, claiming that two dominant economic-political blocks formed along a division of vertical alliances related to integration with either Western or national capital. From those positions, they developed divergent political ideologies of development: modernization through Western integration, versus the protection of “national” wealth from Western capital and its local allies. While both propagated capitalist integration, they each needed to develop ideologies that appealed to electorates suffering the costs of integration. One framing of developmentalist emancipation promised Western modernity through rejection of popular, backward characteristics of the country, including nationalism. The other promised advancement in the global hierarchy through overcoming internal and external enemies of national development. These two, mutually reinforcing ideological positions, which I call“democratic antipopulism” and “antidemocratic populism,” denied the contradiction between elites’ and workers’ interest and perpetuated existing global hierarchies. Within the wider debate over cross-contextual applications of the notion of “coloniality of power,” and of emancipative efforts born from the “colonial wound,” the paper emphasizes the significance of the structural conditions, positions and alliances within which experiences of global domination are born and mobilized.
Martínez-Tossas, Luis A.; Churchfield, Matthew J.; Meneveau, Charles
2016-09-01
When representing the blade aerodynamics with rotating actuator lines, the computed forces have to be projected back to the CFD flow field as a volumetric body force. That has been done in the past with a geometrically simple uniform three-dimensional Gaussian at each point along the blade. We argue that the body force can be shaped in a way that better predicts the blade local flow field, the blade load distribution, and the formation of the tip/root vortices. In previous work, we have determined the optimal scales of circular and elliptical Gaussian kernels that best reproduce the local flow field in two-dimensions. In this work we extend the analysis and applications by considering the full three-dimensional blade to test our hypothesis in a highly resolved Large Eddy Simulation.
Reichard, Eric G.; Land, Michael; Crawford, Steven M.; Johnson, Tyler D.; Everett, Rhett; Kulshan, Trayle V.; Ponti, Daniel J.; Halford, Keith L.; Johnson, Theodore A.; Paybins, Katherine S.; Nishikawa, Tracy
2003-01-01
Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers, increased delivery of imported water, and increased use of reclaimed water. In order to improve the scientific basis for these water management activities, an extensive data collection program was undertaken, geohydrological and geochemical analyses were conducted, and ground-water flow simulation and optimization models were developed. In this project, extensive hydraulic, geologic, and chemical data were collected from new multiple-well monitoring sites. On the basis of these data and data compiled and collected from existing wells, the regional geohydrologic framework was characterized. For the purposes of modeling, the three-dimensional aquifer system was divided into four aquifer systems?the Recent, Lakewood, Upper San Pedro, and Lower San Pedro aquifer systems. Most pumpage in the two basins is from the Upper San Pedro aquifer system. Assessment of the three-dimensional geochemical data provides insight into the sources of recharge and the movement and age of ground water in the study area. Major-ion data indicate the chemical character of water containing less than 500 mg/L dissolved solids generally grades from calcium-bicarbonate/sulfate to sodium bicarbonate. Sodium-chloride water, high in dissolved solids, is present in wells near the coast. Stable isotopes of oxygen and hydrogen provide information on sources of recharge to the basin, including imported water and water originating in the San Fernando Valley, San Gabriel Valley, and the coastal plain and surrounding hills. Tritium and carbon-14 data provide information on relative ground-water ages. Water with
Valladares Alvarez, G; Galarza, J; Espinoza, J; Nieri, A; Makino, R; Berrocal, A; Grados, N
1989-01-01
In the present paper, the serologic markers of Hepatitis B virus were studied in 123 people belonging to the Hospital Central de la Fuerza Aérea del Perú that had been working in areas of high risk to get contact with this virus. The determination was done with the enzimo inmuno assay (EIA Abbot) and the results were the following: In 15 individuals (12.1%), at least one positive marker was found, evidence which proved to have been in contact with the virus in some moment of his life. Only one carrier (0.8%) was found, in 6 (4.8%) the presence of anti-HBc as only marker was found and in 8 (6.5%) the presence of Anti-HBc and Anti-HBs was observed which means post infection immunity. The great number of the individuals in which the markers were found, were male: 13 (16.0%) against only 2 (4.7%) female. There wasn't great difference with relation to the prevalency of markers according to the years of work like there has been observed in other greater series. It can be concluded that in this group the incidence of infection due to VHB was no greater than that of general population, which indicates us the little contact that they have had with the contaminating material during their professional life.
Menking, Kirsten M.
2015-05-01
Lacustrine sediments from the Estancia Basin of central New Mexico reveal decadal to millennial oscillations in the volume of Lake Estancia during Last Glacial Maximum (LGM) time. LGM sediments consist of authigenic carbonates, detrital clastics delivered to the lake in stream flow pulses, and evaporites that precipitated in mudflats exposed during lake lowstands and were subsequently blown into the lake. Variations in sediment mineralogy thus reflect changes in hydrologic balance and were quantified using Rietveld analysis of X-ray diffraction traces. Radiocarbon dates on ostracode valve calcite allowed the construction of mineralogical time series for the interval ~ 23,600 to ~ 18,300 ka, which were subjected to spectral analysis using REDFIT (Schulz and Mudelsee, 2002). Dominant periods of ~ 900, ~ 375, and ~ 265 yr are similar to cycles in Holocene 14C production reported for a variety of tree ring records, suggesting that the Lake Estancia sediments record variations in solar activity during LGM time. A prominent spectral peak with a period of ~ 88 yr appears to reflect the solar Gleissberg cycle and may help, along with the ~ 265 yr cycle, to explain an ongoing mystery about how Lake Estancia was able to undergo abrupt expansions without overflowing its drainage basin.
Indian Academy of Sciences (India)
J Swain; R K Shukla; A Raghunadha Rao; J K Panigrahi; N R Venkitachalam
2003-06-01
Time-series wind and wave measurements were carried out onboard INS Sagardhwani in the central Bay of Bengal during BOBMEX-99. Various other marine meteorological and oceanographic measurements relevant to monsoon studies were also collected simultaneously. The observed variations of wind and waves and the associated mixed layer depth (MLD) variability based on both temperature and density criteria at 3 hourly intervals are presented in this paper as a case study. At the time-series location (13°N, 87°E) wind varied between 6 and 16 m/s and the predominant direction was southwesterly. The significant wave height and period varied from 1.9 to 3.7m and 8 to 13 s respectively. Some of the available statistical predictive methods for the determination of MLD by forced mixing are utilized to test the extent of mechanical mixing within the top layer of water by the local wind and wave activity. The same is extended to formulate a new empirical relation for gross estimation of effective depth within which the sound energy is generally trapped during its transmission in the surface duct. The present analysis aiming for estimation of observed MLD variability (35 to 75 m) using the suggested simple empirical relation reveals that, the mixed layer variability observed during the experiment depends on both local ocean variability as well as remote forcing as reported earlier.
Energy Technology Data Exchange (ETDEWEB)
Omelyan, Igor, E-mail: omelyan@ualberta.ca, E-mail: omelyan@icmp.lviv.ua [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9 (Canada); Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8 (Canada); Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, Lviv 79011 (Ukraine); Kovalenko, Andriy, E-mail: andriy.kovalenko@nrc-cnrc.gc.ca [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9 (Canada); Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8 (Canada)
2013-12-28
We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics
Energy Technology Data Exchange (ETDEWEB)
Dellin, T.A.; Fish, M.J.; Yang, C.L.
1981-08-01
DELSOL2 is a revised and substantially extended version of the DELSOL computer program for calculating collector field performance and layout, and optimal system design for solar thermal central receiver plants. The code consists of a detailed model of the optical performance, a simpler model of the non-optical performance, an algorithm for field layout, and a searching algorithm to find the best system design. The latter two features are coupled to a cost model of central receiver components and an economic model for calculating energy costs. The code can handle flat, focused and/or canted heliostats, and external cylindrical, multi-aperture cavity, and flat plate receivers. The program optimizes the tower height, receiver size, field layout, heliostat spacings, and tower position at user specified power levels subject to flux limits on the receiver and land constraints for field layout. The advantages of speed and accuracy characteristic of Version I are maintained in DELSOL2.
Energy Technology Data Exchange (ETDEWEB)
Priyadarshi, Devinder [DAV Institute of Engineering and Technology, Jalandhar (India); Sharma, Rajesh Kumar [Institute of Technology, Hamirpur (India)
2016-03-15
Aluminium matrix composites (AMCs) now hold a significant share of raw materials in many applications. It is of prime importance to study the machinability of such composites so as to enhance their applicability. Sufficient work has been done for studying the machining of AMCs with particle reinforcements of micron range. This paper presents the study of AMCs with particle reinforcement of under micron range i.e. nanoparticles. This paper brings out the results of an experimental investigation of type and weight percent of nanoparticles on the tangential cutting force during turning operation. SiC, Gr and SiC-Gr (in equal proportions) were used with Al-6061 alloy as the matrix phase. The results indicate that composites with SiC require greater cutting force followed by hybrid and then Gr. Increase in the weight percent also significantly affected the magnitude of cutting force. RSM was used first to design and analyze the experiments and then to optimize the turning process and obtain optimal conditions of weight and type of reinforcements for turning operation.
Energy Technology Data Exchange (ETDEWEB)
Cervantes-de Gortari, J; Vidal-Santo, A.; Mendez-Lavielle, F.; Bautista-Godinez, O. [Departamento de Termoenergia, from Facultad de Ingenieria UNAM (Mexico)
2002-03-01
In this paper, a summary review of the current thermodynamic concepts related to the maximum power generation and minimum entropy production are presented. The results of the analysis are considered in Mexican power stations using conventional cycles and are compared with other power stations around the world. [Spanish] En este trabajo se revisa el analisis de maxima generacion de potencia que implica la minimizacion de la produccion de entropia en centrales generadoras de potencia. De acuerdo con los lineamientos mas recientes publicados en la literatura. Los conceptos y resultados del analisis se aplican a varias centrales mexicanas y se comparan con otras centrales en el mundo.
Energy Technology Data Exchange (ETDEWEB)
Cervantes de Gortari, J.; Vidal Santo, A.; Mendez Lavielle, F.; Bautista Godinez, O. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)
2002-03-01
In this paper, a summary review of the current thermodynamic concepts to the maximum power generation and minimum entropy production are presented. The results of the analysis are considered in Mexican power stations using conventional cycles and are compared with other power stations around the world. [Spanish] En este trabajo se revisa el analisis de maxima generacion de potencia que implica la minimizacion de la produccion de entropia en centrales generadoras de potencia, de acuerdo con los lineamientos mas recientes publicados en la literatura. Los conceptos y resultados del analisis se aplican a varias centrales mexicanas y se comparan con otras centrales en el mundo.
Institute of Scientific and Technical Information of China (English)
TANG Hua-ping; PENG Ya-qing
2005-01-01
A kind of active vibration control method was presented through optimal design of driving load of multi-body system with quick startup and brake. Dynamical equation of multi-body system with quick startup and brake was built, and mathematical model of representing vibration control was also set up according to the moving process from startup to brake. Then optimization vibration control model of system driving load was founded by applying theory of optimization control, which takes rigid body moving variable of braking moment as the known condition, and vibration control equation of multi-body system with quick startup and brake was converted into boundary value problem of differential equation. The transient control algorithm of vibration was put forward, which is the analysis basis for the further research. Theoretical analysis and calculation of numerical examples show that the optimal design method for the multi-body system driving load can decrease the vibration of system with duplication.
Energy Technology Data Exchange (ETDEWEB)
Espinosa G, J.M. [Central Nucleoelectrica Laguna Verde, Carretera Cardel-Nautla Km. 45.5, Municipio de Alto Lucero, Veracruz (Mexico)
2006-07-01
The Laguna Verde Central from the beginning of the commercial operation settled down as maximum priority 'the total safety in its operation' taking in consideration the so much experience of the good operation and of multiple recharges made in a sure and reliable way, and without separate us of the safety mystic of the CLV, but looking for to be better every day a new challenge it settled down 'to compare us with the best plants in the world' and certainly to work to classify us like one of them. For this we established a 4.0 year old plan (2003/2006) for the effectiveness all the processes in the power station that allowed us to measure our acting with the same parameters that settle down at international level (nuclear safety, industrial safety, radiological safety, capacity factor, readiness factor, cleaning of the power station, attachment to procedures, attention to the detail and certainly to be competitive in the economic aspect, summing up means to be good in all the aspects). All the above mentioned would allow us to qualify us as level 1 of WANO (world proprietors association of nuclear centrals) at the end of the year 2006 and to pass to be part of this select group. After analyzing the acting record of the power station, evaluating our technical and economic capacity, the location of the installation besides revising the international experiences was defined that one of the concepts that impact considerably so much to the capacity factors and availability besides the dose and production cost is the duration of the recharge periods, for this reason the present work is elaborated. (Author)
Penaud, Aurélie; Eynaud, Frédérique; Luise Voelker, Antje Helga; Turon, Jean-Louis
2016-09-01
New dinoflagellate cyst (dinocyst) analyses were carried out at high resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing for discussion of palaeohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dinocyst taxa, according to their (palaeo)ecological significance, shed light on significant sea-surface changes. Superimposed on the general decreasing pattern of dinocyst export to the seafloor over the last 50 ky, paralleling the general context of decreasing aeolian dust fertilization, a complex variability in dinocyst assemblages was detected at the millennial timescale. Enhanced fluvial discharges occurred during Greenland Interstadials (GIs), especially GI 1, 8 and 12, while enhanced upwelling cell dynamics were suggested during the Last Glacial Maximum and Heinrich Stadials. Finally, during the early Holocene, and more specifically during the Sapropel 1 interval (around 7-9 ka BP), we evidenced a strong decrease in dinocyst fluxes, which occurred synchronously to a strong reduction in Mediterranean Outflow Water strength and which we attributed to an advection of warm and nutrient-poor subtropical North Atlantic Central Waters. Over the last 50 ky, our study thus allows for capturing and documenting the fine tuning existing between terrestrial and marine realms in North Atlantic subtropical latitudes, in response to not only the regional climate pattern but also monsoonal forcing interfering during precession-driven Northern Hemisphere insolation maxima. This mechanism, well expressed during the Holocene, is superimposed on the pervasive role of the obliquity as a first major trigger for explaining migration of dinocyst productive centres in the NE Atlantic margin to the subtropical (temperate) latitudes during glacial (interglacial) periods.
Chiavico, Mattia; Raso, Luciano; Dorchies, David; Malaterre, Pierre-Olivier
2015-04-01
Seine river region is an extremely important logistic and economic junction for France and Europe. The hydraulic protection of most part of the region relies on four controlled reservoirs, managed by EPTB Seine-Grands Lacs. Presently, reservoirs operation is not centrally coordinated, and release rules are based on empirical filling curves. In this study, we analyze how a centralized release policy can face flood and drought risks, optimizing water system efficiency. The optimal and centralized decisional problem is solved by Stochastic Dual Dynamic Programming (SDDP) method, minimizing an operational indicator for each planning objective. SDDP allows us to include into the system: 1) the hydrological discharge, specifically a stochastic semi-distributed auto-regressive model, 2) the hydraulic transfer model, represented by a linear lag and route model, and 3) reservoirs and diversions. The novelty of this study lies on the combination of reservoir and hydraulic models in SDDP for flood and drought protection problems. The study case covers the Seine basin until the confluence with Aube River: this system includes two reservoirs, the city of Troyes, and the Nuclear power plant of Nogent-Sur-Seine. The conflict between the interests of flood protection, drought protection, water use and ecology leads to analyze the environmental system in a Multi-Objective perspective.
基于优化的电动车制动力分配%Optimization Based Braking Force Distribution for Electric Vehicles
Institute of Scientific and Technical Information of China (English)
郭金刚; 王军平; 曹秉刚
2011-01-01
The braking force distribution for an electric vehicle is described as a constrained optimization problem,in which both the energy recovery and brake performance are taken into account,and the genetic algorithm is used to solve the problem.The optimization problem of braking force distribution has a comprehensive consideration on the braking torque demand,the motor available braking torque,the maximum charge power of battery and brake performance requirement.Simulation results show that the optimization strategy takes advantage of the braking torque of the electric motor,making maximum recovery energy,together with good brake performance.Compared with the parallel strategy,our optimization strategy can obtain higher energy regeneration for typical driving cycles.%提出一种兼顾能量回收和制动性能要求的电动车制动力分配策略,建立了制动力分配的约束优化问题,并使用遗传算法来解决这一问题。制动力分配优化问题全面考虑了电机的可用制动转矩和最高转速限制、电池的最大充电功率限制以及汽车制动性能方面的要求。仿真结果表明：优化策略能够充分利用电机的制动转矩,保证汽车的制动性能,并使能量回收最大。与并联策略相比,采用优化方法,汽车在典型道路循环上的能量回收效率大大提高。
力伺服波浪补偿器控制研究及其性能优化%THE FORCE SERVO HEAVE COMPENSATOR CONTROL PERFORMANCE OPTIMIZATION
Institute of Scientific and Technical Information of China (English)
周明健; 王幼民
2015-01-01
Force Servo Heave Compensator is widely used in the field of ocean engineering, so the study of the control system of Force Servo Heave Compensator is of great significance. First of all, establish its mathematical model, using feed-forward compound control method to eliminate the disturbance interference that the load torque disturbance acting on the output shaft of the hydraulic motor. Based on the mathematical model of disturbance interference elimination system, analyzes the stability, the observability & the controllability of the system to prepare for the control performance optimization. Then, using pole assignment method to optimize the control performance of the system, get feedback matrix. Finally, the control performance of the optimized system is verified by the simulation, achieving the target of optimization design.%力伺服波浪补偿器广泛应用于海洋工程领域，研究力伺服波浪补偿器的控制系统具有重要意义。建立了其数学模型，运用前馈复合控制方法消除作用在液压马达输出轴的外负载力矩的扰动干扰。基于消去扰动干扰的系统的数学模型，分析了系统的稳定性、能观性、能控性，运用极点配置方法对系统的控制性能进行优化，得到反馈矩阵。通过仿真验证了优化后系统的控制性能达到了优化设计目标。
On Analysis of Motion Traj ectory of Plane Oscillator with Central Force%有心平面振子的轨迹分析
Institute of Scientific and Technical Information of China (English)
刘义东; 王建东; 刘普生
2014-01-01
Base on the model of the plane oscillator with central force,the differential equation of the mo-tion traj ectory has been obtained from Newton's second law and law of conservation of angular momentum in this work.Following the numerical simulation,we have found the periodic change of the motion traj ec-tory which is limited in an annular region with radius of inner and outer boundaries given analytically.Fur-ther more,the variation of the radii of the outer boundary and the cycle of the motion traj ectory with a constraint parameter is detailed.This work is illuminative to mechanics in college physics.%以有心平面振子为模型，运用牛顿第二定律和角动量守恒定律，给出了其轨迹满足的微分方程；采用数值计算方法得到周期性变化的振子运动轨迹，并给出振子运动的环形区域的内外半径的解析表达式；进一步地，还讨论了环形区域外半径和轨迹周期随约束参数的变化特征。
Directory of Open Access Journals (Sweden)
Yu.V. Kalyuzhnyi
2012-06-01
Full Text Available The liquid-gas phase diagram for polydisperse dipolar hard-sphere fluid with polydispersity in the hard-sphere size and dipolar moment is calculated using extension of the recently proposed thermodynamic perturbation theory for central force (TPT-CF associating potential. To establish the connection with the phase behavior of ferrocolloidal dispersions it is assumed that the dipole moment is proportional to the cube of the hard-sphere diameter. We present and discuss the full phase diagram, which includes cloud and shadow curves, binodals and distribution functions of the coexisting daughter phases at different degrees of the system polydispersity. In all cases studied polydispersity increases the region of the phase instability and shifts the critical point to the higher values of the temperature and density. The larger size particles always fractionate to the liquid phase and the smaller size particles tend to move to the gas phase. At relatively high values of the system polydispersity three-phase coexistence is observed.
Hamid Tebassi; Mohamed Athmane Yallese; Riad Khettabi; Salim Belhadi; Ikhlas Meddour; Francois Girardin
2016-01-01
Nickel based super alloys are excellent for several applications and mainly in structural components submitted to high temperatures owing to their high strength to weight ratio, good corrosion resistance and metallurgical stability such as in cases of jet engine and gas turbine components. The current work presents the experimental investigations of the cutting parameters effects (cutting speed, depth of cut and feed rate) on the surface roughness, cutting force components, productivity and p...
Rozvany, G. I. N.; Sobieszczanski-Sobieski, J.
1992-01-01
In new, iterative continuum-based optimality criteria (COC) methods, the strain in the adjoint structure becomes non-unique if the number of active local constraints is greater than the number of design variables for an element. This brief note discusses the use of smooth envelope functions (SEFs) in overcoming economically computational problems caused by the above non-uniqueness.
Thornburg, Jonathan
2010-01-01
If a small "particle" of mass $\\mu M$ (with $\\mu \\ll 1$) orbits a Schwarzschild or Kerr black hole of mass $M$, the particle is subject to an $\\O(\\mu)$ radiation-reaction "self-force". Here I argue that it's valuable to compute this self-force highly accurately (relative error of $\\ltsim 10^{-6}$) and efficiently, and I describe techniques for doing this and for obtaining and validating error estimates for the computation. I use an adaptive-mesh-refinement (AMR) time-domain numerical integration of the perturbation equations in the Barack-Ori mode-sum regularization formalism; this is efficient, yet allows easy generalization to arbitrary particle orbits. I focus on the model problem of a scalar particle in a circular geodesic orbit in Schwarzschild spacetime. The mode-sum formalism gives the self-force as an infinite sum of regularized spherical-harmonic modes $\\sum_{\\ell=0}^\\infty F_{\\ell,\\reg}$, with $F_{\\ell,\\reg}$ (and an "internal" error estimate) computed numerically for $\\ell \\ltsim 30$ and estimated ...
Matsuo, Ryota; Kobayashi, Suguru; Yamagishi, Miki; Ito, Etsuro
2011-03-15
Terrestrial pulmonates can learn olfactory-aversion tasks and retain them in their long-term memory. To elucidate the cellular mechanisms underlying learning and memory, researchers have focused on both the peripheral and central components of olfaction: two pairs of tentacles (the superior and inferior tentacles) and a pair of procerebra, respectively. Data from tentacle-amputation experiments showed that either pair of tentacles is sufficient for olfactory learning. Results of procerebrum lesion experiments showed that the procerebra are necessary for olfactory learning but that either one of the two procerebra, rather than both, is used for each olfactory learning event. Together, these data suggest that there is a redundancy in the structures of terrestrial pulmonates necessary for olfactory learning. In our commentary we exemplify and discuss functional optimization and structural redundancy in the sensory and central organs involved in olfactory learning and memory in terrestrial pulmonates.
Energy Technology Data Exchange (ETDEWEB)
Cortes Campos, Carlos Cristobal [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Montes Tadeo, Jose Luis [Instituto Nacional de Investigaciones Nucleares (ININ), Salazar (Mexico)
1991-12-31
It is described, in general terms, the procedure that is followed to accomplish the optimization of the recharge design, and an example is shown where this procedure was applied for the analysis of the type BWR reactor of Unit No. 1 of the Laguna Verde Nuclear Power Station. [Espanol] Se describe en terminos generales el procedimiento que se sigue para realizar la optimacion del diseno de recargas, y se muestra un ejemplo en el que se utilizo dicho procedimiento para el analisis del reactor tipo BWR de la unidad 1, de la Central Laguna Verde (CLV).
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).
Directory of Open Access Journals (Sweden)
Mohammad Faranoush
2013-10-01
Full Text Available Background: Labeling, gathering mutual information, clustering and classificationof central nervous system tumors may assist in predicting not only distinct diagnosesbased on tumor-specific features but also prognosis. This study evaluates the epidemi-ological features of central nervous system tumors in children who referred to Mahak’sPediatric Cancer Treatment and Research Center in Tehran, Iran.Methods: This cohort (convenience sample study comprised 198 children (≤15years old with central nervous system tumors who referred to Mahak's PediatricCancer Treatment and Research Center from 2007 to 2010. In addition to the descriptiveanalyses on epidemiological features and mutual information, we used the LeastSquares Support Vector Machines method in MATLAB software to propose apreliminary predictive model of pediatric central nervous system tumor feature-labelanalysis. Results:Of patients, there were 63.1% males and 36.9% females. Patients' mean±SDage was 6.11±3.65 years. Tumor location was as follows: supra-tentorial (30.3%, infra-tentorial (67.7% and 2% (spinal. The most frequent tumors registered were: high-gradeglioma (supra-tentorial in 36 (59.99% patients and medulloblastoma (infra-tentorialin 65 (48.51% patients. The most prevalent clinical findings included vomiting,headache and impaired vision. Gender, age, ethnicity, tumor stage and the presence ofmetastasis were the features predictive of supra-tentorial tumor histology.Conclusion: Our data agreed with previous reports on the epidemiology of centralnervous system tumors. Our feature-label analysis has shown how presenting features maypartially predict diagnosis. Timely diagnosis and management of central nervous systemtumors can lead to decreased disease burden and improved survival. This may be furtherfacilitated through development of partitioning, risk prediction and prognostic models.
Deino, A.L.; Kingston, J.D.; Glen, J.M.; Edgar, R.K.; Hill, A.
2006-01-01
The fluviolacustrine sedimentary sequence of the Chemeron Formation exposed in the Barsemoi River drainage, Tugen Hills, Kenya, contains a package of five successive diatomite/fluvial cycles that record the periodic development of freshwater lakes within the axial portion of the Central Kenya Rift. The overwhelming abundance in the diatomite of planktonic species of the genera Aulacoseira and Stephanodiscus, and the virtual absence of benthic littoral diatoms and detrital material indicate areally extensive, deep lake systems. A paleomagnetic reversal stratigraphy has been determined and chronostratigraphic tie points established by 40Ar/39Ar dating of intercalated tuffs. The sequence spans the interval 3.1-2.35??Ma and bears a detailed record of the Gauss/Matuyama paleomagnetic transition. The 40Ar/39Ar age for this boundary of 2.589 ?? 0.003??Ma can be adjusted to concordance with the Astronomical Polarity Time Scale (APTS) on the basis of an independent calibration to 2.610??Ma, 29??kyr older than the previous APTS age. The diatomites recur at an orbital precessional interval of 23??kyr and are centered on a 400-kyr eccentricity maximum. It is concluded that these diatomite/fluvial cycles reflect a narrow interval of orbitally forced wet/dry climatic conditions that may be expressed regionally across East Africa. The timing of the lacustrine pulses relative to predicted insolation models favors origination of moisture from the northern Africa monsoon, rather than local circulation driven by direct equatorial insolation. This moisture event at 2.7-2.55??Ma, and later East African episodes at 1.9-1.7 and 1.1-0.9??Ma, are approximately coincident with major global climatic and oceanographic events. ?? 2006 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Deswati
2016-06-01
Full Text Available This work describes a procedure for the simultaneous determination of cadmium in fruit and vegetable samples using adsorptive stripping voltammetry of complexes with calcon at a hanging mercury drop electrode (HMDE has been optimized using central composite design (CCD. The selection of the experimental conditions was made using experimental of the influence of several parameters were studied : variations of calcon concentration, pH, accumulation potential and accumulation time. The design experiment was a central composite design with 4 factors/variables, 3 levels and 31 treatment combinations. From analysis of variance, it was decided to accept the second-order model and the independent variable, concluded that a significant effect on the response variable (peak current. Based on data analysis with central composite design, the determination of cadmium obtained optimum conditions were : calcon concentration 0.8435 mM, pH 8.0047, accumulation potential -0.6346 Volt and accumulation time 81.85 seconds with a maximum peak current 61.8146 nA. At the optimum condition were obtained relative standard deviation 0.84%, recovery 98.88%, the linear range up to 110 µg/L, limit of detection 1.009 µg/L and LOQ 3.363 µg/L. The procedure was successfully applied to the determination of cadmium in fruit and vegetable samples without prior treatment.
Directory of Open Access Journals (Sweden)
Mina Yazdanpanah
2014-06-01
Full Text Available Evaluating the capability of electrospinning method as an efficient versatile approach for fabrication of fibers, a central composite design (CCD model was used to design an experimental program for investigation of effective in production of poly (vinyl alcohol (PVA fibers fabricated from aqueous solutions of PVA. The studied variables were polymer solution concentration, applied voltage, distance between nozzle and collector plate and flow rate of solution injection. The influence of these parameters on diameter and morphology of obtained PVA fibers was studied by SEM analysis. Among all factors, concentration would strongly affect the fiber diameter.
Directory of Open Access Journals (Sweden)
Maoinser Mohd Azuwan
2014-07-01
Full Text Available Drilling hybrid fiber reinforced polymer (HFRP composite is a novel approach in fiber reinforced polymer (FRP composite machining studies as this material combining two different fibers in a single matrix that resulted in considerable improvement in mechanical properties and cost saving as compared to conventional fiber composite material. This study presents the development and optimized way of drilling HFRP composite at various drilling parameters such as drill point angle, feed rate and cutting speed by using the full factorial design experiment with the combination of analysis of variance (ANOVA approach and signal to noise (S/N ratio analysis. The results identified optimum drilling parameters for drilling the HFRP composite using small drill point angle at low feed rate and medium cutting speed that resulted in lower thrust force.
Sands, David C; Morris, Cindy E; Dratz, Edward A; Pilgeram, Alice
2009-11-01
High-yielding cereals and other staples have produced adequate calories to ward off starvation for much of the world over several decades. However, deficiencies in certain amino acids, minerals, vitamins and fatty acids in staple crops, and animal diets derived from them, have aggravated the problem of malnutrition and the increasing incidence of certain chronic diseases in nominally well-nourished people (the so-called diseases of civilization). Enhanced global nutrition has great potential to reduce acute and chronic disease, the need for health care, the cost of health care, and to increase educational attainment, economic productivity and the quality of life. However, nutrition is currently not an important driver of most plant breeding efforts, and there are only a few well-known efforts to breed crops that are adapted to the needs of optimal human nutrition. Technological tools are available to greatly enhance the nutritional value of our staple crops. However, enhanced nutrition in major crops might only be achieved if nutritional traits are introduced in tandem with important agronomic yield drivers, such as resistance to emerging pests or diseases, to drought and salinity, to herbicides, parasitic plants, frost or heat. In this way we might circumvent a natural tendency for high yield and low production cost to effectively select against the best human nutrition. Here we discuss the need and means for agriculture, food processing, food transport, sociology, nutrition and medicine to be integrated into new approaches to food production with optimal human nutrition as a principle goal.
Goldman, Jennifer G; Holden, Samantha; Bernard, Bryan; Ouyang, Bichun; Goetz, Christopher G; Stebbins, Glenn T
2013-12-01
The recently proposed Movement Disorder Society (MDS) Task Force diagnostic criteria for mild cognitive impairment in Parkinson's disease (PD-MCI) represent a first step toward a uniform definition of PD-MCI across multiple clinical and research settings. However, several questions regarding specific criteria remain unanswered, including optimal cutoff scores by which to define impairment on neuropsychological tests. Seventy-six non-demented PD patients underwent comprehensive neuropsychological assessment and were classified as PD-MCI or PD with normal cognition (PD-NC). The concordance of PD-MCI diagnosis by MDS Task Force Level II criteria (comprehensive assessment), using a range of standard deviation (SD) cutoff scores, was compared with our consensus diagnosis of PD-MCI or PD-NC. Sensitivity, specificity, and positive and negative predictive values were examined for each cutoff score. PD-MCI subtype classification and distribution of cognitive domains impaired were evaluated. Concordance for PD-MCI diagnosis was greatest for defining impairment on neuropsychological tests using a 2 SD cutoff score below appropriate norms. This cutoff also provided the best discriminatory properties for separating PD-MCI from PD-NC compared with other cutoff scores. With the MDS PD-MCI criteria, multiple domain impairment was more frequent than single domain impairment, with predominant executive function, memory, and visuospatial function deficits. Application of the MDS Task Force PD-MCI Level II diagnostic criteria demonstrates good sensitivity and specificity at a 2 SD cutoff score. The predominance of multiple domain impairment in PD-MCI with the Level II criteria suggests not only influences of testing abnormality requirements, but also the widespread nature of cognitive deficits within PD-MCI.
McNamara, Robert K; Able, Jessica A; Liu, Yanhong; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Lipton, Jack W
2013-12-01
While translational evidence suggests that long-chain omega-3 fatty acid status is positively associated with the efficacy of selective serotonin reuptake inhibitor drugs, the neurochemical mechanisms mediating this interaction are not known. Here, we investigated the effects of dietary omega-3 (n-3) fatty acid insufficiency on the neurochemical and behavioral effects of chronic fluoxetine (FLX) treatment. Female rats were fed diets with (CON, n=56) or without (DEF, n=40) the n-3 fatty acids during peri-adolescent development (P21-P90), and one half of each group was administered FLX (10mg/kg/day) for 30days (P60-P90) prior to testing. In adulthood (P90), regional brain serotonin (5-HT) and 5-hydroxyindoleacetic (5-HIAA) concentrations, presynaptic markers of 5-HT neurotransmission, behavioral responses in the forced swim test (FST), and plasma FLX and norfluoxetine (NFLX) concentrations were investigated. Peri-adolescent n-3 insufficiency led to significant reductions in cortical docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (-25%, p≤0.0001) and DEF+FLX (-28%, p≤0.0001) rats. Untreated DEF rats exhibited significantly lower regional 5-HIAA/5-HT ratios compared with untreated CON rats, but exhibited similar behavioral responses in the FST. In both CON and DEF rats, chronic FLX treatment similarly and significantly decreased 5-HIAA concentrations and the 5-HIAA/5-HT ratio in the hypothalamus, hippocampus, and nucleus accumbens, brainstem tryptophan hydroxylase-2 mRNA expression, and immobility in the FST. While the FLX-induced reduction in 5-HIAA concentrations in the prefrontal cortex was significantly blunted in DEF rats, the reduction in the 5-HIAA/5-HT ratio was similar to CON rats. Although plasma FLX and NFLX levels were not significantly different in DEF and CON rats, the NFLX/FLX ratio was significantly lower in DEF+FLX rats. These preclinical data demonstrate that n-3 fatty acid deficiency does not significantly reduce the effects of chronic
Institute of Scientific and Technical Information of China (English)
WANG Chun-ling; SHEN Shuang-he; ZHANG Shu-yu; LI Qiao-zhen; YAO Yu-bi
2015-01-01
Potato grows in most part of China, it achieves higher yield and better quality in Gansu Province than in others. With global warming, its growth duration has been prolonged and sowing date become earlier than before. Therefore, to regulate its sowing date and growing period is of great signiifcance for better harvest. In this study, experiments were conducted with six sowing-date treatments of potato in Dingxi, which is in the Loess Plateau of central Gansu Province in Northwest China in 2010. The growth period, morphological index and change in yield and their relationships with temperature, precipitation, and other climatic factors were investigated for each treatment. Results show that the crop with different sowing dates experienced different climate conditions, leading to distinct growth duration, plant height, and leaf area index. The growth duration was shortened due to a delay in sowing date. For each 15-day delay in sowing, the growth duration was reduced by 12 days on average. A signiifcant linear relationship was found between numbers of days either from seeding to emergence or from lfowering to harvest and mean temperature over the corresponding period. Dry matter accumulation, tuber fresh weight, and ifnal yield were al decreased because of insufifcient cumulative temperature over the shorter growing periods. Marked differences in tuber yield were discovered among the six treatments of sowing date, the potato planted on May 27 giving the highest yield. The potato planted either earlier or later would produce invariably lower yield than the treatment of May 27. Late May therefore can be taken as the optimum sowing time of potato in this region because the crop can ful y utilize thermal resource. We conclude that to postpone sowing time is a good practice for potato production to adapt to climate warming in the Loess Plateau of central Gansu, China.
Directory of Open Access Journals (Sweden)
Sandeep Sonawane
2016-11-01
Full Text Available A stability-indicating LC method was developed and validated for the determination of luliconazole in bulk and cream formulation. Luliconazole was exposed to acid, alkali and water hydrolysis, oxidation effect by hydrogen peroxide, dry heat and photolytic conditions. Full factorial design was used during forced degradation experiments and the factors/combination of factors which were most likely to effect degradation of luliconazole under various conditions were identified and further were optimized using surface response curve. Drug was found to be stable under wet heat and dry heat conditions, but substantial degradation was observed under acid, alkali, oxidative and photolytic conditions. Drug and its degradation products were optimally resolved on HiQ sil C-18HS (250 × 4.6 mm, 5 μm column with the mobile phase consisting of methanol and water (80:20, v/v at a flow rate of 1 mL/min, detection was performed at 296 nm. The procedure was validated for specificity, linearity, accuracy and precision. There was no interference of excipients and degradation products in the determination of active pharmaceutical ingredient. The method was accurate and precise and the response was found to be linear in the range of 2–14 μg/mL. The method was found to be simple and fast by making use of experimental design.
Energy Technology Data Exchange (ETDEWEB)
Narayanan, Badri; Sasikumar, Kiran; Mei, Zhi-Gang; Kinaci, Alper; Sen, Fatih G.; Davis, Michael J.; Gray, Stephen K.; Chan, Maria K. Y.; Sankaranarayanan, Subramanian K. R. S.
2016-07-07
Zirconium nitride (ZrN) exhibits exceptional mechanical, chemical, and electrical properties, which make it attractive for a wide range of technological applications, including wear-resistant coatings, protection from corrosion, cutting/shaping tools, and nuclear breeder reactors. Despite its broad usability, an atomic scale understanding of the superior performance of ZrN, and its response to external stimuli, for example, temperature, applied strain, and so on, is not well understood. This is mainly due to the lack of interatomic potential models that accurately describe the interactions between Zr and N atoms. To address this challenge, we develop a modified embedded atom method (MEAM) interatomic potential for the Zr–N binary system by training against formation enthalpies, lattice parameters, elastic properties, and surface energies of ZrN (and, in some cases, also Zr3N4) obtained from density functional theory (DFT) calculations. The best set of MEAM parameters are determined by employing a multiobjective global optimization scheme driven by genetic algorithms. Our newly developed MEAM potential accurately reproduces structure, thermodynamics, energetic ordering of polymorphs, as well as elastic and surface properties of Zr–N compounds, in excellent agreement with DFT calculations and experiments. As a representative application, we employed molecular dynamics simulations based on this MEAM potential to investigate the atomic scale mechanisms underlying fracture of bulk and nanopillar ZrN under applied uniaxial strains, as well as the impact of strain rate on their mechanical behavior. These simulations indicate that bulk ZrN undergoes brittle fracture irrespective of the strain rate, while ZrN nanopillars show quasi-plasticity owing to amorphization at the crack front. The MEAM potential for Zr–N developed in this work is an invaluable tool to investigate atomic-scale mechanisms underlying the response of ZrN to external stimuli (e.g, temperature
Kamali, Hossein; Jalilvand, Mohammad Reza; Aminimoghadamfarouj, Noushin
2012-06-01
Essential oil components were extracted from lavandin (Lavandula hybrida) flowers using pressurized fluid extraction. A central composite design was used to optimize the effective extraction variables. The chemical composition of extracted samples was analyzed by a gas chromatograph-flame ionization detector column. For achieving 100% extraction yield, the temperature, pressure, extraction time, and the solvent flow rate were adjusted at 90.6°C, 63 bar, 30.4 min, and 0.2 mL/min, respectively. The results showed that pressurized fluid extraction is a practical technique for separation of constituents such as 1,8-cineole (8.1%), linalool (34.1%), linalyl acetate (30.5%), and camphor (7.3%) from lavandin to be applied in the food, fragrance, pharmaceutical, and natural biocides industries.
Garcia-Barrantes, Pedro M; Cho, Hyekyung P; Blobaum, Anna L; Niswender, Colleen M; Conn, P Jeffrey; Lindsley, Craig W
2015-11-15
This Letter describes the lead optimization of the VU0486321 series of mGlu1 positive allosteric modulators (PAMs). While first generation PAMs from Roche were reported in the late 1990s, little effort has focused on the development of mGlu1 PAMs since. New genetic data linking loss-of-function mutant mGlu1 receptors to schizophrenia, bipolar disorder and other neuropsychiatric disorders has rekindled interest in the target, but the ideal in vivo probe, for example, with good PK, brain penetration and low plasma protein binding, for robust target validation has been lacking. Here we describe the first modifications to the central aryl core of the VU0486321 series, where robust SAR was noted. Moreover, structural variants were identified that imparted selectivity (up to >793-fold) versus mGlu4.
Azari, Ali; Mesdaghinia, Alireza; Ghanizadeh, Ghader; Masoumbeigi, Hossein; Pirsaheb, Meghdad; Ghafari, Hamid Reza; Khosravi, Touba; Sharafi, Kiomars
2016-09-01
The aim of this study is to evaluate central composite design (CCD) and the Taguchi technique in the adsorption process. Contact time, initial concentration, and pH were selected as the variables, and the removal efficiency of Pb was chosen for the designated response. In addition, face-centered CCD and the L9 orthogonal array were used for the experimental design. The result indicated that, at optimum conditions, the removal efficiency of Pb was 80%. However, the value of R(2) was greater than 0.95 for both the CCD and Taguchi techniques, which revealed that both techniques were suitable and in conformity with each other. Moreover, the results of analysis of variance and Prob > F designated model with the experimental results. The probability of classifying the contributing variables by giving a percentage of the response quantity (Pb removal) made the Taguchi model an appropriate method for examining the effectiveness of different factors. pH was evaluated as the best input factor as it contributed 66.2% of Pb removal. The Taguchi technique was additionally confirmed by three-dimensional contour plots of CCD. Consequently, the Taguchi method with nine experimental runs and easy interaction plots is an appropriate substitute for CCD for several chemical engineering functions.
Colombié, Sophie; Nazaret, Christine; Bénard, Camille; Biais, Benoît; Mengin, Virginie; Solé, Marion; Fouillen, Laëtitia; Dieuaide-Noubhani, Martine; Mazat, Jean-Pierre; Beauvoit, Bertrand; Gibon, Yves
2015-01-01
Modelling of metabolic networks is a powerful tool to analyse the behaviour of developing plant organs, including fruits. Guided by our current understanding of heterotrophic metabolism of plant cells, a medium-scale stoichiometric model, including the balance of co-factors and energy, was constructed in order to describe metabolic shifts that occur through the nine sequential stages of Solanum lycopersicum (tomato) fruit development. The measured concentrations of the main biomass components and the accumulated metabolites in the pericarp, determined at each stage, were fitted in order to calculate, by derivation, the corresponding external fluxes. They were used as constraints to solve the model by minimizing the internal fluxes. The distribution of the calculated fluxes of central metabolism were then analysed and compared with known metabolic behaviours. For instance, the partition of the main metabolic pathways (glycolysis, pentose phosphate pathway, etc.) was relevant throughout fruit development. We also predicted a valid import of carbon and nitrogen by the fruit, as well as a consistent CO2 release. Interestingly, the energetic balance indicates that excess ATP is dissipated just before the onset of ripening, supporting the concept of the climacteric crisis. Finally, the apparent contradiction between calculated fluxes with low values compared with measured enzyme capacities suggest a complex reprogramming of the metabolic machinery during fruit development. With a powerful set of experimental data and an accurate definition of the metabolic system, this work provides important insight into the metabolic and physiological requirements of the developing tomato fruits.
Novitasari, D.; Indartono, Y. S.; Rachmidha, T. D.; Reksowardojo, I. K.; Irsyad, M.
2017-03-01
Nyamuk Island in Karimunjawa District is one of the regions in Java that has no access to electricity grid. The electricity in Nyamuk Island relies on diesel engine which is managed by local government and only operated for 6 hours per day. It occurs as a consequence of high fuel cost. A study on smart micro grid system based on renewable energy was conducted in Combustion Engine and Propulsion System Laboratory of Institut Teknologi Bandung by using 1 kWp solar panels and a 3 kW bio based diesel engine. The fuels used to run the bio based diesel engine were diesel, virgin coconut oil and pure palm oil. The results show that the smart grid system run well at varying load and also with different fuel. Based on the experiments, average inverter efficiency was about 87%. This experiments proved that the use of biofuels had no effects to the overall system performance. Based on the results of prototype experiments, this paper will focus on design and optimization of smart micro grid system using HOMER software for Nyamuk Island. The design consists of (1) a diesel engine existing in Nyamuk Island whose fuel was diesel, (2) a lister engine whose fuel was from vegetable oil from Callophyllum inophyllum, (3) solar panels, (4) batteries and (5) converter. In this simulation, the existing diesel engine was set to operate 2 hours per day, while operating time of the lister engine has been varied with several scenarios. In scenario I, the lister engine was operated 5 hours per day, in scenario II the lister engine was operated 24 hours per day and in scenario III the lister engine was operated 8 hours per week in the weekend. In addition, a design using a modified diesel engine was conducted as well with an assumption that the modified cost was about 10% of new diesel engine cost. By modifying the diesel engine, the system will not need a lister engine. Assessments has been done to evaluate the designs, and the result shows that the optimal value obtains by the lister engine
Ghaedi, M; Dashtian, K; Ghaedi, A M; Dehghanian, N
2016-05-11
The aim of this work is the study of the predictive ability of a hybrid model of support vector regression with genetic algorithm optimization (GA-SVR) for the adsorption of malachite green (MG) onto multi-walled carbon nanotubes (MWCNTs). Various factors were investigated by central composite design and optimum conditions was set as: pH 8, 0.018 g MWCNTs, 8 mg L(-1) dye mixed with 50 mL solution thoroughly for 10 min. The Langmuir, Freundlich, Temkin and D-R isothermal models are applied to fitting the experimental data, and the data was well explained by the Langmuir model with a maximum adsorption capacity of 62.11-80.64 mg g(-1) in a short time at 25 °C. Kinetic studies at various adsorbent dosages and the initial MG concentration show that maximum MG removal was achieved within 10 min of the start of every experiment under most conditions. The adsorption obeys the pseudo-second-order rate equation in addition to the intraparticle diffusion model. The optimal parameters (C of 0.2509, σ(2) of 0.1288 and ε of 0.2018) for the SVR model were obtained based on the GA. For the testing data set, MSE values of 0.0034 and the coefficient of determination (R(2)) values of 0.9195 were achieved.
Daneshian, Jahanbakhsh; Ramezani Dana, Leila; Sadler, Peter
2017-01-01
Benthic foraminifera species commonly outnumber planktic species in the type area of the Lower Miocene Qom Formation, in north central Iran, where it records the Tethyan link between the eastern Mediterranean and Indo- Pacific provinces. Because measured sections preserve very different sequences of first and last occurrences of these species, no single section provides a completely suitable baseline for correlation. To resolve this problem, we combined bioevents from three stratigraphic sections into a single composite sequence by constrained optimization (CONOP). The composite section arranges the first and last appearance events (FAD and LAD) of 242 foraminifera in an optimal order that minimizes the implied diachronism between sections. The composite stratigraphic ranges of the planktic foraminifera support a practical biozonation which reveals substantial local changes of accumulation rate during Aquitanian to Burdigalian times. Traditional biozone boundaries emerge little changed but an order of magnitude more correlations can be interpolated. The top of the section at Dobaradar is younger than previously thought and younger than sections at Dochah and Tigheh Reza-Abad. The latter two sections probably extend older into the Aquitanian than the Dobaradar section, but likely include a hiatus near the base of the Burdigalian. The bounding contacts with the Upper Red and Lower Red Formations are shown to be diachronous.
Energy Technology Data Exchange (ETDEWEB)
Modiri, A; Gu, X; Hagan, A; Sawant, A [UT Southwestern Medical Center, Dallas, TX (United States)
2015-06-15
Purpose: Patients presenting with large and/or centrally-located lung tumors are currently considered ineligible for highly potent regimens such as SBRT due to concerns of toxicity to normal tissues and organs-at-risk (OARs). We present a particle swarm optimization (PSO)-based 4D planning technique, designed for MLC tracking delivery, that exploits the temporal dimension as an additional degree of freedom to significantly improve OAR-sparing and reduce toxicity to levels clinically considered as acceptable for SBRT administration. Methods: Two early-stage SBRT-ineligible NSCLC patients were considered, presenting with tumors of maximum dimensions of 7.4cm (central-right lobe; 1.5cm motion) and 11.9cm (upper-right lobe; 1cm motion). In each case, the target and normal structures were manually contoured on each of the ten 4DCT phases. Corresponding ten initial 3D-conformal plans (Pt#1: 7-beams; Pt#2: 9-beams) were generated using the Eclipse planning system. Using 4D-PSO, fluence weights were optimized over all beams and all phases (70 and 90 apertures for Pt1&2, respectively). Doses to normal tissues and OARs were compared with clinicallyestablished lung SBRT guidelines based on RTOG-0236. Results: The PSO-based 4D SBRT plan yielded tumor coverage and dose—sparing for parallel and serial OARs within the SBRT guidelines for both patients. The dose-sparing compared to the clinically-delivered conventionallyfractionated plan for Patient 1 (Patient 2) was: heart Dmean = 11% (33%); lung V20 = 16% (21%); lung Dmean = 7% (20%); spinal cord Dmax = 5% (16%); spinal cord Dmean = 7% (33%); esophagus Dmax = 0% (18%). Conclusion: Truly 4D planning can significantly reduce dose to normal tissues and OARs. Such sparing opens up the possibility of using highly potent and effective regimens such as lung SBRT for patients who were conventionally considered SBRT non-eligible. Given the large, non-convex solution space, PSO represents an attractive, parallelizable tool to
Force Analysis and Optimization of Digging Shovel of Cassava Harvester%木薯收获机挖掘铲的受力分析与优化
Institute of Scientific and Technical Information of China (English)
李宝灵; 何兵; 刘旭红; 宋世柳; 陈定军
2016-01-01
Load condition of a digging shovel directly affects its performance and working life , and what mainly impacts on a digging shovel ' s load condition is the angle of shovel surface .In this paper , we conduct a force analysis on the process of reaching the digging depth and digging cassavas , then optimize the digging angle using ANSYS .In this way , we obtain the best angle of both big and small shovel surface in minimal load condition at the specific digging depth .This work provides the theoretical base for structural optimum design of digging shovels .%挖掘铲的受力情况直接影响挖掘机的工作效果及寿命,挖掘铲面角度是影响挖掘铲受力的主要因素.为此,对木薯收获机挖掘铲在达到挖掘深度进行挖掘木薯的过程进行受力分析,并利用 ANSYS 软件对铲面角度进行优化,得出在一定的挖掘深度下受力最小的大铲面和小铲面的最佳角度,为挖掘铲的结构优化设计提供理论依据.
1976-01-01
routines whereby time and temperature during processing is c efully controlled and product quality optimized prevented a HACCP analysis by NDC personne KA...consistent processing routines whereby time and temperature during processing is carefully controlled and product quality optimized prevented a HACCP analysis... meat loaf 17 3 The effect of processing on the microflora of salisbury steak 18 4 The effect of processing on the microflora of BBQ chicken 19 5 The
DEFF Research Database (Denmark)
Jonas, Lindemann; Damkilde, Lars
2008-01-01
Design of structures such as bridges, wind turbine wings or mechanical components is a very challenging task and involves both finding the structural layout and analysis of the bearing capacity of the structure. The analysis part is almost always solved by Finite Elements and involves defining a ...
Son, Jino; Vavra, Janna; Li, Yusong; Seymour, Megan; Forbes, Valery
2015-04-01
The preparation of a stable nanoparticle stock suspension is the first step in nanotoxicological studies, but how different preparation methods influence the physicochemical properties of nanoparticles in a solution, even in Milli-Q water, is often under-appreciated. In this study, a systematic approach using a central composite design (CCD) was employed to investigate the effects of sonication time and suspension concentration on the physicochemical properties (i.e. hydrodynamic diameter, zeta potential and ion dissolution) of silver (Ag) and copper oxide (CuO) nanoparticles (NPs) and to identify optimal conditions for suspension preparation in Milli-Q water; defined as giving the smallest particle sizes, highest suspension stability and lowest ion dissolution. Indeed, all the physicochemical properties of AgNPs and CuONPs varied dramatically depending on how the stock suspensions were prepared and differed profoundly between nanoparticle types, indicating the importance of suspension preparation. Moreover, the physicochemical properties of AgNPs and CuONPs, at least in simple media (Milli-Q water), behaved in predictable ways as a function of sonication time and suspension concentration, confirming the validity of our models. Overall, the approach allows systematic assessment of the influence of various factors on key properties of nanoparticle suspensions, which will facilitate optimization of the preparation of nanoparticle stock suspensions and improve the reproducibility of nanotoxicological results. We recommend that further attention be given to details of stock suspension preparation before conducting nanotoxicological studies as these can have an important influence on the behavior and subsequent toxicity of nanoparticles.
Talat, Mahe; Singh, Ashwani Kumar; Srivastava, O N
2011-08-01
In the present study, enzyme urease has been immobilized on amine-functionalized gold nanoparticles (AuNPs). AuNPs were synthesized using natural precursor, i.e., clove extract and amine functionalized through 0.004 M L: -cysteine. Enzyme (urease) was extracted and purified from the vegetable waste, i.e., seeds of pumpkin to apparent homogeneity (sp. activity 353 U/mg protein). FTIR spectroscopy and transmission electron microscopy was used to characterize the immobilized enzyme. The immobilized enzyme exhibited enhanced activity as compared with the enzyme in the solution, especially, at lower enzyme concentration. Based on the evaluation of activity assay of the immobilized enzyme, it was found that the immobilized enzyme was quite stable for about a month and could successfully be used even after eight cycles having enzyme activity of about 47%. In addition to this central composite design (CCD) with the help of MINITAB version 15 Software was utilized to optimize the process variables viz., pH and temperature affecting the enzyme activity upon immobilization on AuNPs. The results predicted by the design were found in good agreement (R2 = 96.38%) with the experimental results indicating the applicability of proposed model. The multiple regression analysis and ANOVA showed the individual and cumulative effect of pH and temperature on enzyme activity indicating that the activity increased with the increase of pH up to 7.5 and temperature 75 °C. The effects of each variables represented by main effect plot, 3D surface plot, isoresponse contour plot and optimized plot were helpful in predicting results by performing a limited set of experiments.
Lu, Hongwei; Du, Peng; Chen, Yizhong; He, Li
2016-06-01
This study presents a credibility-based chance-constrained optimization model for integrated agricultural irrigation and water resources management. The model not only deals with parameter uncertainty represented as fuzzy sets, but also provides a credibility level which indicates the confidence level of the generated optimal management strategies. The model is used on a real-world case study in South Central China. Results from the case study reveal that: (1) a reduction in credibility level would result in an increasing planting area of watermelon, but impaired the planting acreage of high-quality rice and silk; (2) groundwater allocation would be prioritized for reducing surface water utilization cost; (3) the actual phosphorus and nitrogen emissions reached their limit values in most of the zones over the planning horizon (i.e., phosphorus and nitrogen emissions reaching 969 tonnes and 3814 tonnes under λ = 1.00, respectively; phosphorus and nitrogen emissions reaching 972 tonnes and 3891 tonnes under λ = 0.70, respectively). When the credibility level reduces from 1.00 to 0.70, system benefit would rise by 32.60% and groundwater consumption would be reduced by 79.51%. However, the pollutant discharge would not increase as expected, which would be reduced by 40.14% on the contrary. If system benefit is not of major concern, an aggressive strategy is suggested by selecting a rather low credibility level (say, 0.70). This strategy is suggested for guaranteeing protection of local groundwater resources and mitigation of local environmental deterioration by sacrificing part of system benefit.
Kamankesh, Marzieh; Mohammadi, Abdorreza; Tehrani, Zohreh Modarres; Ferdowsi, Roohallah; Hosseini, Hedayat
2013-05-15
A new method based on dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography (HPLC) for determination of benzoate and sorbate salts in yogurt drinks was developed. The effective parameters in DLLME process, including volume of extraction and disperser solvents, pH and salt effect, were optimized using response surface methodology (RSM) based on central composite design. The yogurt drink samples were extracted using NaOH and Carrez solutions (potassium hexaferrocyanide and zinc acetate) were used for sedimentation of proteins. For DLLME, a mixture of extraction solvent (1-octanol) and disperser solvent (ethanol) was rapidly injected into the sample solution by syringe and cloudy solution is formed. Subsequently, the upper 1-octanol layer was analyzed by HPLC. The detection limits for benzoate and sorbate were 0.06 ng mL(-1) and 0.15 ng mL(-1), respectively. The relative standard deviations (RSD) for seven analyses were 4.96% for benzoate and 4.58% for sorbate. The proposed method demonstrated good linearity and high enrichment factor. A clean separation and good chromatogram is readily achieved without the presence of matrix interference. A comparison of this method with previous methods demonstrated that the proposed method is an accurate, rapid and reliable sample-pretreatment method that gives very good enrichment factors and detection limits for extracting and determining sorbate and benzoate in yogurt drink samples.
Subramanian, Venkatesan; Nagappan, Kannappan; Sandeep Mannemala, Sai
2015-01-01
A sensitive, accurate, precise and rapid HPLC-PDA method was developed and validated for the simultaneous determination of torasemide and spironolactone in human plasma using Design of experiments. Central composite design was used to optimize the method using content of acetonitrile, concentration of buffer and pH of mobile phase as independent variables, while the retention factor of spironolactone, resolution between torasemide and phenobarbitone; and retention time of phenobarbitone were chosen as dependent variables. The chromatographic separation was achieved on Phenomenex C(18) column and the mobile phase comprising 20 mM potassium dihydrogen ortho phosphate buffer (pH-3.2) and acetonitrile in 82.5:17.5 v/v pumped at a flow rate of 1.0 mL min(-1). The method was validated according to USFDA guidelines in terms of selectivity, linearity, accuracy, precision, recovery and stability. The limit of quantitation values were 80 and 50 ng mL(-1) for torasemide and spironolactone respectively. Furthermore, the sensitivity and simplicity of the method suggests the validity of method for routine clinical studies.
Ara, Katayoun Mahdavi; Jowkarderis, Mina; Raofie, Farhad
2015-07-01
Essential oils and fatty acids of Descurainia sophia L. seed were obtained by supercritical CO2 extraction and steam distillation methods. The effect of different parameters such as pressure, temperature, modifier volume, dynamic and static extraction timeon the extraction yield were optimized using a central composite design after a 2 (n-1) fractional factorial design. The results showed that under the pressure of 355 bar, temperature of 65 °C, methanol volume of 150 μL, dynamic and static extraction times of 35 and 10 min, respectively, the major components were methyl linoleate (18.2 %), camphor (12.32 %), cis-thujone (11.3 %) and trans-caryophyllene (9.17 %). The results indicated that by using the proper conditions, the supercritical fluid extraction is more selective than the steam distillation method. Extraction yields based on supercritical fluid extraction varied in the range of 0.68 to 17.1 % (w/w), and the extraction yield based on the steam distillation was 0.25 % (v/w).
Directory of Open Access Journals (Sweden)
Sevinç Karadağ
2016-04-01
Full Text Available Rapid determination of sodium (Na ions in soil samples using ion selective electrodes (ISE was investigated in this study. The compatibility of ISEs with soil extraction solution is a challenging subject as various effects such as pH, ionic strength and other interferences have to be considered as well as efficiency of the extraction solution. Because almost every type of sodium salt is soluble in water, and the pH of water is suitable for ISE studies, it was chosen as the soil extractant. Firstly, the extraction parameters were optimized by using a central composite design (CCD, secondly thirty agricultural soil samples were extracted with water and the extracts were measured by Na-ISE in a previously developed flow system. The results were compared with ion chromatography (IC as the reference method, and the regression analysis between IC and ISE results yielded a high correlation (R² = 0.9408. It was concluded that, ion selective electrodes can be used with water as an extraction solution for rapid determination of sodium in soil samples.
Aghaeinejad-Meybodi, Abbas; Ebadi, Amanollah; Shafiei, Sirous; Khataee, Alireza; Rostampour, Mohammad
2015-01-01
The main objective of this work is the modelling and optimization of antidepressant drug fluoxetine degradation in aqueous solution by ozone/H2O2 process using central composite design. The operational parameters were ozone concentration, initial hydrogen peroxide concentration, reaction time and initial fluoxetine concentration. A good agreement between the predicted values of fluoxetine removal and experimental results were observed (R2=0.976 and Adj-R2=0.955). Pareto analysis indicated that all selected factors and some interactions were effective on the removal efficiency. It was found that the reaction time is the most effective parameter in the ozone/H2O2 process. The maximum removal efficiency (86.14%) was achieved at ozone concentration of 30 mg L(-1), initial H2O2 concentration of 0.02 mM, reaction time of 20 min and initial fluoxetine concentration of 50 mg L(-1) as the optimum conditions.
2010-06-01
March 2006, viii. 44 AFDD 2-6, Air Mobility Operations, viii. 45 Advanced Study of Air Mobility ( ASAM ) Class XV USCENTCOM Orientation Student Guide...Associated Terms, 227. 53 JP 1-02, DoD Dictionary of Military and Associated Terms, 364. 54 ASAM Class XV USCENTCOM Orientation Student Guide, 17...mission forces throughout the theater. 94 AFDD 2-6, Air Mobility Operations, 23. 95 ASAM
Performance parameter optimization and experiment of forced-vibration subsoiler%受迫振动深松机性能参数优化与试验
Institute of Scientific and Technical Information of China (English)
李霞; 张东兴; 王维新; 崔涛; 汤明军
2015-01-01
was forward velocity > vibration frequency > vibration angle, and the total power values firstly increased and then decreased with the increasing of vibration frequency while the total power values firstly decreased and then increased with the increasing of vibration angle. The sequence of factors in affecting the torque was vibration frequency > forward velocity > vibration angle, and the torque values firstly increased and then decreased with the increasing of forward velocity while the torque values consistently increased with the increasing of vibration frequency. The optimal combination of the performance parameters was the forward velocity of 2 km/h, the vibration frequency of 10Hz and the vibration angle of 12°. For further validating the rationality of optimal combination of parameters, the test on working performance of the forced-vibration subsoiler was carried out in the experimental field, and soil properties (bulk density and water content), soil bulkiness, soil disturbance coefficient and traction resistance were selected as the evaluation indicators to compare with non-vibration subsoiler. The results showed that the bulk density of all soil layer decreased after forced-vibration sub-soiling and that at 0-15 cm soil layer decreased by 21.74%. At the same time, the water content at 15-25 cm increased by 16.02%. The variation coefficient and stability coefficient of sub-soiling depth, which were the indicators to the change quantity and degree, were 7.37% and 92.63% respectively. Meanwhile, the variation coefficient and stability coefficient of the depth reached the requirements of the Ministry of Agriculture, and the land surface was smooth and flat after sub-soiling. Moreover, soil disturbance coefficient was 57.11% after subsoiling and soil bulkiness was 36.96%. Both soil bulkiness and disturbance coefficient reached the requirements of the test indicators. In addition, the traction resistance was reduced by 9.09% compared with non-vibrating subsoiler
Energy Technology Data Exchange (ETDEWEB)
Durfee, Justin David; Frazier, Christopher Rawls; Bandlow, Alisa; Jones, Katherine A
2016-05-01
This document describes the final software design of the Contingency Contractor Optimization Tool - Prototype. Its purpose is to provide the overall architecture of the software and the logic behind this architecture. Documentation for the individual classes is provided in the application Javadoc. The Contingency Contractor Optimization project is intended to address Department of Defense mandates by delivering a centralized strategic planning tool that allows senior decision makers to quickly and accurately assess the impacts, risks, and mitigation strategies associated with utilizing contract support. The Contingency Contractor Optimization Tool - Prototype was developed in Phase 3 of the OSD ATL Contingency Contractor Optimization project to support strategic planning for contingency contractors. The planning tool uses a model to optimize the Total Force mix by minimizing the combined total costs for selected mission scenarios. The model optimizes the match of personnel types (military, DoD civilian, and contractors) and capabilities to meet mission requirements as effectively as possible, based on risk, cost, and other requirements.
Zeng, Cheng; Jiang, Wen; Tan, Meie; Yang, Xiaoyi; He, Chenghui; Huang, Wei; Xing, Jianguo
2016-03-31
Tilianin is attracting considerable attention because of its antihypertensive, anti-atherogenic and anticonvulsive efficacy. However, tilianin has poor oral bioavailability. Thus, to improve the oral bioavailability of tilianin, composite phospholipid liposomes were adopted in this work as a novel nanoformulation. The aim was to develop and formulate tilianin composite phospholipid liposomes (TCPLs) through ethanol injection and to apply the response surface-central composite design to optimize the tilianin composite phospholipid liposome formulation. The independent variables were the amount of phospholipids (X1), amount of cholesterol (X2) and weight ratio of phospholipid to drug (X3); the depended variables were particle size (Y1) and encapsulation efficiency (EE) (Y2) of TCPLs. Results indicated that the optimum preparation conditions were as follows: phospholipid amount, 500 mg, cholesterol amount, 50mg and phospholipid/drug ratio, 25. These variables were also the major contributing variables for particle size (101.4 ± 6.1 nm), higher EE (90.28% ± 1.36%), zeta potential (-18.3 ± 2.6 mV) and PDI (0.122 ± 0.027). Subsequently, differential scanning calorimetry techniques were used to investigate the molecular interaction in TCPLs, and the in vitro drug release of tilianin and TCPLs was investigated by the second method of dissolution in the Chinese Pharmacopoeia (Edition 2015). Furthermore, pharmacokinetics in Sprague Dawley rats was evaluated using a rat jugular vein intubation tube. Results demonstrated that the Cmax of TCPLs became 5.7 times higher than that of tilianin solution and that the area under the curve of TCPLs became about 4.6-fold higher than that of tilianin solution. Overall, our results suggested that the prepared tilianin composite phospholipid liposome formulations could be used to improve the bioavailability of tilianin after oral administration.
Energy Technology Data Exchange (ETDEWEB)
Mohamed, Alina Rahayu; Hamzah, Zainab; Daud, Mohamed Zulkali Mohamed [School of Bioprocess Engineering, Jejawi Complex of Academics (3), UniMAP, 02600 Arau Perlis (Malaysia)
2014-07-10
The production of crude palm oil from the processing of palm fresh fruit bunches in the palm oil mills in Malaysia hs resulted in a huge quantity of empty fruit bunch (EFB) accumulated. The EFB was used as a feedstock in the pyrolysis process using a fixed-bed reactor in the present study. The optimization of process parameters such as pyrolysis temperature (factor A), biomass particle size (factor B) and holding time (factor C) were investigated through Central Composite Design (CCD) using Stat-Ease Design Expert software version 7 with bio-oil yield considered as the response. Twenty experimental runs were conducted. The results were completely analyzed by Analysis of Variance (ANOVA). The model was statistically significant. All factors studied were significant with p-values < 0.05. The pyrolysis temperature (factor A) was considered as the most significant parameter because its F-value of 116.29 was the highest. The value of R{sup 2} was 0.9564 which indicated that the selected factors and its levels showed high correlation to the production of bio-oil from EFB pyrolysis process. A quadratic model equation was developed and employed to predict the highest theoretical bio-oil yield. The maximum bio-oil yield of 46.2 % was achieved at pyrolysis temperature of 442.15 °C using the EFB particle size of 866 μm which corresponded to the EFB particle size in the range of 710–1000 μm and holding time of 483 seconds.
Mohamed, Alina Rahayu; Hamzah, Zainab; Daud, Mohamed Zulkali Mohamed
2014-07-01
The production of crude palm oil from the processing of palm fresh fruit bunches in the palm oil mills in Malaysia hs resulted in a huge quantity of empty fruit bunch (EFB) accumulated. The EFB was used as a feedstock in the pyrolysis process using a fixed-bed reactor in the present study. The optimization of process parameters such as pyrolysis temperature (factor A), biomass particle size (factor B) and holding time (factor C) were investigated through Central Composite Design (CCD) using Stat-Ease Design Expert software version 7 with bio-oil yield considered as the response. Twenty experimental runs were conducted. The results were completely analyzed by Analysis of Variance (ANOVA). The model was statistically significant. All factors studied were significant with p-values < 0.05. The pyrolysis temperature (factor A) was considered as the most significant parameter because its F-value of 116.29 was the highest. The value of R2 was 0.9564 which indicated that the selected factors and its levels showed high correlation to the production of bio-oil from EFB pyrolysis process. A quadratic model equation was developed and employed to predict the highest theoretical bio-oil yield. The maximum bio-oil yield of 46.2 % was achieved at pyrolysis temperature of 442.15 °C using the EFB particle size of 866 μm which corresponded to the EFB particle size in the range of 710-1000 μm and holding time of 483 seconds.
A New Force-Matched Reactive Force Field for Bulk Water Under Extreme Thermodynamic Conditions
Fried, Laurence; Koziol, Lucas
2015-06-01
A many-body classical force field is presented for water under dissociative thermodynamic conditions. The force field is optimized by force-matching to ab initio molecular dynamics (AIMD) simulations calculated with Density Functional Theory (DFT). The force field contains short-ranged central and many-body over-coordination terms, and long-range Ewald electrostatics. It is optimized and tested on water at density 1.5 g/mL and 2000 K, which is approximately 10% dissociated according to DFT. Molecular dynamics simulations closely reproduce DFT radial distribution functions, as well as the distribution of wat and dissociation products. The calculated atomic self-diffusion constants appear about 50% lower than in DFT, although precise comparison is impossible due to the short timescale accessible to AIMD (about 20 ps). The force field is also compared to ReaxFF using the CHO parameter set of Chenowith et al. ReaxFF structural and dynamical properties are in overall fair agreement with DFT, although ReaxFF water is not dissociative at these conditions. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Kall, Peter
1998-01-01
Optimization problems arising in practice usually contain several random parameters. Hence, in order to obtain optimal solutions being robust with respect to random parameter variations, the mostly available statistical information about the random parameters should be considered already at the planning phase. The original problem with random parameters must be replaced by an appropriate deterministic substitute problem, and efficient numerical solution or approximation techniques have to be developed for those problems. This proceedings volume contains a selection of papers on modelling techniques, approximation methods, numerical solution procedures for stochastic optimization problems and applications to the reliability-based optimization of concrete technical or economic systems.
Trajectory optimization of multiple quad-rotor UAVs in collaborative assembling task
Institute of Scientific and Technical Information of China (English)
Chen Yongbo; Yu Jianqiao; Mei Yuesong; Zhang Siyu; Ai Xiaolin; Jia Zhenyue
2016-01-01
A hierarchic optimization strategy based on the offline path planning process and online trajectory planning process is presented to solve the trajectory optimization problem of multiple quad-rotor unmanned aerial vehicles in the collaborative assembling task. Firstly, the path planning process is solved by a novel parallel intelligent optimization algorithm, the central force optimization-genetic algorithm (CFO-GA), which combines the central force optimization (CFO) algorithm with the genetic algorithm (GA). Because of the immaturity of the CFO, the convergence analysis of the CFO is completed by the stability theory of the linear time-variant discrete-time sys-tems. The results show that the parallel CFO-GA algorithm converges faster than the parallel CFO and the central force optimization-sequential quadratic programming (CFO-SQP) algorithm. Then, the trajectory planning problem is established based on the path planning results. In order to limit the range of the attitude angle and guarantee the flight stability, the optimized object is changed from the ordinary six-degree-of-freedom rigid-body dynamic model to the dynamic model with an inner-loop attitude controller. The results show that the trajectory planning process can be solved by the mature SQP algorithm easily. Finally, the discussion and analysis of the real-time per-formance of the hierarchic optimization strategy are presented around the group number of the waypoints and the equal interval time.
Trajectory optimization of multiple quad-rotor UAVs in collaborative assembling task
Directory of Open Access Journals (Sweden)
Chen Yongbo
2016-02-01
Full Text Available A hierarchic optimization strategy based on the offline path planning process and online trajectory planning process is presented to solve the trajectory optimization problem of multiple quad-rotor unmanned aerial vehicles in the collaborative assembling task. Firstly, the path planning process is solved by a novel parallel intelligent optimization algorithm, the central force optimization-genetic algorithm (CFO-GA, which combines the central force optimization (CFO algorithm with the genetic algorithm (GA. Because of the immaturity of the CFO, the convergence analysis of the CFO is completed by the stability theory of the linear time-variant discrete-time systems. The results show that the parallel CFO-GA algorithm converges faster than the parallel CFO and the central force optimization-sequential quadratic programming (CFO-SQP algorithm. Then, the trajectory planning problem is established based on the path planning results. In order to limit the range of the attitude angle and guarantee the flight stability, the optimized object is changed from the ordinary six-degree-of-freedom rigid-body dynamic model to the dynamic model with an inner-loop attitude controller. The results show that the trajectory planning process can be solved by the mature SQP algorithm easily. Finally, the discussion and analysis of the real-time performance of the hierarchic optimization strategy are presented around the group number of the waypoints and the equal interval time.
DEFF Research Database (Denmark)
Bendsøe, Martin P.; Sigmund, Ole
2007-01-01
Taking as a starting point a design case for a compliant mechanism (a force inverter), the fundamental elements of topology optimization are described. The basis for the developments is a FEM format for this design problem and emphasis is given to the parameterization of design as a raster image...
Institute of Scientific and Technical Information of China (English)
朱琴跃; 王景熙; 申朝旭; 谭喜堂
2015-01-01
For the problem that the electro-pneumatic braking force distribution strategy of existing subway trains hasn't fully considered the different demands of braking force applied to different train axles, the optimization control algorithm of the further distribution of braking force on different train axles is presented. On analysis of electro-pneumatic cooperative control strategy of electric brake priority for the basic control unit making up of 2 motor cars and 1 trailer car in the certain Beijing subway train, the optimization algorithm based on the axle load transfer is put forward, which proposes that the braking force is applied proportionally to different train axles in terms of the pressures withstood by their corresponding wheel pairs. By using Matlab/Simulink software to model and simulate above algorithm, the braking force distribution and changes under different braking conditions are analyzed. The results show that the braking force further distribution optimization strategy which is based on the axle load transfer helps to improve the anti-slip property and stable braking effect. And the expected result has been achieved.%针对现有地铁列车在电-空制动力分配控制策略中没有充分考虑各轴应施加制动力存在差异的问题,对制动力再分配优化控制算法进行了研究.在对电制动优先的电-空制动力协调分配算法进行分析的基础上,以北京某地铁列车中2动1拖基本制动单元为研究对象,基于轴重转移原则,提出了根据各轮对所承受压力的大小按比例再分配空气制动力的优化控制算法,并通过Matlab/Simulink软件对地铁列车处于不同制动工况下制动力的再分配情况进行了仿真和分析.仿真结果表明,基于轴重转移的各轴空气制动力再分配优化控制策略有助于改善列车防滑性能、提高列车平稳制动的效果,达到了预期目标.
Institute of Scientific and Technical Information of China (English)
张耀庭; 颜燕祥; 张正哲; 李艳芳; 张敏
2014-01-01
With the development of the large-span bridge engineering, the affirmance of the wire rope cable forces of the connection between the bridge superstructure and piers ( Abutment) has become a key technical problem in bridge design and construction process. The design of cable force is directly related to safety issues and the normal use in the construction and operational stage. Combined with the construction of a Bridge,the article presents the principle of linear programming to optimize cable force. The optimal method of cable force uses the cable dosage minimum as an objective function and the pre-tension force as optimal variables, and then uses the stress in key sections and the deflection in end of cantilever as constraint conditions. With the help of ANSYS software and MATLAB tools,the optimization of construction ( temporary) buckle cable tension of stage of the structure of linear work is achieved. Compared with the existing cable force methods, the method proposed in this paper to determine cable force can reduce the number of tune cable construction process and improve the accuracy of the design of cable force. For similar projects, it provides a new way of thinking to determine the steel cables of the relative optimum tensile force.%随着斜拉桥等大跨度桥梁工程的发展，桥梁上部结构与桥墩(台)之间连接的钢索索力的确定已成为桥梁设计与施工过程中的关键技术问题，索力取值合理与否直接关系到结构施工及运营阶段的安全与正常使用问题。本文结合某特大桥的施工，将线性规划原理引入到该桥的施工索力优化当中，以扣索用量最少为目标函数，以拉索索力大小为控制变量，以关键截面应力和悬臂端点挠度为约束条件；借助ANSYS软件和MATLAB工具，实现了结构线性工作阶段的施工(临时)扣索索力的优选分析。与已有的索力确定方法相比，本文提出的确定索力方法可减少施工过程
Stark, Austin C; Andrews, Casey T; Elcock, Adrian H
2013-09-10
Coarse-grained (CG) simulation methods are now widely used to model the structure and dynamics of large biomolecular systems. One important issue for using such methods - especially with regard to using them to model, for example, intracellular environments - is to demonstrate that they can reproduce experimental data on the thermodynamics of protein-protein interactions in aqueous solutions. To examine this issue, we describe here simulations performed using the popular coarse-grained MARTINI force field, aimed at computing the thermodynamics of lysozyme and chymotrypsinogen self-interactions in aqueous solution. Using molecular dynamics simulations to compute potentials of mean force between a pair of protein molecules, we show that the original parameterization of the MARTINI force field is likely to significantly overestimate the strength of protein-protein interactions to the extent that the computed osmotic second virial coefficients are orders of magnitude more negative than experimental estimates. We then show that a simple down-scaling of the van der Waals parameters that describe the interactions between protein pseudo-atoms can bring the simulated thermodynamics into much closer agreement with experiment. Overall, the work shows that it is feasible to test explicit-solvent CG force fields directly against thermodynamic data for proteins in aqueous solutions, and highlights the potential usefulness of osmotic second virial coefficient measurements for fully parameterizing such force fields.
Are Near Earth Objects the Key to Optimization Theory?
Formato, Richard A
2009-01-01
This note suggests that near earth objects and Central Force Optimization have something in common, that NEO theory may hold the key to solving some vexing problems in deterministic optimization: local trapping and proof of convergence. CFO analogizes Newton's laws to locate the global maxima of a function. The NEO-CFO nexus is the striking similarity between CFO's Davg and an NEO's Delta-V curves. Both exhibit oscillatory plateau-like regions connected by jumps, suggesting that CFO's metaphorical "gravity" indeed behaves like real gravity, thereby connecting NEOs and CFO and being the basis for speculating that NEO theory may address difficult issues in optimization.
Energy Technology Data Exchange (ETDEWEB)
1981-01-01
Appropriate cost and performance models and computer codes have been developed to carry out the collector field optimization, as well as additional computer codes to define the actual heliostat locations in the optimized field and to compute in detail the performance to be expected of the defined field. The range of capabilities of the available optimization and performance codes is described. The role of the optimization code in the definition of the pilot plant is specified, and a complete description of the optimization process itself is given. The detailed cost model used by the optimizer for the commercial system optimization is presented in the form of equations relating the cost element to each of the factors that determine it. The design basis for the commercial system is presented together with the rationale for its selection. The development of the individual heliostat performance code is presented. Use of the individual heliostat code in a completed study of receiver panel power under sunrise startup conditions is described. The procedure whereby performance and heliostat spacing data from the representative commercial-scale system are converted into coefficients of use in the layout processor is described, and the actual procedure used in the layout processor is described. Numerous special studies in support of the pilot plant design are described. (LEW)
Hu, Hao; Lu, Zhenyu; Parks, Jerry M.; Burger, Steven K.; Yang, Weitao
2008-01-01
To accurately determine the reaction path and its energetics for enzymatic and solution-phase reactions, we present a sequential sampling and optimization approach that greatly enhances the efficiency of the ab initio quantum mechanics/molecular mechanics minimum free-energy path (QM/MM-MFEP) method. In the QM/MM-MFEP method, the thermodynamics of a complex reaction system is described by the potential of mean force (PMF) surface of the quantum mechanical (QM) subsystem with a small number of degrees of freedom, somewhat like describing a reaction process in the gas phase. The main computational cost of the QM/MM-MFEP method comes from the statistical sampling of conformations of the molecular mechanical (MM) subsystem required for the calculation of the QM PMF and its gradient. In our new sequential sampling and optimization approach, we aim to reduce the amount of MM sampling while still retaining the accuracy of the results by first carrying out MM phase-space sampling and then optimizing the QM subsystem in the fixed-size ensemble of MM conformations. The resulting QM optimized structures are then used to obtain more accurate sampling of the MM subsystem. This process of sequential MM sampling and QM optimization is iterated until convergence. The use of a fixed-size, finite MM conformational ensemble enables the precise evaluation of the QM potential of mean force and its gradient within the ensemble, thus circumventing the challenges associated with statistical averaging and significantly speeding up the convergence of the optimization process. To further improve the accuracy of the QM/MM-MFEP method, the reaction path potential method developed by Lu and Yang [Z. Lu and W. Yang, J. Chem. Phys. 121, 89 (2004)] is employed to describe the QM/MM electrostatic interactions in an approximate yet accurate way with a computational cost that is comparable to classical MM simulations. The new method was successfully applied to two example reaction processes, the
Jelica, Stjepan; Seper, Vesna; Davidović, Erna; Bujisić, Gordana
2011-01-01
Nonspecific medical gymnastic therapy may help patients after stroke achieve certain results in terms of efficiency but not in terms of quality of movement. The goal of treatment by Bobath concept is development of movement (effectiveness) and optimization of movement (efficiency). This article presents the case of a 62-year old patient who had experienced a stroke and has difficulties with standing up activities. It underscores the importance of not only recovery of function but also optimization of the function in such patients.
Ghosal, Partha S; Gupta, Ashok K; Sulaiman, Ayoob
2016-01-01
Response surface methodology was applied for the first time in the optimization of the preparation of layered double hydroxide (LDH) for defluoridation. The influence of three vital process parameters (viz. pH, molar ratio and calcination temperature) in the synthesis of the adsorbent 'Calcined Ca‒Al (NO3) LDH' was thoroughly examined to maximize its fluoride scavenging potential. The process parameters were optimized using the 3(3) factorial, face centered central composite and Box-Behnken designs and a comparative assessment of the methods was conducted. The maximum fluoride removal efficiency was achieved at a calcination temperature of approximately 500ºC; however, the efficiency decreased with increasing pH and molar ratio. The outcome of the comparative assessment clearly delineates the case specific nature of the models. A better predictability over the entire experimental domain was obtained with the 3(3) factorial method, whereas the Box-Behnken design was found to be the most efficient model with lesser number of experimental runs. The desirability function technique was performed for optimizing the response, wherein face centered central composite design exhibited a maximum desirability. The calcined Ca‒Al (NO3) LDH, synthesized under the optimum conditions, demonstrated the removal efficiencies of 95% and 99% for the doses of 3 g L(-1) and 5 g L(-1), respectively.
2008-10-17
Citizen Security held in July 2008 indicated that Guatemala now has the second highest murder rate in Central America (roughly 45 per 100,000 people...training regional security forces.48 In recent years, the U.S. Southern Command has taken a leading role in discussing the problem of citizen security in...the results CRS-19 51 “Memo: The Merida Initiative and Citizen Security in Mexico and Central America,” Washington Office on Latin America, March 2008
Chung, Sung; Kim, Hee Jeong; Kim, Hyun Ju; Choi, Sun Hye; Cho, Jin Hee; Cho, Yun Ha; Kim, Dong-Hoon; Shin, Kyung Ho
2014-10-01
Dynorphin in the nucleus accumbens shell plays an important role in antidepressant-like effect in the forced swimming test (FST), but it is unclear whether desipramine and citalopram treatments alter prodynorphin levels in other brain areas. To explore this possibility, we injected mice with desipramine and citalopram 0.5, 19, and 23 h after a 15-min pretest swim and observed changes in prodynorphin expression before the test swim, which was conducted 24 h after the pretest swim. The pretest swim increased prodynorphin immunoreactivity in the dorsal bed nucleus of the stria terminalis (dBNST) and lateral division of the central nucleus of the amygdala (CeL). This increase in prodynorphin immunoreactivity in the dBNST and CeL was blocked by desipramine and citalopram treatments. Similar changes in prodynorphin mRNA levels were observed in the dBNST and CeL, but these changes did not reach significance. To understand the underlying mechanism, we assessed changes in phosphorylated CREB at Ser(133) (pCREB) immunoreactivity in the dBNST and central nucleus of the amygdala (CeA). Treatment with citalopram but not desipramine after the pretest swim significantly increased pCREB immunoreactivity only in the dBNST. These results suggest that regulation of prodynorphin in the dBNST and CeL before the test swim may be involved in the antidepressant-like effect of desipramine and citalopram in the FST and suggest that changes in pCREB immunoreactivity in these areas may not play an important role in the regulation of prodynorphin in the dBNST and CeA.
Institute of Scientific and Technical Information of China (English)
田志定; 李刚; 刘春; 徐建伟
2011-01-01
对某型综合电力推进舰船中央冷却系统及其相关控制技术作了综合分析,提出了系统自动控制优化设计的思路。控制装置经样机试制和实船使用,为中央冷却系统的可靠性运行提供保障。%This paper gives an overall analysis on the central cooling system and its control technologies of an integrated electric propulsion vessel; and proposes some ideas on design optimization of the automatic control system. Model machine tests as well as full scale trial prove that this control unit can guarantee the safe operation of the central cooling system.
Energy Technology Data Exchange (ETDEWEB)
Lapa, Nelbia da Silva
2005-10-15
The main purpose of this work is the definition of operational conditions for the steam and power conservation of Pressurized Water Reactor (PWR) plant in order to increase its system thermal efficiency without changing any component, based on the optimization of operational parameters of the plant. The thermal efficiency is calculated by a thermal balance program, based on conservation equations for homogeneous modeling. The circuit coefficients are estimated by an optimization tool, allowing a more realistic thermal balance for the plans under analysis, as well as others parameters necessary to some component models. With the operational parameter optimization, it is possible to get a level of thermal efficiency that increase capital gain, due to a better relationship between the electricity production and the amount of fuel used, without any need to change components plant. (author)
Cochran, Susan A.; Gibbs, Ann E.; White, Darla J.
2014-01-01
Nearshore areas off of west-central Maui, Hawai‘i, once dominated by abundant coral coverage, now are characterized by an increased abundance of turf algae and macroalgae. In an effort to improve the health and resilience of the coral reef system, the Kahekili Herbivore Fisheries Management Area was established by the State of Hawai‘i, and the U.S. Coral Reef Task Force selected the Kā‘anapali region as a priority study area. To support these efforts, the U.S. Geological survey mapped nearly 5 km2 of sea floor from the shoreline to water depths of about 30 m. Unconsolidated sediment (predominantly sand) constitutes 65 percent of the sea floor in the mapped area. Reef and other hardbottom potentially available for coral recruitments constitutes 35 percent of the mapped area. Of this potentially available hardbottom, only 51 percent is covered with a minimum of 10 percent coral, and most is found between 5 and 10 m water depth.
基于地面反力最优规划的双足机器人姿态控制%Attitude Control of Biped Robot Based on Optimal Reactive Force Distribution
Institute of Scientific and Technical Information of China (English)
田海英; 任志玲
2001-01-01
提出了一种基于地面反力最优规划的双足步行机器人上体姿态控制算法，以实现上体轨迹准确跟踪及为分级递阶控制结构中的地面反力/位混合控制提供参考输入。由于上体只安装了加速度器并未安装陀螺仪，文中采用线性观测器来重构沿偏转轴和俯仰轴的偏转速度，利用无源性理论控制器-观测器设计了保持上体姿态跟踪特性及系统为最终有界和局部指数稳定有界的地面反力期望值。%A new approach of designing attitude controller is developed based on the optimal reactive force distribution between the robot and environment. The function of the attitude controller is providing input for the force/position controller of the biped robot's Hierarchical Control System. Only get the angle of roll/pitch axis,passivity-based controller-observer is used for velocity of two axis. The idea external force input, which ensure the system of biped robot's body uniformly bounded and locally exponentially stability is get.
Institute of Scientific and Technical Information of China (English)
贾科利; 张俊华
2011-01-01
By using data derived from the 1978 MSS image and 1987,1996,2007 Landsat TM/ETM images and with the help of GIS,the land use change in arid area of central Ningxia Hui Autonomous Region was analyzed.At the same time,the driving forces of the land use change was identified by making use of the correlation analysis and principal component.The results showed that the overall trend of land use change in arid area of central Ningxia Hui Autonomous Region was in an enlargement of the areas of cultivated land,urban land,whereas sandy land area decreased 281 682 hm2,an average annual increase rate grassland area was 0.17%,and area of forest land reduced nearly 30 000 hm2 over 30 years.The land use information entropy indicating that the degree of disorder for land use system increased,and the structure of land use became complexity and diversity.It was considered that population,economic,regional socio-economic development degree,industrial structure,agricultural production,socio-input,government policy,and natural factors are the main driving forces inducing land use change in arid area of central Ningxia Hui Autonomous Region.More importantly,the principal component analysis showed that the impacts of human activity combining with some other conditions were the leading factors that induced dynamic change of the 1and use.%利用1978年MSS、1987年、1996年及2007年TM遥感影像,借助遥感和GIS技术及相关分析、主成分分析方法,对宁夏中部干旱带1978-2007年土地利用变化及驱动力进行了分析。结果表明：1978-2007年耕地、城镇用地面积快速增加,沙地面积减少了281 682hm2。草地以年均0.17%的速率不断增加,林地面积减少了近3万hm2。土地利用系统无序化程度增加,土地利用利用结构复杂性和多样性增大。人口、经济、产业结构、农业生产、投入、富裕程度、政策和自然因素是驱动研究区土地利用变化的主要因素,其中,人口作为社会经济活
Energy Technology Data Exchange (ETDEWEB)
Langhanki, Bernd [RAG Aktiengesellschaft, Herne (Germany). Projekt Weiterentwicklung Lean Processing; Koenig, Walter [RAG Deutsche Steinkohle AG, Herne (Germany). Bereich Bergtechnik
2010-09-15
Next to coal production, roadway drivage with a length of nearly 48 km in 2009 holds an important second rank amongst the core processes in German collieries. The requirements as to roadway installations, roadway cross section and quality of roadway support have grown constantly over the years past. In this context the complexity of the drivage procedure has increased as well. Of course such a development necessarily results in a revision of methods for efficiency increase, since the aims of process optimization are fixed: Improvement of quality, reliable scheduling and a reduction of production costs. At RAG, Lean Processing is the preferred optimization tool to meet these requirements. An overall analysis covers the optimization of process components on site, in the adjacent back area as well as the supporting maintenance and logistics processes. Transparency through key figures as well as a systematic and methodical approach, including the working staff, is the key element to eliminate waste from the processes, to further increase work safety and to meet the customer's requirements as to later usage. (orig.)
Directory of Open Access Journals (Sweden)
Khalilah Abdul Khalil
2014-01-01
Full Text Available This study was undertaken to optimize skim milk and yeast extract concentration as a cultivation medium for optimal Bifidobacteria pseudocatenulatum G4 (G4 biomass and β-galactosidase production as well as lactose and free amino nitrogen (FAN balance after cultivation period. Optimization process in this study involved four steps: screening for significant factors using 23 full factorial design, steepest ascent, optimization using FCCD-RSM, and verification. From screening steps, skim milk and yeast extract showed significant influence on the biomass production and, based on the steepest ascent step, middle points of skim milk (6% wt/vol and yeast extract (1.89% wt/vol were obtained. A polynomial regression model in FCCD-RSM revealed that both factors were found significant and the strongest influence was given by skim milk concentration. Optimum concentrations of skim milk and yeast extract for maximum biomass G4 and β-galactosidase production meanwhile low in lactose and FAN balance after cultivation period were 5.89% (wt/vol and 2.31% (wt/vol, respectively. The validation experiments showed that the predicted and experimental values are not significantly different, indicating that the FCCD-RSM model developed is sufficient to describe the cultivation process of G4 using skim-milk-based medium with the addition of yeast extract.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Dongping
2009-10-26
Lateral forced cooling can significantly increase the temporary overload capacity of a cable system, but the design of such systems requires a time-dependent 3D analysis of the nonlinear thermal behavior as the cooling water along the cable is heated up, resulting in position-dependent and time-dependent heat uptake. For this, a new calculation method was developed on the basis of an available 3D FEM software. The new method enables 3D simulation of force-cooled cables in consideration of the potential partial dryout of soil and of thermal stabilizations. The new method was first applied to a 110 kV wind power transmission cable for different configurations and grid conditions. It was found that with lateral forced cooling, the 110 kV will have a temporal 50 percent overload capacity. Further, the thermal characteristics and limiting capacity of a force-cooled 380 kV cable system were investigated. According to the results so far, laterally cooled cable systems open up new operating options, with advantages in terms of availability, economic efficiency, and flexibility. (orig.) [German] Eine laterale Zwangskuehlung kann die temporaere Ueberlastbarkeit einer Kabelanlage signifikant erhoehen. Der Entwurf solcher zwangsgekuehlter Kabelanlagen erfordert jedoch eine zeitabhaengige, dreidimensionale Analyse des nichtlinearen thermischen Verhaltens, da sich das Kuehlwasser entlang der Trasse erwaermt und sich so eine orts- und zeitabhaengige Waermeaufnahme ergibt. Zu diesem Zweck wurde auf der Basis eines vorhandenen zweidimensionalen FEM-Programms ein neues Berechnungsverfahren entwickelt, das die dreidimensionale Simulation zwangsgekuehlter Kabelanlagen unter Beruecksichtigung einer moeglicherweise auftretenden partiellen Bodenaustrocknung und von thermischen Stabilisierungen erlaubt. Mit Hilfe dieses Berechnungsverfahrens wurde zuerst eine 110-kV-Kabelanlage zur Windenergieuebertragung bei unterschiedlichen Anordnungen und unterschiedlichen Netzsituationen untersucht
Institute of Scientific and Technical Information of China (English)
单晓杭; 黄航航
2016-01-01
针对气浮悬挂装置运动过程中的气压波动和惯性力补偿问题，提出一种电磁力补偿装置，通过钕铁硼磁体产生磁场，设计了合理的磁路。应用Maxwell对该装置进行磁场仿真，通过对比及分析，优化了导磁材料的尺寸和结构，使有效行程内气隙中磁感应强度保持恒定，控制线圈回路中的电流产生需要的电磁力，补偿气压力与目标力的差值和惯性力。%Aiming at air pressure fluctuation and redundant inertia force caused by the motion of air floating suspension system, this article proposes a electromagnetic force compensation device. NdFeB magnet was used for designing a proper magnetic circuit to generate magnetic field. Maxwell was used for simulating and analyzing the magnetic circuit of this mechanism. By comparison and analysis, the structures and sizes of magnetic conductive material was optimized, which can keep the same value of magnetic induction in the air gap within the effective stroke. This system can compensate the force difference between air pressure and desired firce and inertia force by controlling the current flowing though the coils.
Occupational Outlook Quarterly, 2012
2012-01-01
The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…
Institute of Scientific and Technical Information of China (English)
周洪伟; 郝丽静; 杨勇; 张林; 杨桃; 周坤; 吴晓丹
2012-01-01
目的:优选玄参中哈巴苷和哈巴俄苷的提取工艺.方法:采用星点设计-效应面法,以哈巴苷与哈巴俄苷总提取率为指标,考察提取溶剂、液料比和提取时间对其的影响.结果:18%~32%乙醇,液料比20∶.1~26∶.1,提取30~48min时玄参总提取率最高.结论:星点设计-效应面法优化了玄参中哈巴苷与哈巴俄苷的提取工艺,预测性良好且简便可行.%Objective: To optimize the; extraction process for radix scrophnlariae by central composite design and response surface methodology. Methods: Central composite design and response surface methodology was used to optimize the extracting process. The main influential factors of extraction efficiency are ethanol concentration,solvent ratio and reflux time;. The; conditions of the extraction were evaluated by the total content of harpagide and harpagoside. Results: Analysis indicated the optimum conditions of harpagide and harpagoside are 18% -32% ethanol,20 -26 fold solvent,ultrasonic extraction 30 -48 minutes. Conclusion:It shows that the optimum process for
Directory of Open Access Journals (Sweden)
E. Ashour Warda
Full Text Available ABSTRACT Biological control strategy which can damage chitin, a vital component of pathogenic fungi and arthropods promises a safe solution for many fungal problems. And it’s more favorable than chemicals which increase health risks and environmental problems. Thus, the chitinase producers appear potential candidates of biological control of pathogenic fungi. Brevundimonus diminuta KT277492 is a new isolate that has been isolated recently from Egyptian soil. Significant factors that affecting the chitinase enzyme production were studied and optimized using Plackett-Burman and Response Surface Methodology (RSM. As a result, maximum production of chitinase enzyme was 832.87 IUL-1, this result presented about 8.767-fold increase in the enzyme production. In the last phase of the study, partially purified chitinase enzyme obtained from B. diminuta KT277492 was tested against two pathogenic fungi and the results showed good inhibitory activity against A. alternata and F. solani with IZD of 31±0.25 and 25±0.91 mm respectively. Finally, obtained results indicated the value of optimization process and the optimized chitinase enzyme could be an excellent choice in application of food and biotechnology as a biofungicide. This reflects the necessity of studying the characteristics and kinetics of the enzyme in the forthcoming study.
Institute of Scientific and Technical Information of China (English)
张润昊; 肖兆武
2015-01-01
一个城市是否有核心竞争力，最根本的是看它的文化力。襄阳文化力涵盖了“自强不息、昂扬向上”的精神原动力，“崇文重教、尊重人才”的核心智慧力，“崇尚科学、敢为人先”的强劲活力，“重商亲商、重利尚义”的城市竞争力，“注重生态、追求和谐”的可持续发展力。襄阳要建成汉江流域中心城市，要充分发挥文化力的龙头作用、纽带作用、中心作用。打造襄阳文化力，需要全面提升市民素质，打造襄阳“气质”；大力实施文化惠民工程，打造襄阳“气韵”；精心培育城市文化品牌，打造襄阳“气派”；积极推进文化传播交流，打造襄阳“气场”；勇于创新文化体制机制，打造襄阳“气魄”。%It is the cultural force that determines a city’ s core competitiveness.For Xiangyang City, the cultural force means:“unyielding and uplifting”;“respecting for knowledge, respecting for talent” ;“advocating science, daring to be the first”;“attaching importance to business, emphasizing righteousness”and “paying attention to e-cology, pursuing harmony”.To become the central city of the Han River basin, Xiangyang should give full play to the leading role of its culture.It is necessary to improve citizen’ s quality, to cultivate Xiangyang“temperament”, to implement vigorously the people-benefit engineering, to build urban cultural brand, to promote actively the cul-tural communication and to innovate culture systems.
Buhmann, Stefan Yoshi
2012-01-01
In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...
Ryter, Derek W.; Kunkel, Christopher D.; Peterson, Steven M.; Traylor, Jonathan P.
2015-08-13
A hydrogeological study including two numerical groundwater-flow models was completed for the Citizen Potawatomi Nation Tribal Jurisdictional Area of central Oklahoma. One numerical groundwater-flow model, the Citizen Potawatomi Nation model, encompassed the jurisdictional area and was based on the results of a regional-scale hydrogeological study and numerical groundwater flow model of the Central Oklahoma aquifer, which had a geographic extent that included the Citizen Potawatomi Nation Tribal Jurisdictional Area. The Citizen Potawatomi Nation numerical groundwater-flow model included alluvial aquifers not in the original model and improved calibration using automated parameter-estimation techniques. The Citizen Potawatomi Nation numerical groundwater-flow model was used to analyze the groundwater-flow system and the effects of drought on the volume of groundwater in storage and streamflow in the North Canadian River. A more detailed, local-scale inset model was constructed from the Citizen Potawatomi Nation model to estimate available groundwater resources for two Citizen Potawatomi Nation economic development zones near the North Canadian River, the geothermal supply area and the Iron Horse Industrial Park.
Institute of Scientific and Technical Information of China (English)
付中涛; 杨文玉; 张彦辉; 蔡潘
2016-01-01
针对复杂曲面恒定进给速度带来加工效率低下及表面质量差的情况,提出了基于切削力预测模型的铣削进给速度优化方法.首先,通过对刀位轨迹、曲面与刀具几何、刀/工切削接触区及动态切削厚度的分析计算,建立了多轴加工复杂曲面的切削力预测模型,从而得到了进给速度与切削力之间的映射关系.然后将给定的参考切削力与每个刀位点处的最大切削力之差的绝对值作为优化目标函数,通过Newton-Raphson迭代算法来调整原刀位点文件中的进给速度,以确保切削力的恒定以及机床系统的运行平稳.最后,以模型桨桨叶为对象,开展了相应的加工实验.实验结果表明:提出的优化方法使桨叶精加工的时间缩短了25％以上,表面残余应力和显微硬度得到增加,这对提高桨叶曲面的加工效率与改善加工表面质量具有明显的效果,从而验证了所提出的进给速度优化方法的有效性.%In terms of the low machining efficiency and bad surface quality using constant feedrate in complex surface milling,a feedrate optimization method is proposed based on cutting force model.Firstly,by the analysis and calculation of the tool path,the geometry of complex surface and tool,tool-workpiece engagement zone and uncut chip thickness,a cutting force model is derived in multi-axis maching of complex surface and the mapping relation is obtained between feedrate and cutting force.Then the objective function about the absolute value of difference between the reference cutting force and the maximum one calculated in each tool position is put forward.Then the method adopts Newton-Raphson iteration algorithm to alter the feedrate in the original tool path file,thus ensures the constant cutting forces and enhance steadiness of machining process.The experiment is carried out about model propeller,the results show that the proposed optimization method ensures the machining time of the blade
Analysis of the forces acting on beating cilia
Sangani, Ashok S.; Vidyadharan, Jyothish; Foster, Kenneth W.
2016-06-01
Detailed analysis of the forces acting on a uniform-diameter beating cilium is carried out to determine the moment generated by the inter-doublet forces acting along the length of a cilium and the results are compared with the sliding-control theory according to which the moment is a function of the interdoublet sliding. In the central part of the cilium the inter-doublet forces are found to be proportional to the inter-doublet sliding. However, in spite of the uniformity of the diameter of the cilium, the proportionality constant, known as the dynamic stiffness, is not constant along its entire length. Significant variations are observed in the regions both near the tip of the cilium and proximal to the cell body. In the tip region the magnitude of the dynamic stiffness is found to decrease. This decrease is probably due to decrease in the number density of the molecular motors in that region and in the number of doublet microtubules. The behavior in the proximal region, on the other hand, does not appear to be well described by the sliding control theory. Our analysis therefore suggests that the dynamics of ciliary beating cannot be adequately described by a simple sliding-control theory with constant dynamic stiffness. Our analysis suggests that the cilium is differentiated into a basal region optimized for the creation of a wave and a central region optimized to support a traveling wave that provides the thrust for the cell.
孔庄煤矿集中降温方案的选择与优化%Optimization of centralized cooling schemes in Kongzhuang Coal Mine
Institute of Scientific and Technical Information of China (English)
吴继忠; 刘祥来; 姚向东; 王建军
2011-01-01
According to the cross-section layout of Kongzhuang Coal Mine shaft and mine production conditions, the paper summarized and analyzed the systems of slice ice cooling, the thermo-power glycol cooling, HEMS underground centralized cooling, and vacuum ice cooling. From the effect, investment, cooling system operating stability, thermal transportation pipe installation, quality of water, discharge of heat underground, and other comprehensive consideration of the centralized cooling plan, the suitable way of cooling the mine is only the vacuum ice cooling scheme. Meanwhile, through implementation of the project, it will fill a centralized cooling technology gap in ice making technology, ice transportation pipes, ice transportation process, pressurized air cooling, underground ice melting technology, and energy-saving technology in ice making, which is a great breakthrough in our coal mines.%从孔庄煤矿井筒布置和矿井生产条件出发,先后总结、分析了片冰降温系统、热-电-乙二醇降温系统、井下低温水排热的井下集中降温系统(HEMS)和真空制冰降温系统.从集中降温方案效果、投资、降温系统运行稳定性、井筒输冷管路安装、矿井制冷水质、井下制冷排热等方面综合考虑,适合孔庄煤矿特点的集中降温途径只能是真空制冰降温方案,为矿井三期改扩建工程按期投产、验收创造了条件.同时,该降温工程的实施必将填补我国在矿井集中降温领域的一项技术空白,并在制冰技术、输冰管道、输冰工艺、压风冷却、井下融冰工艺、制冰节能技术上取得突破,进而推动我国煤矿降温制冷工艺的创新和发展.
Institute of Scientific and Technical Information of China (English)
田玉凯
2011-01-01
萨中油田中区西部产能建设位于大庆油田萨中开发区中部,该区域为已开发区块,区域内有已建各种站共30座,并有备勇村、登峰村、铁人二村、井下做业公司、大庆市百货公司、体育馆、儿童公园、友谊装饰材料市场、联谊商场、六中等居住区和商业区,地面建(构)筑物、生产设施等约占开发区域的68%,地面建设困难,通过采取地上地下一体化优化、布局优化、工艺简化、参数优化等优化简化措施,使该区块得到了经济有效开发.%Sa oil field of eapacity building is located in West Mesa in the Daqing oil field in central zone, the region, as a development block, has built a total of 30 various stations and Fenyong village, Dengfeng village, the Iron man of the village, industry companies in the well, Daqing department stores, gym, children's park, friendship decoration materials market, recreational shopping malls, six residential and commercial middle-ground building (structure) , building materials, production facilities, development of the region account for about 68％ developed ground construction, for the difficulty on the ground, through taking below ground integrated optimization, layout optimization, process simplification, optimization and other optimization simplification, the block has been cost-effectively developed.
Rizzetti, Tiele M; Kemmerich, Magali; Martins, Manoel L; Prestes, Osmar D; Adaime, Martha B; Zanella, Renato
2016-04-01
In this study, different extraction procedures based on the QuEChERS method were compared for the multiresidue determination of pesticides in orange juice by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). After choosing preliminary conditions, an experimental design was carried out with the variables C18, PSA, NaOH and CH3COONa to optimize the sample preparation step. The validation results of the validation were satisfactory, since the method presented recoveries between 70% and 118%, with RSD lower than 19% for spike levels between 10 and 100 μg L(-1). The method limit of detection (LOD) and limit of quantification (LOQ) ranged from 3.0 to 7.6 μg L(-1) and from 4.9 to 26 μg L(-1), respectively. The method developed was adequate for the determination of 74 pesticide residues in orange juice.
Energy Technology Data Exchange (ETDEWEB)
Grubelich, Mark C.; Su, Jiann-Cherng; Knudsen, Steven D.
2017-02-28
A centralizer assembly is disclosed that allows for the assembly to be deployed in-situ. The centralizer assembly includes flexible members that can be extended into the well bore in situ by the initiation of a gas generating device. The centralizer assembly can support a large load carrying capability compared to a traditional bow spring with little or no installation drag. Additionally, larger displacements can be produced to centralize an extremely deviated casing.
Institute of Scientific and Technical Information of China (English)
刘圣; 苏丹; 唐丽琴; 陈象青; 张善堂; 方卫
2011-01-01
目的:优化熊果苷乳膏配方,并建立制剂质量控制方法.方法:采用星点设计-效应面法,以乳膏伸展性为指标,优化十六醇、十二烷基硫酸钠-三乙醇胺(2:1)和二甲基硅油用量;考察配方优化后制剂的外观性状、粒度、pH、伸展性、稳定性和熊果苷含量.结果:优化的配方是十六醇用量为60g,十二烷基硫酸钠-三乙醇胺(2:1)用量为10g,二甲基硅油用量为25g;乳膏伸展性较好,延展直径约58.7mm,符合半流体乳膏特性;pH为6.2;稳定性较好;熊果苷含量为标示量的94.5%.结论:星点设计-效应面法优化的熊果苷乳膏配方稳定、可行.%OBJECTIVE: To optimize the formula of Arbutin cream, and to establish its quality control method.METHODS:Using central composite design-respoase surface methodology, the formula of Arbutin cream was optimized using the spreadability of cream as index and with the amounts of cetyl alcohol, sodium lauryl sulfate-triethanolamine(2: 1)and dimethicone as independent variables.The appearance characteristic, article size, pH value, spreadability, stability of preparation and the content of arbutin were studied.RESULTS: The optimal conditions were cetyl alcohol 60 g,sodium lauryl sulfate-triethanolamine(2: 1) 10 g, and dimethicone 25 g.According to the optimal conditions,the diameter of spreadability of prepared cream was about 58.7 mm,and cream suited with the property of semi-fluid cream.The pH value of cream ranged was 6.2.The content of arbutin was 94.5％ of labeling amount.CONCLUSION:Central composite design-response surface methodology is stable and feasible.
Energy Technology Data Exchange (ETDEWEB)
Paz, C. de la
2013-02-01
The main objective of this research is the development of a location methodology for sitting optimization of small hydro power (SHP) centrals. In order of achieve this goal, a Multi-Criteria Evaluation (MCE) methodology implemented through the use of tools in a GIS environment: Spatial Analysis, Geostatistic Analysis, and Hydrology have been developed. This methodology includes two different models based on the same MCE process. The substantial difference of both models is in the input data and the tools applied to estimate the energy resource and the principal factor of the methodology (caudal or accumulated flow). The first model is generated from caudal data obtained in the study area (El Bierzo), and the second one from pluviometric data and Digital Terrain Model (DTM). Both models include viability maps with greater ability areas to locate SHP facilities. As an additional objective, the study allows contrasting the results of the two developed models to evaluate their similarity. (Author)
Static and dynamic stability of the guidance force in a side-suspended HTS maglev system
Zhou, Dajin; Cui, Chenyu; Zhao, Lifeng; Zhang, Yong; Wang, Xiqing; Zhao, Yong
2017-02-01
The static and dynamic stability of the guidance force in a side-suspended HTS-PMG (permanent magnetic guideway) system were studied theoretically and experimentally. It is found that there are two types of guidance force that exist in the HTS-PMG system, which are sensitive to the levitation gap and the arrangement of YBCO bulks around the central axis of the PMG. An optimized YBCO array was used to stabilize the system, which enabled a side-suspended HTS-PMG maglev vehicle to run stably at 102 km h-1 on a circular test track with 6.5 m in diameter.
Energy Technology Data Exchange (ETDEWEB)
Morana, B. [Dpto. Tecnologia Electronica, E.T.S.I. de Telecomunicacion, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Sande, J.C.G. de [Dpto. Ingenieria de Circuitos y Sistemas, E.U.I.T. de Telecomunicacion, Universidad Politecnica de Madrid, 28031 Madrid (Spain); Rodriguez, A. [Dpto. Tecnologia Electronica, E.T.S.I. de Telecomunicacion, Universidad Politecnica de Madrid, 28040 Madrid (Spain)], E-mail: andres.rodriguez.dominguez@upm.es; Sangrador, J.; Rodriguez, T. [Dpto. Tecnologia Electronica, E.T.S.I. de Telecomunicacion, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Avella, M.; Jimenez, J. [Dpto. Fisica de la Materia Condensada, E.T.S.I. Industriales, Universidad de Valladolid, 47011 Valladolid (Spain)
2008-02-15
Si oxide films with a controlled excess of Si were deposited on Si wafers by LPCVD using Si{sub 2}H{sub 6} and O{sub 2}, thermally annealed to 1100 deg. C for 1 h to form Si nanocrystals embedded in SiO{sub 2} and subsequently annealed at 450 deg. C in forming gas. The samples were characterized by Fourier transform infrared spectroscopy, spectroscopic ellipsometry and cathodoluminescence spectroscopy. The excess of Si in the as-deposited samples, ranging from 0 to 70% in volume, was obtained from the ellipsometry data analysis. After annealing at 1100 deg. C, the samples show a luminescence band (peaking at 665 nm) at 80 K and at room temperature which is associated to the presence of Si nanocrystals. The growth rate, the excess of Si incorporated to the films and the intensity of the luminescence band were modelled using a Face-Centered Central Composite Design as a function of the main deposition variables (pressure, 185-300 mTorr; temperature, 250-400 deg. C; Si{sub 2}H{sub 6}/O{sub 2} flow ratio, 2-5) aiming to control the growth process and the incorporation of Si in excess as well as to determine the experimental conditions that yield the samples with the maximum intensity of the luminescence emission.
Subha, B; Muthukumar, M
2012-01-01
Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (R(2)) of VSS and COD reduction were 0.9689 and 0.8838, respectively. VSS reduction (81%) was achieved at acidic pH 6.9, 12 minutes ozonation, and retention time of 10 days. COD reduction (87%) was achieved at acidic pH 6.7, 8 minutes of ozonation time, and retention time of 6 days. Low ozonation time and high retention time influence maximum sludge reduction, whereas low ozonation time with low retention time was effective for COD reduction.
Institute of Scientific and Technical Information of China (English)
文佑英; 赵文英; 岳莉; 张丹丹; 胡相靖
2011-01-01
The pomegranate seed oil is micro-encapsulated with HI-CAP100, a kind of modified starch, and the main factors affecting the encapsulation efficiency of microcapsules are optimized by central composite design and response surface method. Under the premise of the oil content 40 ％,the optimizing parameters were obtianed as follows: the solid mass content 23.5％, the inlet air temperature in spray-drying process 195 ℃, the atomization pressure 0.20 MPa, and the input speed 24 mL·min-1 , thus the encapsulation efficiency of micro-capsules was 85. 6 ％. On this condition, the practical encapsulation efficiency agreed with the value predicted by central composite design and response surface method(86.2％), and the optimum condition was reasonable and practicable.%以辛烯基琥珀酸酯化淀粉(HI-CAP100)为囊材用喷雾干燥法制备石榴籽油微囊,并用星点设计-效应面优化法对影响微囊包封率的主要因素,包括固形物含量、进风温度、雾化压力、进液速度进行考察.在微囊含油量40%前提下,得出最佳工艺条件:固形物含量23.5%(质量分数)、进风温度195℃、雾化压力0.20 MPa、进液速度24 mL·min-1,在此条件下所得石榴籽油微胶囊平均包封率达85.6%,与预测值(86.2%)基本吻合,优化得到的工艺条件合理、稳定可行.
Without the strong force, there could be no life. The carbon in living matter is synthesised in stars via the strong force. Lighter atomic nuclei become bound together in a process called nuclear fusion. A minor change in this interaction would make life impossible. As its name suggests, the strong force is the most powerful of the 4 forces, yet its sphere of influence is limited to within the atomic nucleus. Indeed it is the strong force that holds together the quarks inside the positively charged protons. Without this glue, the quarks would fly apart repulsed by electromagnetism. In fact, it is impossible to separate 2 quarks : so much energy is needed, that a second pair of quarks is produced. Text for the interactive: Can you pull apart the quarks inside a proton?
Ziadi, Manel; Ben Hassen-Trabelsi, Aida; Mekni, Sabrine; Aïssi, Balkiss; Alaya, Marwen; Bergaoui, Latifa; Hamdi, Moktar
2017-01-01
This paper opens up a new issue dealing with Luffa cylindrica (LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, α-cellulose (45.80% ± 1.3), hemicelluloses (20.76% ± 0.3), and lignins (13.15% ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with Saccharomyces cerevisiae. LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%. PMID:28243606
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Kaouther Zaafouri
2017-01-01
Full Text Available This paper opens up a new issue dealing with Luffa cylindrica (LC lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, α-cellulose (45.80% ± 1.3, hemicelluloses (20.76% ± 0.3, and lignins (13.15% ± 0.6. The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with Saccharomyces cerevisiae. LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.
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Moumita Karmakar
2011-01-01
Full Text Available The production cost of β-glucosidase and endoglucanase could be reduced by using water hyacinth, an aquatic weed, as the sole carbon source and using cost-efficient fermentation strategies like solid-state fermentation (SSF. In the present study, the effect of different production conditions on the yield of β-glucosidase and endoglucanase by Rhizopus oryzae MTCC 9642 from water hyacinth was investigated systematically using response surface methodology. A Central composite experimental design was applied to optimize the impact of three variables, namely, substrate concentration, pH, and temperature, on enzyme production. The optimal level of each parameter for maximum enzyme production by the fungus was determined. Highest activity of endoglucanase of 495 U/mL was achieved at a substrate concentration of 1.23%, pH 7.29, and temperature 29.93°C whereas maximum β-glucosidase activity of 137.32 U/ml was achieved at a substrate concentration of 1.25%, pH 6.66, and temperature 32.09°C. There was a direct correlation between the levels of enzymatic activities and the substrate concentration of water hyacinth as carbon source.
Mohammadi, Abdorreza; Tavakoli, Rouya; Kamankesh, Marzieh; Rashedi, Hamid; Attaran, Abdolmohammad; Delavar, Mostafa
2013-12-01
A simple and highly sensitive analytical methodology for isolation and determination of patulin in apple-juice samples, based on enzyme-assisted extraction (EAE) and ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) was developed and optimized. Enzymes play essential roles in eliminating interference and increasing the extraction efficiency of patulin. Apple-juice samples were treated with pectinase and amylase. A mixture of 80 μL ionic liquid and 600 μL methanol (disperser solvent) was used for the IL-DLLME process. The sedimented phase was analyzed by high-performance liquid chromatography (HPLC). Experimental parameters controlling the performance of DLLME, were optimized using response surface methodology (RSM) based on central composite design (CCD). Under optimum conditions, the calibration curves showed high levels of linearity (R(2)>0.99) for patulin in the range of 1-200 ng g(-1). The relative standard deviation (RSD) for the seven analyses was 7.5%. The limits of detection (LOD) and limits of quantification (LOQ) were 0.15 ng g(-1) and 0.5 ng g(-1), respectively. The merit figures, compared with other methods, showed that new proposed method is an accurate, precise and reliable sample-pretreatment method that substantially reduces sample matrix interference and gives very good enrichment factors and detection limits for investigation trace amount of patulin in apple-juice samples.
Without the weak force, the sun wouldn't shine. The weak force causes beta decay, a form of radioactivity that triggers nuclear fusion in the heart of the sun. The weak force is unlike other forces: it is characterised by disintegration. In beta decay, a down quark transforms into an up quark and an electron is emitted. Some materials are more radioactive than others because the delicate balance between the strong force and the weak force varies depending on the number of particles in the atomic nucleus. We live in the midst of a natural radioactive background that varies from region to region. For example, in Cornwall where there is a lot of granite, levels of background radiation are much higher than in the Geneva region. Text for the interactive: Move the Geiger counter to find out which samples are radioactive - you may be surprised. It is the weak force that is responsible for the Beta radioactivity here. The electrons emitted do not cross the plastic cover. Why do you think there is some detected radioa...
Institute of Scientific and Technical Information of China (English)
周文杰; 傅亚; 王云红; 张小梅; 柯秀梅; 刘楠; 杨荣平
2013-01-01
Objective: To optimize processing technology conditions of Scrophularia ningpoensis. Method; Central composite design and response surface method was used with soaking time, steaming time, drying temperature as factors, OD of change ratio of harpagide, cinnamic acid and harpagoside as index, mathematical model of index and factors were established by multi-linear regression and binomial fitting, and to predict optimum processing technology of S. ningpoensis. Result: Optimal conditions were as followings; soaking time 19 min, steaming time 1. 2 h, drying temperature 49 ℃. Deviation of predicted and measured value was less than 2. 65%. Conclusion: Optimized processing technology was stable, reliable and feasible, it could provide experimental evidence for quality standards research of S. ningpoensis.%目的:优选玄参的炮制工艺条件.方法:采用中心复合设计-效应面法,以浸泡时间、蒸制时间、干燥温度为考察因素,哈帕苷、哈帕俄苷、肉桂酸变化率的总评归一值(OD)为指标,进行中心复合设计试验,并用多元线性回归及二项式拟合建立指标与因素间的数学模型,预测玄参的最佳炮制工艺.结果:最佳工艺为浸泡19 min,蒸制1.2h,干燥温度49℃.预测值与实测值偏差均＜2.65％.结论:采用中心复合设计-效应面法优化的玄参炮制工艺稳定可行,结果可靠,为玄参的质量标准研究提供实验依据.
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JOSÉ RUTLLANT
2002-03-01
Full Text Available The physical forcing of the upwelling along the subtropical west coasts of the continents encompasses a broad range of time scales which shape both phytoplankton biomass (Chl-a and primary productivity (carbon fixation changes over any given time interval. The narrow continental shelf and the steep alongshore orography off north-central Chile provide for a unique combination of year-round, upwelling-favorable winds with quasi-weekly upwelling pulses associated with atmospheric coastal-trapped disturbances (coastal lows. This variability is modulated by intraseasonal oscillations in the depth of the thermo/nutricline, produced by coastal-trapped waves in the ocean, upon which annual (seasons and interannual (ENSO cycles are superimposed. During coastal field experiments off Cruz Grande bay (29º S, carried on in November 1987 and 1988 (opposite extremes of the ENSO cycle, mean changes of the phytoplankton-integrated Chl-a (B and carbon fixation rate (PP from the active to the relaxed phases of the local upwelling forcing cycle (phyto-pattern were characterized. Those data were contrasted against similar ones reported off Punta Lengua de Vaca (Coquimbo, 30º S and off Mejillones peninsula (Antofagasta, 23º S, encompassing different seasons and phases of intraseasonal and interannual (ENSO cycles from 1992 to 1997. A "warm" phyto-pattern was schematically characterized by a significant increase in B and a quasi-steady evolution of PP from the active to the relaxed phases of one complete upwelling event. Conversely, relative small changes in B and a significant increase in PP characterized a "cold" phyto-pattern. It is proposed here that the ENSO "cold/warm" signal may be offset by more than one opposite "thermal" condition (seasonal and/or intraseasonal in defining a "warm" or "cold" phyto-pattern associated with a particular cycle of the local upwelling forcingEl forzamiento físico de la surgencia a lo largo de las costas occidentales de los
Contingency contractor optimization.
Energy Technology Data Exchange (ETDEWEB)
Gearhart, Jared Lee; Adair, Kristin Lynn; Jones, Katherine A.; Bandlow, Alisa; Durfee, Justin David.; Jones, Dean A.; Martin, Nathaniel; Detry, Richard Joseph; Nanco, Alan Stewart; Nozick, Linda Karen
2013-10-01
The goal of Phase 3 the OSD ATL Contingency Contractor Optimization (CCO) project is to create an engineering prototype of a tool for the contingency contractor element of total force planning during the Support for Strategic Analysis (SSA). An optimization model was developed to determine the optimal mix of military, Department of Defense (DoD) civilians, and contractors that accomplishes a set of user defined mission requirements at the lowest possible cost while honoring resource limitations and manpower use rules. An additional feature allows the model to understand the variability of the Total Force Mix when there is uncertainty in mission requirements.
Contingency contractor optimization.
Energy Technology Data Exchange (ETDEWEB)
Gearhart, Jared Lee; Adair, Kristin Lynn; Jones, Katherine A.; Bandlow, Alisa; Detry, Richard Joseph; Durfee, Justin David.; Jones, Dean A.; Martin, Nathaniel; Nanco, Alan Stewart; Nozick, Linda Karen
2013-06-01
The goal of Phase 3 the OSD ATL Contingency Contractor Optimization (CCO) project is to create an engineering prototype of a tool for the contingency contractor element of total force planning during the Support for Strategic Analysis (SSA). An optimization model was developed to determine the optimal mix of military, Department of Defense (DoD) civilians, and contractors that accomplishes a set of user defined mission requirements at the lowest possible cost while honoring resource limitations and manpower use rules. An additional feature allows the model to understand the variability of the Total Force Mix when there is uncertainty in mission requirements.
基于平均压溃力的轿车前端结构优化方法%Optimizing Method of Car Front-end Structure Based on Average Collapse Force
Institute of Scientific and Technical Information of China (English)
刘维海; 程秀生; 朱学武; 马志良
2011-01-01
In the initial stage of passenger car design and development, an ideal front-end structure is obtained with consideration of three crash modes of the 16 km/h frontal 40% offset rigid barrier crash, 50 km/h frontal rigid barrier crash and 56 km/h frontal 40% offset deformable barrier crash to conduct structural optimization analysis with the aim of average collapse force sustained by the front-end structure in frontal crash. Then the optimized structure was validated in vehicle crash simulation. Results show that the structure has good crashworthiness in vehicle crash analysis.%在某轿车设计开发初期阶段,以其前端结构在正面碰撞过程中所受到的平均压溃力为优化目标,综合考虑16 km/h正面40％偏置刚性壁碰撞、50 km/h正面刚性墙碰撞和56 km/h正面40％可变形壁偏置碰撞等3种碰撞模式进行结构优化分析,得到较好的车辆前端结构.在具备整车碰撞分析条件下,将优化结构进行整车碰撞仿真验证.仿真结果表明,优化后的前端结构在整车碰撞分析中表现理想.
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Amneet Pal Singh Bhalla
Full Text Available A fundamental issue in locomotion is to understand how muscle forcing produces apparently complex deformation kinematics leading to movement of animals like undulatory swimmers. The question of whether complicated muscle forcing is required to create the observed deformation kinematics is central to the understanding of how animals control movement. In this work, a forced damped oscillation framework is applied to a chain-link model for undulatory swimming to understand how forcing leads to deformation and movement. A unified understanding of swimming, caused by muscle contractions ("active" swimming or by forces imparted by the surrounding fluid ("passive" swimming, is obtained. We show that the forcing triggers the first few deformation modes of the body, which in turn cause the translational motion. We show that relatively simple forcing patterns can trigger seemingly complex deformation kinematics that lead to movement. For given muscle activation, the forcing frequency relative to the natural frequency of the damped oscillator is important for the emergent deformation characteristics of the body. The proposed approach also leads to a qualitative understanding of optimal deformation kinematics for fast swimming. These results, based on a chain-link model of swimming, are confirmed by fully resolved computational fluid dynamics (CFD simulations. Prior results from the literature on the optimal value of stiffness for maximum speed are explained.
Ponedel, Benjamin; Knobloch, Edgar
2016-11-01
We study spatial localization in the real subcritical Ginzburg-Landau equation ut =m0 u +m1 cos2/π l x u +uxx +d | u | 2 u -| u | 4 u with spatially periodic forcing. When d > 0 and m1 = 0 this equation exhibits bistability between the trivial state u = 0 and a homogeneous nontrivial state u =u0 with stationary localized structures which accumulate at the Maxwell point m0 = - 3d2 / 16 . When spatial forcing is included its wavelength is imprinted on u0 creating conditions favorable to front pinning and hence spatial localization. We use numerical continuation to show that under appropriate conditions such forcing generates a sequence of localized states organized within a snakes-and-ladders structure centered on the Maxwell point, and refer to this phenomenon as forced snaking. We determine the stability properties of these states and show that longer lengthscale forcing leads to stationary trains consisting of a finite number of strongly localized, weakly interacting pulses exhibiting foliated snaking.
Institute of Scientific and Technical Information of China (English)
欧江波
2012-01-01
广州市作为华南地区的中心城市和特大型城市,产业结构正于转型升级的关键时期。通过对当前广州市产业空间结构的特征及存在问题分析研究,在工业化和城市化进程加速推进的背景下,提出了产业空间结构调整与优化的基本思路,以保证广州可持续发展。%As a large central city of South-China,Guangzhou is in the key period of industrial transformation.Firstly,this paper deals with the spatial structure of Guangzhou' industries,and puts forward that the spatial structure has gone through four stages in different historical periods;Secondly,it analyzes the spatial structure characteristics of Guangzhou' industries,and points out that the industries are in circle structures of distribution as a whole,through spatial expansion;Finally,it gives out the basic strategies of regulating and optimizing spatial structure under the background of accelerating industrialization and urbanization,.i e.in accordance with demanding as a modern international large city,Changchun should break through the existing mode of industrial spaces,adopt the pattern of park agglomeration according to organic dispersing principle,form a new industrial spatial allocation in which the main city,sub-city,groups,and key central towns are relatively independent orderly ranked,stressing on main points,in order to assure Guangzhou' sustainable development.
Buckingham, A D
1975-11-06
The nature of molecular interactions is examined. Intermolecular forces are divided into long-range and short-range components; the former operate at distances where the effects of electron exchange are negligible and decrease as an inverse power of the separation. The long-range interactions may be subdividied into electrostatic, induction and dispersion contributions, where the electrostatic component is the interaction of the permanent charge distributions and the others originate in the fluctuations in the distributions. Typical magnitudes of the various contributions are given. The forces between macroscopic bodies are briefly considered, as are the effects of a medium. Some of the manifestations of molecular interactions are discussed.
Asadollahzadeh, Mehdi; Tavakoli, Hamed; Torab-Mostaedi, Meisam; Hosseini, Ghaffar; Hemmati, Alireza
2014-06-01
Dispersive-solidification liquid-liquid microextraction (DSLLME) coupled with electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of inorganic arsenic (III, V) in water samples. At pH=1, As(III) formed complex with ammonium pyrrolidine dithiocarbamate (APDC) and extracted into the fine droplets of 1-dodecanol (extraction solvent) which were dispersed with ethanol (disperser solvent) into the water sample solution. After extraction, the organic phase was separated by centrifugation, and was solidified by transferring into an ice bath. The solidified solvent was transferred to a conical vial and melted quickly at room temperature. As(III) was determined in the melted organic phase while As(V) remained in the aqueous layer. Total inorganic As was determined after the reduction of the pentavalent forms of arsenic with sodium thiosulphate and potassium iodide. As(V) was calculated by difference between the concentration of total inorganic As and As(III). The variable of interest in the DSLLME method, such as the volume of extraction solvent and disperser solvent, pH, concentration of APDC (chelating agent), extraction time and salt effect, was optimized with the aid of chemometric approaches. First, in screening experiments, fractional factorial design (FFD) was used for selecting the variables which significantly affected the extraction procedure. Afterwards, the significant variables were optimized using response surface methodology (RSM) based on central composite design (CCD). In the optimum conditions, the proposed method has been successfully applied to the determination of inorganic arsenic in different environmental water samples and certified reference material (NIST RSM 1643e).
Satellite Constellation Optimization for Turkish Armed Forces
2013-03-01
investigate and demonstrate the feasibility of the design, 9 Jeff Foust , “Emerging Opportunities for Low-Cost...Jeff Foust , “Smallsats on the Rise,” Space Quarterly Magazine, December 17, 2012, URL: http://spaceref.biz/2012/12/smallsats-on-the-rise.html. 13 Ibid...October 06, 2011, http://www.sstl.co.uk/News---Events/2011- News-Archive?story=1899 under “News&Events.” 18 Foust , “Smallsats on the Rise.” 19
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Marcelo de Carvalho Griebeler
2015-09-01
Full Text Available There has been in some countries a trend of assigning other functions to central banks besides price stability. The most suggested function to be added to monetary authority’s obligations is to pursue economic growth or full employment. In this paper we characterize the behavior and analyse the optimal monetary policy of, what we call, a naive central banker. We describe the naive behavior as one that does face the inflation-unemployment trade-off, but it tries to minimize both variables simultaneously. Our findings, both under discretion and commitment, indicate that the naive central banker delivers lower expected inflation and inflation variance than the benchmark behavior whenever the economy is rigid enough. However, the degree of conservativeness also affects this result, such that the less conservative the naive policymaker, the more rigidity is necessary.
Institute of Scientific and Technical Information of China (English)
马丽娜; 白曼; 王景媛; 史亚军; 王昌利
2013-01-01
目的 优选川芎总生物碱的提取工艺.方法 对川芎采用乙醇回流提取的方法,进行星点设计,以乙醇浓度、醇倍数、提取时间为自变量,以川芎中总生物碱含量为因变量,通过对自变量各水平的多元线性回归及二项式拟合,用响应面法优选出最佳提取工艺,同时进行预测分析.结果 确定了最佳提取工艺为用8倍90％的乙醇提取2次,每次2h,提取的川芎总生物碱含量为0.693 mg·g-1,二项式拟合复相关系数R2=0.957 3.结论 星点设计-响应面法优选川芎中总生物碱的提取工艺,方法简单,精密度高,可预测性好.%Objective To optimize the extraction process of total alkaloids from Ligusticum chuanxiong. Methods Independent variables were ethanol concentration, reflux time and solvent fold, and dependent variable was extraction rate of total alkaloids from Ligusticum chuanxiong. Levels of independent variables were regressed by multiple linearity and fitted by binomial. Response surface methodology was used to optimize the extraction process. We compared both observed and predicted values. Results Optimal extraction technology was: extracting twice by 8 times of 90% ethanol for 2 h each time. The optimum extraction process of total alkaloid content in Ligusticum chuanxiong was under 0.693 mg · g-1. Regression coefficients of binomial fitting complex model was as high as 0.957 3. Conclusion This extraction process of total alkaloids from Ligusticum chuanxiong by central composite design/response surface methodology is simple with high precision and good predictability.
Design of force-cooled conductors for large fusion magnets
Energy Technology Data Exchange (ETDEWEB)
Dresner, L.; Lue, J.W.
1977-01-01
Conductors cooled by supercritical helium in forced convection are under active consideration for large toroidal fusion magnets. One of the central problems in designing such force cooled conductors is to maintain an adequate stability margin while keeping the pumping power tolerably low. A method has been developed for minimizing the pumping power for fixed stability by optimally choosing the matrix-to-superconductor and the metal-to-helium ratios. Such optimized conductors reduce pumping power requirements for fusion size magnets to acceptable limits. Furthermore, the mass flow and hence pumping losses can be varied through a magnet according to the local magnetic field and magnitude of desired stability margin. Force cooled conductors give flexibility in operation, permitting, for example, higher fields to be obtained than originally intended by lowering the bath temperature or increasing the pumping power or both. This flexibility is only available if the pumping power is low to begin with. Scaling laws for the pumping requirement and stability margin as functions of operating current density, number of strands and such physical parameters as stabilizer resistivity and critical current density, have been proved. Numerical examples will be given for design of conductors intended for use in large toroidal fusion magnet systems.
Institute of Scientific and Technical Information of China (English)
谢卫民
2016-01-01
Based on Shanxi central southern railway corridor, a vehicle/track dynamics model is established to conduct a comprehensive assessment of typical line sections. Taking the flat profile parameters of the original design and the optimized design as boundary condition, the dynamics performances of vehicles of 30 t wagon and passenger car passing through these railway locations are compared and applicable circular curve radius for 30 t axle load heavy haul railway is recommended, which may be used as reference for future heavy haul railway design.%依托山西中南部铁路通道工程，建立车线系统动力学模型，选取典型区段线路设计方案进行全面的动力学评估。以发鸠山隧道改线方案原设计和优化后设计的线路平纵断面参数作为线路条件，对比30 t货车和客车通过时的动力学性能指标，给出适用于30 t大轴重的重载铁路圆曲线半径建议值，可供未来重载铁路线路设计参考。
Mosleh, S; Rahimi, M R; Ghaedi, M; Dashtian, K
2016-09-01
An efficient simultaneous sonophotocatalytic degradation of trypan blue (TB) and vesuvine (VS) using Ag3PO4/Bi2S3-HKUST-1-MOF as a novel visible light active photocatalyst was carried out successfully in a continuous flow-loop reactor equipped to blue LED light. Ag3PO4/Bi2S3-HKUST-1-MOF with activation ability under blue light illumination was synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), photoluminescence (PL) and diffuse reflectance spectra (DRS). The effect of operational parameters such as the initial TB and VS concentration (5-45mg/L), flow rate (30-110mL/min), irradiation and sonication time (10-30min), pH (3-11) and photocatalyst dosage (0.15-0.35g/L) has been investigated and optimized using central composite design (CCD) combined with desirability function (DF). Maximum sonophotodegradation percentage (98.44% and 99.36% for TB and VS, respectively) was found at optimum condition set as: 25mg/L of each dye, 70mL/min of solution flow rate, 25min of irradiation and sonication time, pH 6 and 0.25g/L of photocatalyst dosage. At optimum conditions, synergistic index value was obtained 2.53 that indicated the hybrid systems including ultrasound irradiation and photocatalysis have higher efficiency compared with sum of the individual processes.
Institute of Scientific and Technical Information of China (English)
林卫瑞; 王洪光; 杜昌余
2013-01-01
Objective To optimize the preparation technology of florfenicol sustained release microspheres by complex coacervation method.Method Microspheres were prepared by complex coacervation method.The effects of influence factors such as concentration of material (gelatin,gum arabic),encysted pH and stirring speed,on overall desirability (OD) of diameter and entrapment efficiency were investigated by using central composite design and response surface method.The data were imitated using second-order polynomial.Microspheres prepared by optimal condition were releasing in vitro in artificial body fluid.Results The optimal conditions are as follow:concentration of material as 2.2％,encysted pH as 3.9,and stirring speed as 450r/min.The microspheres prepared by optimal condition were round and uniform with particle size of 50tm.The entrapment efficiency was 51.80％,drug loading could reach 14.29％.By which,the microspheres had good slow-release characteristics in Hank's artificial body fluid.Conclusion Microspheres prepared by optimal method had better drug loading with good shape.The slow-release characteristics were good.%目的 优化复凝聚法制备氟苯尼考缓释微球工艺.方法 以复凝聚法制备微球,以粒径、包封率的总评“归一值”为评价指标,采用星点设计,考察囊材(明胶、阿拉伯胶)浓度、成囊pH、搅拌速度撒三因素对制备微球的影响,对结果进行二项式拟合,效应面法选取最佳工艺条件,优化工艺后制得的微球在人工体液中进行体外释放.结果 最佳工艺条件为囊材浓度2.2％、成囊pH3.9、搅拌速度450r/min;制得的微球圆整均一,粒径50μm左右,包封率51.80％,载药量可达14.29％;制得的微球在Hank′s人工模拟体液中有良好的缓释特征.结论 优化制备工艺条件下制得的微球外形良好载药量较大,缓释效果好.
Optimal model of loan portfolio based on the higher central-moment constraints%基于高阶矩风险控制的贷款组合优化模型
Institute of Scientific and Technical Information of China (English)
迟国泰; 吴灏文; 闫达文
2012-01-01
By using VaR as risk control of the loans portfolio, using skewness constrain to avoid the distribution of loan portfolio yield toward left of mean to reduce left side risk of general risk, using kurtosis constrain as the control of the distribution's fat tail on both sides to reduce the extreme loss, the optimal model of loan portfolio which targets the maximum rate of return on bank loans portfolio based on the higher central-moment constraints is set up. The contribution of this article is we identified the importance of using higher central-moments, especially the kurtosis in bank loans portfolio optimization. Addition to the classic Markowitz model, we build a mean-variance-skewness-kurtosis model which introduced kurtosis constrain to reduce the extreme loss, skewness constrain to avoid general risk and VaR as risk control of the loans portfolio. The model we built controls the portfolio's risk from multi-angle and extends the classic mean-variance optimal theory.%以银行各项资产组合收益率最大化为目标函数,以VaR来控制贷款组合的风险价值,以偏度约束来控制贷款组合收益率的整体分布向大于均值的方向倾斜、以减少发生总体损失的单侧风险,以峰度来控制贷款组合收益率分布出现极端情况的双侧风险,建立了资产分配的收益率均值-方差-偏度-峰度模型.本模型的创新与特色是通过峰度约束控制了贷款组合收益率向极端损失偏离的程度.在马可维茨均值-方差模型的基础上,增加了偏度和峰度参数,建立了收益率均值-方差-偏度-峰度模型.模型通过方差约束,控制了组合收益率偏离均值的离散程度:通过偏度约束,控制了组合收益率总体分布向损失一侧偏离的程度:通过峰度约束,控制了组合收益率出现极端损失或收益的可能性.模型从多个角度控制了贷款组合的风险,拓展了经典的均值-方差优化组合思路.
Institute of Scientific and Technical Information of China (English)
张家敏; 许德章
2016-01-01
Traditional BP neural network took advantages of approximating nonlinear systems with arbitrary precision to de-couple.But in the training process,there were some problems such as concussion,slow convergence speed and local extreme.The application was not ideal.This paper proposed an algorithm based on modified particle swarm BP neural network algorithm and it was applied to study six-axis force sensor decoupling.The algorithm avoided the lower accuracy of traditional linear decoupling al-gorithm,used PSO to optimize BP neural network,evaluated the solution resulted by training through fitness function,and followed the current optimal solution to search global optimum.Simulation results show that the algorithm is easy to be implemented as well as fast convergence and high decoupling precision which achieves the desired application effect.%传统BP神经网络解耦算法可实现六维力传感器解耦,但在训练过程中容易出现振荡,收敛速度慢,陷入局部极值等问题,应用效果不理想.文中提出一种基于改进粒子群BP神经网络算法,应用到六维力传感器解耦,提高了线性解耦算法精度,同时利用粒子群算法(PSO)对BP神经网络进行优化,利用适应度函数对训练过程中得到的解进行评价,追随当前最优解搜寻全局最优.实验仿真结果表明:在六维力传感器解耦应用中,该算法实现容易,收敛速度快,解耦精度高,达到了预期的应用效果.
Force decomposition in robot force control
Murphy, Steve H.; Wen, John T.
1991-01-01
The unit inconsistency in force decomposition has motivated an investigation into the force control problem in multiple-arm manipulation. Based on physical considerations, it is argued that the force that should be controlled is the internal force at the specified frame in the payload. This force contains contributions due to both applied forces from the arms and the inertial force from the payload and the arms. A least-squares scheme free of unit inconsistency for finding this internal force is presented. The force control issue is analyzed, and an integral force feedback controller is proposed.
Kobelev, V
2016-01-01
Bitter coil is an electromagnet used for the generation of exceptionally strong magnetic fields. The upper bound of magnet flux density is restricted by several factors. One principal restriction is the high stresses due to Lorentz forces in the coil. The Lorentz forces generate the distributed body force, which acts as the pressure of magnetic field. The common radial thickness profile of the Bitter coil is constant. In this paper the possibility of optimization by means of non-constant radial thickness profile of the Bitter coil is studied. The close form expression for optimal thickness profile is obtained. Both designs are compared and the considerable improvement of magnetic flux density is demonstrated. Moreover, the optimal design improves the shape of cooling channels. Namely, the highest cross-section of cooling channel is at the most thermally loaded inner surface of the coil.
Optimization and Optimal Control
Chinchuluun, Altannar; Enkhbat, Rentsen; Tseveendorj, Ider
2010-01-01
During the last four decades there has been a remarkable development in optimization and optimal control. Due to its wide variety of applications, many scientists and researchers have paid attention to fields of optimization and optimal control. A huge number of new theoretical, algorithmic, and computational results have been observed in the last few years. This book gives the latest advances, and due to the rapid development of these fields, there are no other recent publications on the same topics. Key features: Provides a collection of selected contributions giving a state-of-the-art accou
Optimally Stopped Optimization
Vinci, Walter; Lidar, Daniel A.
2016-11-01
We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark simulated annealing on a class of maximum-2-satisfiability (MAX2SAT) problems. We also compare the performance of a D-Wave 2X quantum annealer to the Hamze-Freitas-Selby (HFS) solver, a specialized classical heuristic algorithm designed for low-tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N =1098 variables, the D-Wave device is 2 orders of magnitude faster than the HFS solver, and, modulo known caveats related to suboptimal annealing times, exhibits identical scaling with problem size.
Force criterion of different electrolytes in microchannel
Institute of Scientific and Technical Information of China (English)
Ren Yu-Kun; Yan Hui; Jiang Hong-Yuan; Gu Jian-Zhong; Antonio Ramos
2009-01-01
The control and handling of fluids is central to many applications of the lab-on-chip. This paper analyzes the basic theory of manipulating different electrolytes and finds the two-dimensional model. Coulomb force and dielectric force belonging to the body force of different electrolytes in the microchannel were analyzed. The force criterion at the interface was concluded, and testified by the specific example. Three basic equations were analyzed and applied to simulate the phenomenon. The force criterion was proved to be correct based on the simulation results.
Consistent force fields for saccharides
DEFF Research Database (Denmark)
Rasmussen, Kjeld
1999-01-01
Consistent force fields for carbohydrates were hitherto developed by extensive optimization ofpotential energy function parameters on experimental data and on ab initio results. A wide range of experimental data is used: internal structures obtained from gas phase electron diffraction and from x-...
Institute of Scientific and Technical Information of China (English)
梁喆; 张丽; 吕艳莉; 陈惠铮
2012-01-01
To optimize the extraction technology of oral liquid for pneumonia.Methods; The inde-pendent variables were alcohol sediment concentration, liquid - material ratio and extraction time. The dependent variable was extraction rate of total extract from oral liquid for pneumonia. Linear or nonlinear mathematic models were used to estimate the relationship between independent and dependent variables. Central composite design and response surface methodology were used to optimize the process of extraction. The prediction was carried out through comparing the observed and predicted values. Results; The optimum technological parameters were as follows; alcohol sediment concentration 75. 76% , liquid - material ratio of 1:9. 19 and extraction time 2. 08 hours. The highest extraction rate of essential oil was 10. 46mg/ml which was agreed with model predictions. Conclusion;The extraction technology is simple, reliable and highly predictive.%目的:采用星点设计-响应面法优化肺炎口服液的提取工艺.方法:以醇沉浓度,料液比,提取时间为自变量,提取物总含量为因变量,通过对自变量各水平的多元线性回归及二项式拟合,用星点设计-响应面法选取最佳工艺,并进行预测分析.结果:最佳工艺条件为醇沉浓度75.76％,料液比1:9.19,提取时间2.08h,在此最佳条件下,肺炎口服液中提取物总含量的最大估计值为10.46mg/ml.实验结果与模型预测值相符.结论:方法简便合理,稳定,可预测性较优.
Measurement of edgewise torque force in vitro.
Steyn, C L
1977-05-01
The construction of a model for the measurement of palatal root torque is described. It was demonstrated that: 1. Halfway between the apex of a tooth and the arch wire the force was double that which was delivered at the apex. 2. The lateral incisors were subjected to appreciably more force than the central incisors. 3. The smaller the number of teeth acted upon, the greater the force they received.
Central line infections - hospitals
... infection; Central venous catheter - infection; CVC - infection; Central venous device - infection; Infection control - central line infection; Nosocomial infection - central line infection; Hospital acquired ...
DEFF Research Database (Denmark)
Christiansen, Anne Mette
2013-01-01
companies have over the last 23 years embraced the concept of strategic CSR and are increasingly engaging in cross-sector partnerships as part of their CSR strategy. The partnerships take different forms both in regards to number of partners, focus areas and level of strategic engagement. In the article......, a number of different partnerships are explored along with the motivation for the different partners for engaging. Finally, the role of a central partnership broker is examined and the author suggests that this has been instrumental in ensuring the emergence of the relatively high number of partnerships...
Central presbycusis: an emerging view.
Gates, George A
2012-07-01
Age-related dysfunction of the central auditory system (central presbycusis) is common but rarely looked for by those who provide aural rehabilitation. Patients who complain of difficulty hearing in noise--the key symptom of central presbycusis--are generally disadvantaged with conventional rehabilitation. This symptom should be documented with commercially available speech-in-noise tests, which use materials that are uncomplicated to administer. Those patients who perform poorly on such tests should have a customized rehabilitation program aimed at optimizing their remaining communication abilities. Otolaryngologists who provide auditory rehabilitation may wish to consider expanding their practices to meet the communication needs of older patients with central presbycusis. Central presbycusis is an emerging area for basic and clinical research in auditory neurotology, particularly in the relation of cognitive dysfunction to impaired auditory processing.
A SCALED CENTRAL PATH FOR LINEAR PROGRAMMING
Institute of Scientific and Technical Information of China (English)
Ya-xiang Yuan
2001-01-01
Interior point methods are very efficient methods for solving large scale linear programming problems. The central path plays a very important role in interior point methods. In this paper we propose a new central path, which scales the variables. Thus it has the advantage of forcing the path to have roughly the same distance from each active constraint boundary near the solution.
Institute of Scientific and Technical Information of China (English)
王光庆; 金文平; 展永政; 陆跃明
2013-01-01
为提高传统压电振动能量采集器集总参数模型的性能预测精度，考虑悬臂梁的振型信息与轴向应变分布情况，提出了一种改进的力电耦合模型，该模型引入无因次幅值修正因子，通过曲线拟合方法确定了修正因子与振型函数和振动幅值之间的关系表达式；利用Rayleigh-Ritz模态分析法确定了力电耦合模型中的集总等效参数(如质量、刚度等)，并根据弹性动力学原理建立了能量采集器的运动控制方程，得到了稳态时能量采集器的力、电输出响应表达式；最后，利用改进的模型对能量采集器的负载电阻和输出功率进行了优化，得到了负载短路和负载开路时能量采集器的最优输出特性。仿真结果与实例对比验证了提出模型的正确性，表明改进的力电耦合模型具有较高的预测精度。%In order to overcome the disadvantages of the traditional lumped parameter model of piezoelectric vibration energy harvester ( PVEH ) , this article presents an improved force-electric coupling model ( FECM ) to predict the output performances of the PVEH by considering the dynamic mode shape and the strain distribution of the bender. A dimensionless correction factor is adopted in the FECM to formulate the relationship expression between the mode shape and the vibration amplitude of the PVEH with curve fitting method. The equivalent parameters(such as mass,stiffness) of FECM are obtained by using the Rayleigh-Ritz modal analysis method,the governing motion equations and the exact analytical solution of cantilevered piezoelectric vibration energy harvester excited by persistent base motions are developed according to the elastic dynamics principle. The steady state electrical and mechanical output response expressions are derived for arbitrary frequency excitations. Finally,the op-timizations of the load resistance and the output power of the PVEH are carried out and the optimized output
2002-01-01
The Central Solenoid (CS) is a single layer coil wound internally in a supporting cylinder housed in the cryostat of the Liquid Argon Calorimeter. It was successfully tested at Toshiba in December 2000 and was delivered to CERN in September 2001 ready for integration in the LAr Calorimeter in 2003. An intermediate test of the chimney and proximity cryogenics was successfully performed in June 2002.
Directory of Open Access Journals (Sweden)
Karel BARTOSEK
2010-02-01
Full Text Available La investigación francesa continúa interesándose por Europa Central. Desde luego, hay límites a este interés en el ambiente general de mi nueva patria: en la ignorancia, producto del largo desinterés de Francia por este espacio después de la Segunda Guerra Mundial, y en el comportamiento y la reflexión de la clase política y de los medios de comunicación (una anécdota para ilustrar este ambiente: durante la preparación de nuestro coloquio «Refugiados e inmigrantes de Europa Central en el movimiento antifascista y la Resistencia en Francia, 1933-1945», celebrado en París en octubre de 1986, el problema de la definición fue planteado concreta y «prácticamente». ¡Y hubo entonces un historiador eminente, para quién Alemania no formaría parte de Europa Central!.
Directory of Open Access Journals (Sweden)
Branko Lobnikar
2006-11-01
Full Text Available The book is divided in two parts: the introduction and conclusion (by Marina Caparini and Otwin Marenin and several case studies of individual police organizations in Central and Eastern Europe. In the introduction, Caparini and Marenin emphasise the importance of the police in a democratic society. The main function of the police – the provision of security – is one of the basic demands laid against the state by its society. Democratic policing is described in the first part of the introduc...
Wind turbine pitch optimization
DEFF Research Database (Denmark)
Biegel, Benjamin; Juelsgaard, Morten; Stoustrup, Jakob
2011-01-01
for maximizing power production while simultaneously minimizing fatigue loads. In this paper, we show how this problem can be approximately solved using convex optimization. When there is full knowledge of the wind field, numerical simulations show that force and torque RMS variation can be reduced by over 96...
Kolosov, Oleg; Briggs, Andrew
Ultrasonic Force Microscopy, or UFM, allows combination of two apparently mutually exclusive requirements for the nanomechanical probe—high stiffness for the efficient indentation and high mechanical compliance that brings force sensitivity. Somewhat inventively, UFM allows to combine these two virtues in the same cantilever by using indention of the sample at high frequency, when cantilever is very rigid, but detecting the result of this indention at much lower frequency. That is made possible due to the extreme nonlinearity of the nanoscale tip-surface junction force-distance dependence, that acts as "mechanical diode" detecting ultrasound in AFM. After introducing UFM principles, we discuss features of experimental UFM implementation, and the theory of contrast in this mode, progressing to quantitative measurements of contact stiffness. A variety of UFM applications ranging from semiconductor quantum nanostructures, graphene, very large scale integrated circuits, and reinforced ceramics to polymer composites and biological materials is presented via comprehensive imaging gallery accompanied by the guidance for the optimal UFM measurements of these materials. We also address effects of adhesion and topography on the elasticity imaging and the approaches for reducing artifacts connected with these effects. This is complemented by another extremely useful feature of UFM—ultrasound induced superlubricity that allows damage free imaging of materials ranging from stiff solid state devices and graphene to biological materials. Finally, we proceed to the exploration of time-resolved nanoscale phenomena using nonlinear mixing of multiple vibration frequencies in ultrasonic AFM—Heterodyne Force Microscopy, or HFM, that also include mixing of ultrasonic vibration with other periodic physical excitations, eg. electrical, photothermal, etc. Significant section of the chapter analyzes the ability of UFM and HFM to detect subsurface mechanical inhomogeneities, as well as
Institute of Scientific and Technical Information of China (English)
许国燕
2015-01-01
节点部署是无线传感器网络(Wireless Sensor Network,简称WSN)设计的一个重要方面,它将会影响网络的有效覆盖,连通性和能耗.粒子群算法(Particle Swarm Optimization,简称PSO)可以提高目标区域无线传感器网络的覆盖率.然而该算法在优化过程中易早熟收敛,影响覆盖的优化效果,并且算法复杂度较高.针对该问题文章在量子粒子群算法(Quantum Particle Swarm Optimization,简称QPSO)的基础上,结合拟物力导向的思想,提出了基于拟物力导向的量子粒子群优化算法.通过仿真实验得出,该算法加快了粒子的收敛速度,提高了WSN的覆盖率,同时算法的复杂度降低.%Node deployment is an important aspect of wireless sensor network design, It will influence the effective network coverage , connectivity and power consumption. Particle swarm algorithm can improve the target area of wireless sensor net-work coverage. However, the algorithm in the optimization process is easy to premature convergence,influence the optimization effect and algorithm complexity is higher. Aiming at this problem, based on the quantum particle swarm optimization algorithm, the paper proposes a virtual material force-directed quantum particle swarm optimization algorithm based on the quasi physical force. Through the simulation experiment, this algorithm can speed up the convergence speed of particles, increase the coverage of WSN, and reduce the complexity of the algorithm.
Singh, Supreet
2014-12-01
Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. The topic addressed in this issue is central pain, a neuropathic pain syndrome caused by a lesion in the brain or spinal cord that sensitizes one's perception of pain. It is a debilitating condition caused by various diseases such as multiple sclerosis, strokes, spinal cord injuries, or brain tumors. Varied symptoms and the use of pharmacological medicines and nonpharmacological therapies will be addressed.
Directory of Open Access Journals (Sweden)
Manuel R. Piña Monarrez
2007-01-01
Full Text Available Dado que la Regresión Ridge (RR, es una estimación sesgada que parte de la solución de la regresión de Mínimos Cuadrados (MC, es vital establecer las condiciones para las que la distribución central t de Student que se utiliza en la prueba de hipótesis en MC, sea también aplicable a la regresión RR. La prueba de este importante resultado se presenta en este artículo.
Optimizing product lines and assortments
Rooderkerk, R.P.
2007-01-01
How should manufacturers and retailers optimize the sets of products they offer? Increasing product proliferation forces firms to solve these complex optimization problems ever more frequently. While the existing literature has made some headway in solving these problems, the three essays in this di
Directory of Open Access Journals (Sweden)
Ricardo Vilela
2010-12-01
Full Text Available OBJETIVO: Avaliar o impacto de intervenções interdisciplinares nos indicadores de infecção de corrente sanguínea relacionada ao cateter venoso central e microrganismos isolados, em uma Unidade de Terapia Intensiva Pediátrica. MÉTODOS: Estudo de intervenção do tipo antes e depois. Foi criado um programa educativo e constituída uma equipe interdisciplinar de intervenção composta por médicos e enfermeiros da unidade e do Serviço de Controle de Infecção Hospitalar. As intervenções foram compostas por medidas diretas e indiretas educativas e processuais. O período pré-intervenção (Fase 1, de junho de 2003 a maio de 2004, foi comparado ao período pós-intervenção nas Fases 2 (junho de 2004 a maio de 2005 e 3 (junho de 2005 a maio de 2006. As taxas de infecção foram comparadas por ANOVA, sendo significante pOBJECTIVE: To determine the impact of interdisciplinary interventions on central venous catheter-related bloodstream infections rates in a Pediatric Intensive Care Unit (PICU and on the bloodstream infection organisms. METHODS: Interventional study type before-and-after. An educational program was performed and an interdisciplinary team of interventions was created. This team was formed by nurses and doctors of the PICU and of the Infection Control Committee. The interventions were composed by direct and indirect educational and procedural measures. Task-force interventions were developed from Jun/2003 to May/2004. This pre-intervention period (Phase 1 was compared with two post-intervention periods: Phases 2 (Jun/2004 to May/2005 and 3 (Jun/2005 to May/2006. Central venous catheter-related bloodstream infection rates during the three periods were compared by ANOVA, being significant p<0.05. RESULTS: 1,234 patients were studied from June 1st 2003 to May 31, 2006. The number of central venous catheter-related bloodstream infections was 22.72 per 1,000 catheter-days in Phase 1, and 6.81 and 5.87 in Phases 2 and 3
The Structural Optimization of Trees
Mattheck, C.; Bethge, K.
1998-01-01
Optimization methods are presented for engineering design based on the axiom of uniform stress. The principle of adaptive growth which biological structures use to minimize stress concentrations has been incorporated into a computer-aided optimization (CAO) procedure. Computer-aided optimization offers the advantage of three-dimensional optimization for the purpose of designing more fatigue-resistant components without mathematical sophistication. Another method, called computer-aided internal optimization (CAIO), optimizes the performance of fiber-composite materials by aligning the fiber distribution with the force flow, again mimicking the structure of trees. The lines of force flow, so-called principal stress trajectories, are not subject to shear stresses. Avoiding shear stresses in the technical components can lead to an increase in maximum load capacity. By the use of a new testing device strength distributions in trees can be determined and explained based on a new mechanical wood model.
Weigh in Motion Based on Parameters Optimization
Institute of Scientific and Technical Information of China (English)
ZHOU Zhi-feng; CAI Ping; CHEN Ri-xing
2009-01-01
Dynamic tire forces are the main factor affecting the measurement accuracy of the axle weight of moving vehicle. This paper presents a novel method to reduce the influence of the dynamic tire forces on the weighing accuracy. On the basis of analyzing the characteristic of the dynamic tire forces, the objective optimization equation is constructed. The optimization algorithm is presented to get the optimal estimations of the objective parameters. According to the estimations of the parameters, the dynamic tire forces are separated from the axle weigh signal. The results of simulation and field experiments prove the effectiveness of the proposed method.
Cooperative Cognitive Networks: Optimal, Distributed and Low-Complexity Algorithms
Zheng, Gan; Wong, Kai-Kit; Ottersten, Bjorn
2012-01-01
This paper considers the cooperation between a cognitive system and a primary system where multiple cognitive base stations (CBSs) relay the primary user's (PU) signals in exchange for more opportunity to transmit their own signals. The CBSs use amplify-and-forward (AF) relaying and coordinated beamforming to relay the primary signals and transmit their own signals. The objective is to minimize the overall transmit power of the CBSs given the rate requirements of the PU and the cognitive users (CUs). We show that the relaying matrices have unit rank and perform two functions: Matched filter receive beamforming and transmit beamforming. We then develop two efficient algorithms to find the optimal solution. The first one has linear convergence rate and is suitable for distributed implementation, while the second one enjoys superlinear convergence but requires centralized processing. Further, we derive the beamforming vectors for the linear conventional zero-forcing (CZF) and prior zero-forcing (PZF) schemes, wh...
Institute of Scientific and Technical Information of China (English)
郑娟; 龙述尧; 李光耀
2011-01-01
In this paper,the element-free Galerkin method (EFG) is applied to carry out the topology optimization of the continuum structures subjected to a forced vibration. Considering the relative density of nodes as design variables,the minimization of dynamic compliance as an objective function,the mathematical formulation of the topology optimization is developed using the SIMP (solid isotropic microstructures with penalization) interpolation scheme. Sensitivity of the objective function is derived based on the adjoint method. The optimization formulation is solved by the optimality criteria method. Numerical examples show that the proposed approach is feasible and efficient for the topology optimization of the continuum structures subjected to a forced vibration.%基于无单元Galerkin法(EFG)对受迫振动下的连续体结构进行拓扑优化设计.选取节点的相对密度作为设计变量,以动柔度最小化为目标函数,基于带惩罚的各向同性固体材料模型(SIMP)建立了受迫振动下的连续体结构拓扑优化模型,采用伴随法求解得到目标函数的敏度分析公式,利用优化准则法对优化模型进行求解.通过经典的二维连续体结构拓扑优化算例证明了该方法的可行性和有效性.
Minimum Normal Force Principle Based Quantitive Optimizationof Clamping Forces for Thin Walled Part
Institute of Scientific and Technical Information of China (English)
ZHANG Fa-ping; SUN Hou-fang; SHAHID I.Butt
2008-01-01
Based on the stability criteria of workpiece-fixture system, quantitative optimization of clamping forces during precise machining process for thin walled part is studied considering the contact condition between wokpiece and locator, the contact mechanical model is achieved ,which is further been used to calculate the entire passive forces acting on the statically undetermined workpiece by means of the force screw theory as well as minimum norm force principle. Furthermore, a new methodology to optimize clamping forces is put forward, on the criteria of keeping the stability of workpiece during cutting process. By this way, the intensity of clamping forces is decreased dramatically, which will be most beneficial for improving the machining quality of thin-walled parts. Finally, a case study is used to support and validate the proposed model.
The ultimate determinants of central bank independence
Eijffinger, S.C.W.; Schaling, E.
1995-01-01
Using a graphical method, a new way of determining the optimal degree of central bank conservativeness is developed in this paper. Unlike Lohmann (1992) and Rogoff (1985), we are able to express the upper and lower bounds of the interval containing the optimal degree of conservativeness in terms of
Betweenness centrality profiles in trees
Fish, Benjamin; Turan, Gyorgy
2016-01-01
Betweenness centrality of a vertex in a graph measures the fraction of shortest paths going through the vertex. This is a basic notion for determining the importance of a vertex in a network. The k-betweenness centrality of a vertex is defined similarly, but only considers shortest paths of length at most k. The sequence of k-betweenness centralities for all possible values of k forms the betweenness centrality profile of a vertex. We study properties of betweenness centrality profiles in trees. We show that for scale-free random trees, for fixed k, the expectation of k-betweenness centrality strictly decreases as the index of the vertex increases. We also analyze worst-case properties of profiles in terms of the distance of profiles from being monotone, and the number of times pairs of profiles can cross. This is related to whether k-betweenness centrality, for small values of k, may be used instead of having to consider all shortest paths. Bounds are given that are optimal in order of magnitude. We also pre...
Modeling of Dynamic Fluid Forces in Fast Switching Valves
DEFF Research Database (Denmark)
Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik Clemmensen;
2015-01-01
force, but these models are computationally expensive and are not suitable for evaluating large numbers of different operation conditions or even design optimization. In the present paper, an effort is done to describe these fluid forces and their origin. An example of the total opposing fluid force...
Force Sensing Resistor and Its Application to Robotic Control①
Institute of Scientific and Technical Information of China (English)
WANGHongrui; LUYingquan; 等
1997-01-01
The force sensing resistor(FSR) and its construction and characteristic are described.By using the optimal electronic interface,the end result which is a direct proportionality between force and voltage is obtained.The circuits of application for force and position measurements in the robotic control are given.The experiment that FSRs are placed on the fingers of BH-1 dexterous hand as tactile sensors to measure the contacting forces shows FSR's force sensitivity is optimized for use in the control of robot contacting with environment.
Optimizing Force Deployment and Force Structure for the Rapid Deployment Force
1984-03-01
this st. wiIl address only air-deployed, air-supported units. Tf close presence, in a crisis , of logistics ships or Marlr Amphibious units is fortuitous...Intnatneater UTE -at-es are generally less than intertheater UTE Rates +or the same aircraft. At the cargo handling ends of the flight route, critica
Institute of Scientific and Technical Information of China (English)
杨银花; 谢云; 吴清; 王玉蓉
2011-01-01
Objective To cany out the hydrolysis for Kushen (Radix Sophorae Flavescentis) by using cellulose to increase the extraction transfer rate and save extraction time of active principles of Kushen. Methods On the foundation of single factor test, three factors, amount of cellulose addition (Xt), pH value of enzymolysis (X2) and time of enzymolysis (X3) , were observed (5 levels being set to each factor) by using central composite design taken the extraction transfer rate of matrine and oxymatrine obtained by HPLC as indexes. The best enzymolysis condition for Kushen was optimized and compared with traditional method. The extraction rate and times were investigated after enzymolysis. Results When the amount of cellulose was 4 U/g, pH was 5. 6 and temperature was 42 Xl, the enzymatic effect of cellulose for Kushen was the best, and extraction transfer rate of matrine and oxymatrine was the highest. With this condition the extraction transfer rate of matrine and oxymatrine was 87. 89% extracting for 15 minutes every time, which increased 7.03 percent and saved time compared with traditional method ( not adding cellulose for 2 hour every time). Conclusion Cellulose can destroy the structure of cell wall of Kushen material, improve the dissolution of active principles, and save the extraction time. It is significant to industry production.%目的 利用纤维素酶对苦参进行水解,以提高苦参有效成分的提取转移率、节省提取时间.方法 在单因素试验基础上,以HPLC测得的苦参碱、氧化苦参碱的提取转移率为指标,采用星点试验设计,对加酶量（X1）、酶解pH（X2）和酶解时间（X3）3个因素（每个因素设5个水平）进行考察,优选苦参最佳酶解条件,并且以水提取方法作为对比,对酶解后的提取速度及次数进行考察.结果酶量为4 U/g、pH为5.6、温度为42℃时,纤维素酶对苦参的酶解效果最好,苦参碱、氧化苦参碱的提取转移率最
Stability of alert survivable forces during reductions
Energy Technology Data Exchange (ETDEWEB)
Canavan, G.H.
1998-01-01
The stability of current and projected strategic forces are discussed within a framework that contains elements of current US and Russian analyses. For current force levels and high alert, stability levels are high, as are the levels of potential strikes, due to the large forces deployed. As force levels drop towards those of current value target sets, the analysis becomes linear, concern shifts from stability to reconstitution, and survivable forces drop out. Adverse marginal costs generally provide disincentives for the reduction of vulnerable weapons, but the exchange of vulnerable for survivable weapons could reduce cost while increasing stability even for aggressive participants. Exchanges between effective vulnerable and survivable missile forces are studied with an aggregated, probabilistic model, which optimizes each sides` first and determines each sides` second strikes and costs by minimizing first strike costs.
Directory of Open Access Journals (Sweden)
L. I. Rozonoer
1999-01-01
Full Text Available Necessary and sufficient conditions for existence of optimal control for all initial data are proved for LQ-optimization problem. If these conditions are fulfilled, necessary and sufficient conditions of optimality are formulated. Basing on the results, some general hypotheses on optimal control in terms of Pontryagin's maximum condition and Bellman's equation are proposed.
Stability of suspended graphene under Casimir force
Chudnovsky, E. M.; Zarzuela, R.
2016-08-01
We consider a graphene sheet suspended above a conducting surface. Treating graphene as an elastic membrane subjected to Casimir force, we study its stability against sagging towards the conductor. There exists a critical elevation at the edges below which the central part of the suspended graphene nucleates a trunk that sinks under the action of the Casimir force. The dependence of the critical elevation on temperature, dimensions, and the elastic stress applied to the graphene sheet is computed.
Institute of Scientific and Technical Information of China (English)
许晓宇; 赵晓慈
2016-01-01
为减小工件装夹变形，提高薄壁件加工精度，以薄壁零件装夹变形最小化为目标函数，通过遗传算法和有限元方法相结合，提出夹紧顺序、装夹布局和夹紧力同步分析方法。用该方法对一航空薄壁零件装夹进行优化分析，优化结果与经验设计及传统分析结果进行对比，有效地降低了工件因装夹不当引起的变形，验证了夹紧顺序、夹具布局和夹紧力同步优化方法的有效性。%In order to minimize the clamping deformation and improve the machining accuracy of thin-walled parts, a synchronous optimization method of clamping sequences, fixture layout and clamping forces was presented with the objective function of minimizing the deformation and through the combination of genetic algorithm and finite element method. An aviation thin-walled work piece was optimized by this method, and compared the optimization results with the experience empirical design and the traditional analysis results. This method can effectively reduce the work piece deformation due to improper clamping and improve the machining accuracy. The result proved the veracity of the synchronous optimization method of clamping sequences, fixture layout and clamping forces.
Stefanescu, Dan Mihai
2011-01-01
Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco
Arzura Idris
2012-01-01
This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysi...
Institute of Scientific and Technical Information of China (English)
王保升; 左健民; 汪木兰
2012-01-01
To obtain an accurate instantaneous milling force model, milling force of element edge is analyzed,and a model is established, Ac cording to the characteristics of end-milling, a method is proposed to judge whether an element milling edge is milling or not, and a specific formula is given.On the basis, an instantaneous milling force model for end-milling is developed including the shear effect and plough effect. Taking into account the PSO algorithm advantages of fast convergence, a coefficient identification method based on the algorithm for milling force is presented.Also ,the implementation steps are given.Milling test results show that the method can identify the milling force coefficient accurately.Predicted values using the proposed instantaneous milling force model are almost the same as measured values.%为获得精确的瞬时铣削力模型,对微元铣削力进行分析,建立了微元铣削力模型.依据立铣加工的特点,提出了微元铣削刃参与铣削的判断方法,给出了具体的计算公式.在此基础上,建立了包含剪切效应和犁入效应的瞬时铣削力模型.利用粒子群算法收敛速度快的优点,提出了基于粒子群的单位铣削力系数辨识方法,给出了算法的实现步骤.铣削试验结果表明,该方法能够精确辨识出单位铣削力系数,利用所提出的瞬时铣削力模型获得的铣削力预测值与铣削力实测值的大小和变化趋势基本一致.
Centralized versus Decentralized Infrastructure Networks
Hines, Paul D H; Schläpfer, Markus
2015-01-01
While many large infrastructure networks, such as power, water, and natural gas systems, have similar physical properties governing flows, these systems tend to have distinctly different sizes and topological structures. This paper seeks to understand how these different size-scales and topological features can emerge from relatively simple design principles. Specifically, we seek to describe the conditions under which it is optimal to build decentralized network infrastructures, such as a microgrid, rather than centralized ones, such as a large high-voltage power system. While our method is simple it is useful in explaining why sometimes, but not always, it is economical to build large, interconnected networks and in other cases it is preferable to use smaller, distributed systems. The results indicate that there is not a single set of infrastructure cost conditions under which optimally-designed networks will have highly centralized architectures. Instead, as costs increase we find that average network size...
Cutaneous mechanisms of isometric ankle force control
DEFF Research Database (Denmark)
Choi, Julia T; Jensen, Jesper Lundbye; Leukel, Christian
2013-01-01
The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force...... of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle...... joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases....
The Trade Off Between Central Bank Independence and Conservativeness
Eijffinger, S.C.W.; Hoeberichts, M.M.
1996-01-01
This paper introduces a parameter for central bank independence in a monetary policy game with a conservative central banker.It tries to explain the optimal degree of central bank independence and conservativeness by four economic and political determinants, both theoretically and empirically.There
Cutaneous mechanisms of isometric ankle force control.
Choi, Julia T; Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo
2013-07-01
The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force output. We used repetitive electrical stimulation of the superficial peroneal (foot dorsum) and medial plantar nerves (foot sole) to disrupt cutaneous afferent input in 8 healthy subjects. We measured the effects of repetitive nerve stimulation on (1) tactile thresholds, (2) performance in an ankle force-matching and (3) an ankle position-matching task. Additional force-matching experiments were done to compare the effects of transient versus continuous stimulation in 6 subjects and to determine the effects of foot anesthesia using lidocaine in another 6 subjects. The results showed that stimulation decreased cutaneous sensory function as evidenced by increased touch threshold. Absolute dorsiflexion force error increased without visual feedback during peroneal nerve stimulation. This was not a general effect of stimulation because force error did not increase during plantar nerve stimulation. The effects of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases.
Optimal control of ratchets without spatial asymmetry
Energy Technology Data Exchange (ETDEWEB)
Chacon, Ricardo [Departamento de Fisica Aplicada, Escuela de IngenierIas Industriales, Universidad de Extremadura, Apartado Postal 382, E-06071 Badajoz (Spain)
2007-06-01
This work presents the following conjecture: to optimally enhance directed transport by symmetry breaking of temporal forces there exists a particular force waveform which allows us to deduce simple scaling laws from a quantitative interpretation of Curie's principle. These scaling laws explain in a general setting previous results for a great diversity of systems subjected to a standard biharmonic force and provide a quantitative criterion to optimize the application of the ratchet effect induced by symmetry breaking of temporal forces. Mathematical arguments justifying this conjecture are discussed. (fast track communication)
Laird, Philip
1992-01-01
We distinguish static and dynamic optimization of programs: whereas static optimization modifies a program before runtime and is based only on its syntactical structure, dynamic optimization is based on the statistical properties of the input source and examples of program execution. Explanation-based generalization is a commonly used dynamic optimization method, but its effectiveness as a speedup-learning method is limited, in part because it fails to separate the learning process from the program transformation process. This paper describes a dynamic optimization technique called a learn-optimize cycle that first uses a learning element to uncover predictable patterns in the program execution and then uses an optimization algorithm to map these patterns into beneficial transformations. The technique has been used successfully for dynamic optimization of pure Prolog.
The Homogeneity of Optimal Sensor Placement Across Multiple Winged Insect Species
Jenkins, Abigail L.
Taking inspiration from biology, control algorithms can be implemented to imitate the naturally occurring control systems present in nature. This research is primarily concerned with insect flight and optimal wing sensor placement. Many winged insects with halteres are equipped with mechanoreceptors termed campaniform sensilla. Although the exact information these receptors provide to the insect's nervous system is unknown, it is thought to have the capability of measuring inertial rotation forces. During flight, when the wing bends, the information measured by the campaniform sensilla is received by the central nervous system, and provides the insect necessary data to control flight. This research compares three insect species - the hawkmoth Manduca sexta, the honeybee Apis mellifera, and the fruit fly Drosophila melanogaster. Using an observability-based sensor placement algorithm, the optimal sensor placement for these three species is determined. Simulations resolve if this optimal sensor placement corresponds to the insect's campaniform sensilla, as well as if placement is homogeneous across species.
Schneider, Johannes J
2007-01-01
This book addresses stochastic optimization procedures in a broad manner. The first part offers an overview of relevant optimization philosophies; the second deals with benchmark problems in depth, by applying a selection of optimization procedures. Written primarily with scientists and students from the physical and engineering sciences in mind, this book addresses a larger community of all who wish to learn about stochastic optimization techniques and how to use them.
Demographic tensions in Central America.
1986-08-01
disproportionately benefits high and middle income groups, thereby widening the already large gap between rich and poor. Average per capita income for the poorest 20% of Central Americans is $90 a year (in 1970 US dollars); over half subsist on an average of $200 a year. Central America's economic crisis is further intensified by the marked increase in the economically active population. Doubling in size from about 2.1 million in 1970 to 4.2 million in 1985, the labor force increasingly pressures an economy already weakened by high unemployment and underemployment. Socioeconomically advanced Costa Rica and Panama are Central America's notable exceptions. Life expectancy at birth and infant mortality rates for these better off countries, e.g., are comparable to those of developed countries. Costa Ricans enjoy the most equitable distributional income of all Central Americans. Panama's income differential is 1 of the widest in the world, but its relative wealth affords more for each of its citizens.
Knudsen forces on microcantilevers
Passian, A.; Wig, A.; Meriaudeau, F.; Ferrell, T. L.; Thundat, T.
2002-11-01
When two surfaces at two different temperatures are separated by a distance comparable to a mean-free path of the molecules of the ambient medium, the surfaces experience Knudsen force. This mechanical force can be important in microelectromechanical systems and in atomic force microscopy. A theoretical discussion of the magnitude of the forces and the conditions where they can be encountered is discussed. A potential application of the Knudsen force in designing a cantilever-based vacuum gauge is discussed.
Real time detecting system for turning force
Yue Xiao Bin
2001-01-01
How to get the real-time value of forces dropped on the tool in the course of processing by piezoelectric sensors is introduced. First, the analog signals of the cutting force were achieved by these sensors, amplified and transferred into digital signals by A/D transferring card. Then real-time software reads the information, put it into its own coordinate, drew the curve of forces, displayed it on the screen by the real time and saved it for the technicians to analyze the situation of the tool. So the cutting parameter can be optimized to improve surface quality of the pieces
Enhancing Army Joint Force Headquarters Capabilities
2010-01-01
Ad hoc (Army) 2004–2005 MNSTC-I SSTR CENTCOM Ad hoc (Army) 2004-2005 JTF-G8/ DNC /RNC HD/CS NORTHCOM Ad hoc (Army) x 3 2004 JTF-515 SSTR PACOM 2004...AFIC = Armed Forces Inaugural Committee; CENTCOM = Central Command; DNC = Democratic National Committee; EUCOM = European Command; FSSG = Fleet
Hirsch index as a network centrality measure
Campiteli, Monica G; Soles, Paulo R C; Soares, Leonardo H D; Kinouchi, Osame
2010-01-01
We study the h Hirsch index as a local node centrality measure for complex networks in general. The h index is compared with the Degree centrality (a local measure), the Betweenness and Eigenvector centralities (two non-local measures) in the case of a biological network (Yeast interaction protein-protein network) and a linguistic network (Moby Thesaurus II) as test environments. In both networks, the Hirsch index has poor correlation with Betweenness centrality but correlates well with Eigenvector centrality, specially for the more important nodes that are relevant for ranking purposes, say in Search Machine Optimization. In the thesaurus network, the h index seems even to outperform the Eigenvector centrality measure as evaluated by simple linguistic criteria.
寺河矿西三盘区集中胶带巷的优化设计%Optimal design of central belt Lane of third pannel in the west of ShiHe coal Mine
Institute of Scientific and Technical Information of China (English)
宋庆阳
2016-01-01
本文通过对巷道开拓方式的选择及设备选型等关键环节论述，介绍西三盘区集中胶带巷设计过程。%The key links of the way of the roadway development and equipment selection were discussed. And the design process of t central belt Lane of third panel were introduced in this paper.
Effective force control by muscle synergies
Directory of Open Access Journals (Sweden)
Denise J Berger
2014-04-01
Full Text Available Muscle synergies have been proposed as a way for the central nervous system (CNS to simplify the generation of motor commands and they have been shown to explain a large fraction of the variation in the muscle patterns across a variety of conditions. However, whether human subjects are able to control forces and movements effectively with a small set of synergies has not been tested directly. Here we show that muscle synergies can be used to generate target forces in multiple directions with the same accuracy achieved using individual muscles. We recorded electromyographic (EMG activity from 13 arm muscles and isometric hand forces during a force reaching task in a virtual environment. From these data we estimated the force associated to each muscle by linear regression and we identified muscle synergies by non-negative matrix factorization. We compared trajectories of a virtual mass displaced by the force estimated using the entire set of recorded EMGs to trajectories obtained using 4 to 5 muscle synergies. While trajectories were similar, when feedback was provided according to force estimated from recorded EMGs (EMG-control on average trajectories generated with the synergies were less accurate. However, when feedback was provided according to recorded force (force-control we did not find significant differences in initial angle error and endpoint error. We then tested whether synergies could be used as effectively as individual muscles to control cursor movement in the force reaching task by providing feedback according to force estimated from the projection of the recorded EMGs into synergy space (synergy-control. Human subjects were able to perform the task immediately after switching from force-control to EMG-control and synergy-control and we found no differences between initial movement direction errors and endpoint errors in all control modes. These results indicate that muscle synergies provide an effective strategy for motor
Institute of Scientific and Technical Information of China (English)
万正喜; 彭高明; 黄志刚
2012-01-01
Aiming at problems of portal frames of bucket-wheel stacker/reclaimer such as poor strength and stiffness, greater material consumptim and existence of safety hazards, detailed force analysis for portal frame is performed, and based on this, a new structure for portal frame is put forward, with jointing race replaced by the annular girder. The new portal frame is of good force-bearing condition and high safety reliability, and saves materials and machining work, so it can provide guidance and reference for design of portal frames of bucket-wheel stacker/reclaimer.%针对传统斗轮堆取料机门座架强度和刚度差、耗材、存在安全隐患等问题,对门座架进行详细受力分析,在此基础上提出了新的门座架结构形式,以环形梁代替联结座圈,新的门座架受力好、节省材料、节省加工工序及加工量、安全可靠性高,可为斗轮堆取料机门座架的设计提供指导和参考.
Paek, Andrew Y; Gailey, Alycia; Parikh, Pranav; Santello, Marco; Contreras-Vidal, Jose
2015-01-01
In this study, we demonstrate the feasibility of predicting hand forces from brain activity recorded with scalp electroencephalography (EEG). Ten able-bodied subjects participated in two tasks: an isometric force production task and a grasp-and-lift task using unconstrained and constrained grasps. We found that EEG electrodes spanning central areas of the scalp were highly correlated to force rate trajectories. Moreover, EEG grand averages in central sites resembled force rate trajectories as opposed to force trajectories. The grasp-and-lift task resulted in higher decoding accuracies than the isometric force production task: across nine subjects, median accuracies for the isometric force production task were r=0.35 whereas median accuracies for unconstrained grasping were r=0.51 and for constrained grasping were r=0.50. Such results could lead to an understanding of the neural representation behind the control of hand forces and could be implemented in the neural control of closed-loop hand-based neuroprostheses.
Optimization of synchronizability in multiplex networks
Dwivedi, Sanjiv K; Jalan, Sarika
2015-01-01
We investigate the optimization of synchronizability in multiplex networks and demonstrate that the interlayer coupling strength is the deciding factor for the efficiency of optimization. The optimized networks have homogeneity in the degree as well as in the betweenness centrality. Additionally, the interlayer coupling strength crucially affects various properties of individual layers in the optimized multiplex networks. We provide an understanding to how the emerged network properties are shaped or affected when the evolution renders them better synchronizable.
Childhood cancer treatment optimization: In rhabdomyosarcoma and supportive care
Schoot, R.A.
2015-01-01
This thesis covers two subjects investigating optimization of cancer cure: prevention and treatment of central venous catheter related complications and improvement of local treatment in head and neck rhabdomyosarcoma survivors. Central venous catheters are indispensable in the modern day treatment
Estonian central bank sees euro as stabilizing force
2006-01-01
Riigikogu rahanduskomisjoni esindajad teatasid, et Eesti Pank on valmistanud ette lisameetmeid tugevdamaks Eesti rahandussektorit ning näeb eurotsooniga liitumises võtit Eesti majanduse stabiilsusele
Singh, Gurinder; Pai, Roopa S
2014-01-01
The objective of the current study is to develop nanoparticles (NPs) drug delivery system of emtricitabine solely using poly(lactic-co-glycolic acid) (PLGA) and evaluate its in vitro and in vivo release performance by systematically optimized HPLC method using Formulation by Design (FbD). NPs were evaluated for in vitro release and in vivo absorption study. The desired chromatographic separation was achieved on a Phenomenex C18 (250 mm × 4.6 mm I.D., 5 μm) column, under isocratic conditions using UV detection at 280 nm. The optimized mobile phase consisted of a mixture of 40 mM phosphate dihydrogen phosphate buffer (pH 6.8), methanol, and 2% acetonitrile in a ratio of (83 : 15 : 2, v/v/v) at a flow rate of 1 mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range 0.040-2.0 μg/mL, with retention time of 4.39 min. An average encapsulation efficiency of 74.34% was obtained for NPs. In vitro studies showed zero-order release and about 95% drug being released within 15 days in PBS (pH 7.4). In conclusion, the proposed optimized method was successfully applied for the determination of in vitro and in vivo release studies of emtricitabine NPs.
The coordinate system for force control.
Saha, Devjani J; Hu, Xiao; Perreault, Eric; Murray, Wendy; Mussa-Ivaldi, Ferdinando A
2015-03-01
The primary objective of this study was to establish the coordinate frame for force control by observing how parameters of force that are not explicitly specified by a motor task vary across the workspace. We asked subjects to apply a force of a specific magnitude with their hand. Subjects could complete the task by applying forces in any direction of their choice in the transverse plane. They were tested with the arm in seven different configurations. To estimate whether contact forces are represented in extrinsic or intrinsic coordinates, we applied the parallel transport method of differential geometry to the net joint torques applied during the task. This approach allowed us to compare the force variability observed at different arm configurations with the force variability that would be expected if the control system were applying an invariant pattern of joint torques at the tested configurations. The results indicate that for the majority of the subjects, the predominant pattern was consistent with an invariant representation in joint coordinates. However, two out of eleven subjects also demonstrated a preference for extrinsic representation. These findings suggest that the central nervous system can represent contact forces in both coordinate frames, with a prevalence toward intrinsic representations.
Institute of Scientific and Technical Information of China (English)
杨景祥; 黄永生; 杜化美
2013-01-01
In this paper, in view of the cost of agricultural planting in fringes of central cities as well as the different, diversified and complex logistics transportation cost in the supply of the agricultural products to the central cities, we proposed the particle swarm optimization model for the agricultural production and logistics supply of these areas. Then through analyzing the characteristics of the agricultural production and logistics supply in these areas, we designed the relevant parameters, established a particle swarm optimization algorithm, and then through a numerical example, tested the effect of the optimization model in the aspects of planting area selection, plant selection and logistics route selection.%针对中心城市周边区域农产品种植成本及供给中心城市物流运输成本的差异性、多样性和复杂性,提出中心城市周边区域农产品生产与物流供应的粒子群优化模型.通过中心城市周边区域农产品生产与物流供应特性为出发点的模型基础分析,设计中心城市周边区域农产品生产和物流供应相关参数,构建粒子群优化模型,并通过算例和算例分析,验证粒子群优化模型在种植区域选择、种植种类选择、物流去向选择方面的优化效果.
Energy Technology Data Exchange (ETDEWEB)
Aslani, Mahmut A.A.; Kuru, Yesim F.; Aslani, Ceren Kutahyali [Ege Univ., Izmir (Turkey). Inst. of Nuclear Sciences
2016-04-01
The interaction between UO{sub 2}{sup 2+} and ammonium-N,N-tetramethylenedithiocarbamate (ATMDTC) was investigated experimentally by means of UV-Vis spectrophotometry. Central Composite Design (CCD) was applied to optimisation of reaction with 54 runs in duplicate. This design type was also used to developed mathematical model equation. Analysis of Variance (ANOVA) indicates that the terms of the model are significant within the 95% confident interval. Remarkably initial solution pH, initial ATMDTC concentration, initial Cu{sup 2+} concentration and temperature have effect on the reaction. Formation constant (log K{sub f}) was calculated as 2.917 by using Rank Annihilation Factor Analysis (RAFA).
2012-01-01
Entre las más recientes aplicaciones del Análisis Probabilista de Seguridad (1997 – 2003) de la Central Nuclear Embalse en Argentina, está el Programa de Mantenimiento Orientado a la Seguridad (2006– 2009) el cual se ha desarrollado con el empleo de la metodología de Mantenimiento Centrado en la Confiabilidad (RCM en inglés). El objetivo general del artículo es demostrar la alta contribución de los fallos mecánicos en el diseño de las políticas de mantenimiento de varios sistemas de la instal...
A handbook for solar central receiver design
Energy Technology Data Exchange (ETDEWEB)
Falcone, P.K.
1986-12-01
This Handbook describes central receiver technology for solar thermal power plants. It contains a description and assessment of the major components in a central receiver system configured for utility scale production of electricity using Rankine-cycle steam turbines. It also describes procedures to size and optimize a plant and discussed examples from recent system analyses. Information concerning site selection criteria, cost estimation, construction, and operation and maintenance is also included, which should enable readers to perform design analyses for specific applications.
Directory of Open Access Journals (Sweden)
Arzura Idris
2012-06-01
Full Text Available This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysia due to “south-south forced migration movements.” These responses are, however, inadequate in terms of commitment to the international refugee regime. While Malaysia did respond to economic and migration challenges, the paper asserts that such efforts are futile if she ignores issues critical to forced migrants.
Ruszczynski, Andrzej
2011-01-01
Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates t
Directory of Open Access Journals (Sweden)
Gurinder Singh
2014-01-01
Full Text Available The objective of the current study is to develop nanoparticles (NPs drug delivery system of emtricitabine solely using poly(lactic-co-glycolic acid (PLGA and evaluate its in vitro and in vivo release performance by systematically optimized HPLC method using Formulation by Design (FbD. NPs were evaluated for in vitro release and in vivo absorption study. The desired chromatographic separation was achieved on a Phenomenex C18 (250 mm × 4.6 mm I.D., 5 μm column, under isocratic conditions using UV detection at 280 nm. The optimized mobile phase consisted of a mixture of 40 mM phosphate dihydrogen phosphate buffer (pH 6.8, methanol, and 2% acetonitrile in a ratio of (83 : 15 : 2, v/v/v at a flow rate of 1 mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range 0.040–2.0 μg/mL, with retention time of 4.39 min. An average encapsulation efficiency of 74.34% was obtained for NPs. In vitro studies showed zero-order release and about 95% drug being released within 15 days in PBS (pH 7.4. In conclusion, the proposed optimized method was successfully applied for the determination of in vitro and in vivo release studies of emtricitabine NPs.
Central bank learning and monetary policy
Tesfaselassie, Mewael F.
2008-01-01
We analyze optimal monetary policy when a central bank has to learn about an unknown coefficient that determines the effect of surprise inflation on aggregate demand. We derive the optimal policy under active learning and compare it to two limiting cases---certainty equivalence policy and cautionary policy, in which learning takes place passively. Our novel result is that the two passive learning policies represent an upper and lower bound for the active learning policy, irrespective of the s...
Knitting Force Measurement on Flat Knitting Machines
Directory of Open Access Journals (Sweden)
A. Fouda
2014-01-01
Full Text Available Knittability can be defined as the ability of yarns to run on knitting machines without problems. Knittability can be achieved when less stress is applied on the knitting machine parts by the knitting yarns. This paper presents a novel measuring system for the knitting force needed to perform knitting yarns on flat knitting machine based on data acquisition system (DAS. The proposed system is used to measure the knitting force at different machine settings and different properties of the knitting yarns to determine the optimal production conditions. For this reason, three types of knitted fabric structures (single jersey, Rib 1 × 1, and full cardigan with three different loop lengths and five different twists of ply yarn were produced. The obtained results showed the optimal yarn ply twist factor (αe which gave minimum knitting force (less stress on needles or knitting yarns at different loop lengths for each structure.
King, Andrew
2008-01-01
Remember when an optimized website was one that merely didn't take all day to appear? Times have changed. Today, website optimization can spell the difference between enterprise success and failure, and it takes a lot more know-how to achieve success. This book is a comprehensive guide to the tips, techniques, secrets, standards, and methods of website optimization. From increasing site traffic to maximizing leads, from revving up responsiveness to increasing navigability, from prospect retention to closing more sales, the world of 21st century website optimization is explored, exemplified a
Directory of Open Access Journals (Sweden)
James W Vaupel
Full Text Available Semelparous organisms have a simple life cycle characterized by immediate death after reproduction. We assume that semelparous life histories can be separated into a juvenile non-reproductive period followed by an adult period during which reproduction is possible. We derive formulae for the optimal age and size at reproduction and for the optimal size of the offspring (e.g., seeds. Our main contribution is to determine the conditions under which the optimal size of the offspring does not depend on the optimal size at reproduction and vice versa.
Hydrophobic Forces in Flotation
Pazhianur, Rajesh R
1999-01-01
An atomic force microscope (AFM) has been used to conduct force measurements to better understand the role of hydrophobic forces in flotation. The force measurements were conducted between a flat mineral substrate and a hydrophobic glass sphere in aqueous solutions. It is assumed that the hydrophobic glass sphere may simulate the behavior of air bubbles during flotation. The results may provide information relevant to the bubble-particle interactions occurring during flotation. The glass ...
Ridgely, Charles T.
2010-01-01
Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…
Debunking Coriolis Force Myths
Shakur, Asif
2014-01-01
Much has been written and debated about the Coriolis force. Unfortunately, this has done little to demystify the paradoxes surrounding this fictitious force invoked by an observer in a rotating frame of reference. It is the purpose of this article to make another valiant attempt to slay the dragon of the Coriolis force! This will be done without…
Martin, Joel R.; Terekhov, Alexander V.; Latash, Mark L.; Zatsiorsky, Vladimir M.
2014-01-01
The neural control of movement has been described using different sets of elemental variables. Two possible sets of elemental variables have been suggested for finger pressing tasks: the forces of individual fingers and the finger commands (also called “finger modes” or “central commands”). In this study we analyze which of the two sets of the elemental variables is more likely used in the optimization of the finger force sharing and which set is used for the stabilization of performance. We used two recently developed techniques – the analytical inverse optimization (ANIO) and the uncontrolled manifold (UCM) analysis – to evaluate each set of elemental variables with respect to both aspects of performance. The results of the UCM analysis favored the finger commands as the elemental variables used for performance stabilization, while ANIO worked equally well on both sets of elemental variables. A simple scheme is suggested as to how the CNS could optimize a cost function dependent on the finger forces, but for the sake of facilitation of the feed-forward control it substitutes the original cost function by a cost function, which is convenient to optimize in the space of finger commands. PMID:23742067
Central bank Financial Independence
J.Ramon Martinez-Resano
2004-01-01
Central bank independence is a multifaceted institutional design. The financial component has been seldom analysed. This paper intends to set a comprehensive conceptual background for central bank financial independence. Quite often central banks are modelled as robot like maximizers of some goal. This perspective neglects the fact that central bank functions are inevitably deployed on its balance sheet and have effects on its income statement. A financially independent central bank exhibits ...
DEFF Research Database (Denmark)
Birkholm, Klavs
2010-01-01
En undersøgelse af anvendelsen af medicin til optimering af koncentration, hukommelse og følelsestonus. Efterfulgt af etiske overvejelser og anbefalinger til det politiske system......En undersøgelse af anvendelsen af medicin til optimering af koncentration, hukommelse og følelsestonus. Efterfulgt af etiske overvejelser og anbefalinger til det politiske system...
DEFF Research Database (Denmark)
A. Kristensen, Anders Schmidt; Damkilde, Lars
2007-01-01
. A way to solve the initial design problem namely finding a form can be solved by so-called topology optimization. The idea is to define a design region and an amount of material. The loads and supports are also fidefined, and the algorithm finds the optimal material distribution. The objective function...... dictates the form, and the designer can choose e.g. maximum stiness, maximum allowable stresses or maximum lowest eigenfrequency. The result of the topology optimization is a relatively coarse map of material layout. This design can be transferred to a CAD system and given the necessary geometrically...... refinements, and then remeshed and reanalysed in other to secure that the design requirements are met correctly. The output of standard topology optimization has seldom well-defined, sharp contours leaving the designer with a tedious interpretation, which often results in less optimal structures. In the paper...
Topology Optimization of Thermal Heat Sinks
DEFF Research Database (Denmark)
Klaas Haertel, Jan Hendrik; Engelbrecht, Kurt; Lazarov, Boyan Stefanov
2015-01-01
in COMSOL Multiphysics. The optimization objective is to minimize the heat sink’s temperature for a prescribed pressure drop and fixed heat generation. To conduct the optimization, COMSOL’s Optimization Module with GCMMA as the optimization method is used. The implementation of this topology optimization...... approach in COMSOL Multiphysics is described in this paper and results for optimized two-dimensional heat sinks are presented. Furthermore, parameter studies regarding the effect of the prescribed pressure drop of the system on Reynolds number and realized heat sink temperature are presented and discussed.......In this paper, topology optimization is applied to optimize the cooling performance of thermal heat sinks. The coupled two-dimensional thermofluid model of a heat sink cooled with forced convection and a density-based topology optimization including density filtering and projection are implemented...
DEFF Research Database (Denmark)
Bialynicki-Birula, I; Cirone, M.A.; Dahl, Jens Peder
2002-01-01
We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii......) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number...... of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force"....
Hernández-Trujillo, Jesús; Cortés-Guzmán, Fernando; Fang, De-Chai; Bader, Richard F W
2007-01-01
Chemistry is determined by the electrostatic forces acting within a collection of nuclei and electrons. The attraction of the nuclei for the electrons is the only attractive force in a molecule and is the force responsible for the bonding between atoms. This is the attractive force acting on the electrons in the Ehrenfest force and on the nuclei in the Feynman force, one that is countered by the repulsion between the electrons in the former and by the repulsion between the nuclei in the latter. The virial theorem relates these forces to the energy changes resulting from interactions between atoms. All bonding, as signified by the presence of a bond path, has a common origin in terms of the mechanics determined by the Ehrenfest, Feynman and virial theorems. This paper is concerned in particular with the mechanics of interaction encountered in what are classically described as 'nonbonded interactions'--are atoms that 'touch' bonded or repelling one another?
Energy Technology Data Exchange (ETDEWEB)
Bialynicki-Birula, I. [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Cirone, M.A.; Straub, F.; Schleich, W.P. [Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Dahl, J.P. [Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Chemical Physics, Dept. of Chemistry, Technical Univ. of Denmark, Lyngby (Denmark); Seligman, T.H. [Centro de Ciencias Fisicas, Univ. of Mexico (UNAM), Cuernavaca (Mexico)
2002-07-01
We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: ''Force without force''. (orig.)
Institute of Scientific and Technical Information of China (English)
周杰; 卓芳; 黄磊; 罗艳
2015-01-01
To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental (CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model (RSM) was set up and the results of the analysis of variance (ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the“trial and error”procedure.
Centralized Allocation in Multiple Markets
DEFF Research Database (Denmark)
Monte, Daniel; Tumennasan, Norovsambuu
The problem of allocating indivisible objects to different agents, where each indi vidual is assigned at most one object, has been widely studied. Pápai (2000) shows that the set of strategy-proof, nonbossy, Pareto optimal and reallocation-proof rules are hierarchical exchange rules | generalizat......The problem of allocating indivisible objects to different agents, where each indi vidual is assigned at most one object, has been widely studied. Pápai (2000) shows that the set of strategy-proof, nonbossy, Pareto optimal and reallocation-proof rules are hierarchical exchange rules...... | generalizations of Gale's Top Trading Cycles mechanism. We study the centralized allocation that takes place in multiple markets. For example, the assignment of multiple types of indivisible objects; or the assignment of objects in successive periods. We show that the set of strategy-proof, Pareto efficient...
Wind Electrolysis: Hydrogen Cost Optimization
Energy Technology Data Exchange (ETDEWEB)
Saur, G.; Ramsden, T.
2011-05-01
This report describes a hydrogen production cost analysis of a collection of optimized central wind based water electrolysis production facilities. The basic modeled wind electrolysis facility includes a number of low temperature electrolyzers and a co-located wind farm encompassing a number of 3MW wind turbines that provide electricity for the electrolyzer units.
Synchrony-optimized power grids
Pinto, Rafael S
2014-01-01
We investigate synchronization in power grids, which we assume to be modeled by a network of Kuramoto oscillators with inertia. More specifically, we study the optimization of the power grid topology to favor the network synchronization. We introduce a rewiring algorithm which consists basically in a hill climb scheme where the edges of the network are swapped in order enhance the main measures of synchronization. As a byproduct of the optimization algorithm, we typically have also the anticipation of the synchronization onset for the optimized network. We perform several robustness tests for the synchrony-optimized power grids, including the impact of consumption peaks. In our analyses, we investigate synthetic random networks, which we consider as hypothetical decentralized power generation situations, and also a network based in the actual power grid of Spain, which corresponds to the current paradigm of centralized power grids. The synchrony-optimized power grids obtained by our algorithm have some intere...
Zare-Dorabei, Rouholah; Ferdowsi, Somayeh Moazen; Barzin, Ahmad; Tadjarodi, Azadeh
2016-09-01
In present work, a graphene oxide chemically modified with 2,2'-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8mg of adsorbent, 20mgL(-1) of each ion at pH 5 and short time of 4min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Qm) of this adsorbent were 369.749, 257.201, 180.893 and 358.824mgg(-1) for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes.
Jamshidi, M.; Ghaedi, M.; Dashtian, K.; Ghaedi, A. M.; Hajati, S.; Goudarzi, A.; Alipanahpour, E.
2016-01-01
In this work, central composite design (CCD) combined with response surface methodology (RSM) and desirability function approach (DFA) gives useful information about operational condition and also to obtain useful information about interaction and main effect of variables concerned to simultaneous ultrasound-assisted removal of brilliant green (BG) and eosin B (EB) by zinc sulfide nanoparticles loaded on activated carbon (ZnS-NPs-AC). Spectra overlap between BG and EB dyes was extensively reduced and/or omitted by derivative spectrophotometric method, while multi-layer artificial neural network (ML-ANN) model learned with Levenberg-Marquardt (LM) algorithm was used for building up a predictive model and prediction of the BG and EB removal. The ANN efficiently was able to forecast the simultaneous BG and EB removal that was confirmed by reasonable numerical value i.e. MSE of 0.0021 and R2 of 0.9589 and MSE of 0.0022 and R2 of 0.9455 for testing data set, respectively. The results reveal acceptable agreement among experimental data and ANN predicted results. Langmuir as the best model for fitting experimental data relevant to BG and EB removal indicates high, economic and profitable adsorption capacity (258.7 and 222.2 mg g- 1) that supports and confirms its applicability for wastewater treatment.
Jamshidi, M; Ghaedi, M; Dashtian, K; Ghaedi, A M; Hajati, S; Goudarzi, A; Alipanahpour, E
2016-01-15
In this work, central composite design (CCD) combined with response surface methodology (RSM) and desirability function approach (DFA) gives useful information about operational condition and also to obtain useful information about interaction and main effect of variables concerned to simultaneous ultrasound-assisted removal of brilliant green (BG) and eosin B (EB) by zinc sulfide nanoparticles loaded on activated carbon (ZnS-NPs-AC). Spectra overlap between BG and EB dyes was extensively reduced and/or omitted by derivative spectrophotometric method, while multi-layer artificial neural network (ML-ANN) model learned with Levenberg-Marquardt (LM) algorithm was used for building up a predictive model and prediction of the BG and EB removal. The ANN efficiently was able to forecast the simultaneous BG and EB removal that was confirmed by reasonable numerical value i.e. MSE of 0.0021 and R(2) of 0.9589 and MSE of 0.0022 and R(2) of 0.9455 for testing data set, respectively. The results reveal acceptable agreement among experimental data and ANN predicted results. Langmuir as the best model for fitting experimental data relevant to BG and EB removal indicates high, economic and profitable adsorption capacity (258.7 and 222.2 mg g(-1)) that supports and confirms its applicability for wastewater treatment.
Sparse regularization for force identification using dictionaries
Qiao, Baijie; Zhang, Xingwu; Wang, Chenxi; Zhang, Hang; Chen, Xuefeng
2016-04-01
The classical function expansion method based on minimizing l2-norm of the response residual employs various basis functions to represent the unknown force. Its difficulty lies in determining the optimum number of basis functions. Considering the sparsity of force in the time domain or in other basis space, we develop a general sparse regularization method based on minimizing l1-norm of the coefficient vector of basis functions. The number of basis functions is adaptively determined by minimizing the number of nonzero components in the coefficient vector during the sparse regularization process. First, according to the profile of the unknown force, the dictionary composed of basis functions is determined. Second, a sparsity convex optimization model for force identification is constructed. Third, given the transfer function and the operational response, Sparse reconstruction by separable approximation (SpaRSA) is developed to solve the sparse regularization problem of force identification. Finally, experiments including identification of impact and harmonic forces are conducted on a cantilever thin plate structure to illustrate the effectiveness and applicability of SpaRSA. Besides the Dirac dictionary, other three sparse dictionaries including Db6 wavelets, Sym4 wavelets and cubic B-spline functions can also accurately identify both the single and double impact forces from highly noisy responses in a sparse representation frame. The discrete cosine functions can also successfully reconstruct the harmonic forces including the sinusoidal, square and triangular forces. Conversely, the traditional Tikhonov regularization method with the L-curve criterion fails to identify both the impact and harmonic forces in these cases.
OPTIMAL THICKNESS OF A CYLINDRICAL SHELL
Directory of Open Access Journals (Sweden)
Paul Ziemann
2015-01-01
Full Text Available In this paper an optimization problem for a cylindrical shell is discussed. The aim is to look for an optimal thickness of a shell to minimize the deformation under an applied external force. As a side condition, the volume of the shell has to stay constant during the optimization process. The deflection is calculated using an approach from shell theory. The resulting control-to-state operator is investigated analytically and a corresponding optimal control problem is formulated. Moreover, necessary conditions for an optimal solution are stated and numerical solutions are presented for different examples.
Institute of Scientific and Technical Information of China (English)
刘丽; 伊奥尔; 乔丹娜; 汤建国; 袁大林; 曹秋娥; 孟昭宇
2013-01-01
为了提高造纸法再造烟叶原料中烟叶碎片的萃取率,以水为溶剂,以萃取时间、萃取温度、液料比进行3因素5水平中心组合设计,采用响应面法优化烟叶碎片萃取参数,建立数学模型,并进行实验验证.结果表明,最优工艺条件为:萃取温度69℃,萃取时间39 min,液料比10.6∶1 (mL∶g);得到了数学预测模型,对最佳工艺条件萃取率的预测值为40.46％,与实测值(40.22％)的相对误差仅为0.59％.%Water as solvent the extraction temperature, extraction time and liquid-solid ratio were opti-mized in order to increase the extraction ratio of tobacco scrap as raw material of paper-making reconstitu-ted tobacco, and the component experiment design with 3 factors and 5 levels were applied. The response surface methodology was applied to optimize the extraction parameters of tobacco scrap, and mathematical model was established and validated. The results showed that;the optimum conditions were:the extraction temperature 69℃,extraction time 39 min,liquid material ratio 10.6:l ;when validation experiments were carried out at these optimum conditions,for 3 times,the average extraction of tobacco stems is 40. 22% , the predicted values of the mathematical model is 40.46% ,the relative error between test values and pre-dicted values was 0. 59% .which was well matched with the predicted content.
1989-11-01
The Central African Republic contains 242,000 square miles, which rolling terrain almost 2000 feet above sea level. The climate is tropical, and it has a population of 2.8 million people with a 2.5% growth rate. There are more than 80 ethnic groups including Baya 34%, Banda 28%, Sara 10%, Mandja 9%, Mboum 9%, and M'Baka 7%. The religions are traditional African 35%, protestant 25%, Roman Catholic 25%, and Muslim 15%, and the languages are French and Sangho. The infant mortality rate is 143/1000, with expectancy at 49 years and a 40% literacy rate. The work force of 1 million is 70% agricultural, industry 6% and commerce and service 6% and government 3%. The government consists of a president assisted by cabinet ministers and a single party. Natural resources include diamonds, uranium, timber, gold, and oil, and major industries are beverages, textiles, and soap. Agricultural products feature coffee, cotton, peanuts, tobacco, food crops and livestock. Most of the population live in rural areas and most of the 80 ethnic groups have their own language. This is one of the world's least developed countries, with a per capita income of $375/year. The main problems with development are the poor transportation infrastructure, and the weak internal and international marketing systems. The US and various international organizations have aided in agriculture development, health programs, and family planning. US investment is mainly in diamond and gold mining, and although oil drilling has been successful it is not economically feasible at current prices.
Airborne Network Optimization with Dynamic Network Update
2015-03-26
AIRBORNE NETWORK OPTIMIZATION WITH DYNAMIC NETWORK UPDATE THESIS Bradly S. Paul, Capt, USAF AFIT-ENG-MS-15-M-030 DEPARTMENT OF THE AIR FORCE AIR...to copyright protection in the United States. AFIT-ENG-MS-15-M-030 AIRBORNE NETWORK OPTIMIZATION WITH DYNAMIC NETWORK UPDATE THESIS Presented to the...NETWORK OPTIMIZATION WITH DYNAMIC NETWORK UPDATE Bradly S. Paul, B.S.C.P. Capt, USAF Committee Membership: Maj Thomas E. Dube Chair Dr. Kenneth M. Hopkinson
Nonlinear Dynamic Force Spectroscopy
Björnham, Oscar
2016-01-01
Dynamic force spectroscopy (DFS) is an experimental technique that is commonly used to assess information of the strength, energy landscape, and lifetime of noncovalent bio-molecular interactions. DFS traditionally requires an applied force that increases linearly with time so that the bio-complex under investigation is exposed to a constant loading rate. However, tethers or polymers can modulate the applied force in a nonlinear regime. For example, bacterial adhesion pili and polymers with worm-like chain properties are examples of structures that show nonlinear force responses. In these situations, the theory for traditional DFS cannot be readily applied. In this work we expand the theory for DFS to also include nonlinear external forces while still maintaining compatibility with the linear DFS theory. To validate the theory we modeled a bio-complex expressed on a stiff, an elastic and a worm-like chain polymer, using Monte Carlo methods, and assessed the corresponding rupture force spectra. It was found th...
U.S. Department of Health & Human Services — The NIDDK Central Repository stores biosamples, genetic and other data collected in designated NIDDK-funded clinical studies. The purpose of the NIDDK Central...
Central Neuropathic Pain Syndromes.
Watson, James C; Sandroni, Paola
2016-03-01
Chronic pain is common in patients with neurologic complications of a central nervous system insult such as stroke. The pain is most commonly musculoskeletal or related to obligatory overuse of neurologically unaffected limbs. However, neuropathic pain can result directly from the central nervous system injury. Impaired sensory discrimination can make it challenging to differentiate central neuropathic pain from other pain types or spasticity. Central neuropathic pain may also begin months to years after the injury, further obscuring recognition of its association with a past neurologic injury. This review focuses on unique clinical features that help distinguish central neuropathic pain. The most common clinical central pain syndromes-central poststroke pain, multiple sclerosis-related pain, and spinal cord injury-related pain-are reviewed in detail. Recent progress in understanding of the pathogenesis of central neuropathic pain is reviewed, and pharmacological, surgical, and neuromodulatory treatments of this notoriously difficult to treat pain syndrome are discussed.
Central venous catheter - flushing
... during cancer treatment Bone marrow transplant - discharge Central venous catheter - dressing change Peripherally inserted central catheter - flushing Sterile technique Surgical wound care - open Review Date 9/22/2016 Updated by: ...
Optimal Control of Isometric Muscle Dynamics
Directory of Open Access Journals (Sweden)
Robert Rockenfeller
2015-03-01
Full Text Available We use an indirect optimal control approach to calculate the optimal neural stimulation needed to obtain measured isometric muscle forces. The neural stimulation of the nerve system is hereby considered to be a control function (input of the system ’muscle’ that solely determines the muscle force (output. We use a well-established muscle model and experimental data of isometric contractions. The model consists of coupled activation and contraction dynamics described by ordinary differential equations. To validate our results, we perform a comparison with commercial optimal control software.
Relativistic Linear Restoring Force
Clark, D.; Franklin, J.; Mann, N.
2012-01-01
We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…
OPTIMAL THICKNESS OF A CYLINDRICAL SHELL - AN OPTIMAL CONTROL PROBLEM IN LINEAR ELASTICITY THEORY
Directory of Open Access Journals (Sweden)
Peter Nestler
2013-01-01
Full Text Available In this paper we discuss optimization problems for cylindrical tubeswhich are loaded by an applied force. This is a problem of optimal control in linear elasticity theory (shape optimization. We are looking for an optimal thickness minimizing the deflection (deformation of the tube under the influence of an external force. From basic equations of mechanics, we derive the equation of deformation. We apply the displacement approach from shell theory and make use of the hypotheses of Mindlin and Reissner. A corresponding optimal control problem is formulated and first order necessary conditions for the optimal solution (optimal thickness are derived. We present numerical examples which were solved by the finite element method.
Intermolecular and surface forces
Israelachvili, Jacob N
2011-01-01
This reference describes the role of various intermolecular and interparticle forces in determining the properties of simple systems such as gases, liquids and solids, with a special focus on more complex colloidal, polymeric and biological systems. The book provides a thorough foundation in theories and concepts of intermolecular forces, allowing researchers and students to recognize which forces are important in any particular system, as well as how to control these forces. This third edition is expanded into three sections and contains five new chapters over the previous edition.· starts fr
Theory of intermolecular forces
Margenau, H; Ter Haar, D
1971-01-01
Theory of Intermolecular Forces deals with the exposition of the principles and techniques of the theory of intermolecular forces. The text focuses on the basic theory and surveys other aspects, with particular attention to relevant experiments. The initial chapters introduce the reader to the history of intermolecular forces. Succeeding chapters present topics on short, intermediate, and long range atomic interactions; properties of Coulomb interactions; shape-dependent forces between molecules; and physical adsorption. The book will be of good use to experts and students of quantum mechanics
Based on the Force Deployment Model of Unascertained Expectation
Directory of Open Access Journals (Sweden)
Jianli Chen
2013-05-01
Full Text Available In this study, we utilize the unascertained mathematics method to give the unascertained number of countermeasure of anti-terrorism strategic force deployment and unknown event. It has been defined the situation sets of force deployment, condition density and mathematical expectation of density model. It has been given the unascertained parameters Cij which decide and direct the force deployment. Find out the condition density matrix of force deployment, further get the conditional density of single target force deployment, using the maximum density mathematical expectation in order to get the optimal mathematical model of multiple target force deployment. Analyzing the coefficient of model and provide two kinds of discussed computing method. The model overcomes the limitation of past deterministic thinking method which study the force deployment and provide the decision maker a relative substantial theory evidence.
Institute of Scientific and Technical Information of China (English)
路海平; 鞠颂东
2012-01-01
社会大物流系统是一个无标度网络,存在明显的集群现象.铁路货运系统作为另一个群体嵌入社会大物流系统,需要在优化网络结构的同时,考虑群体之间的连接和群体内部的连接.基于Barabási-Albert算法的无标度网络生成机制,通过理论推导和实验仿真,分析联合介数中心度及其标准差与网络货流量的关系.研究认为,铁路货运系统节点嵌入社会大物流系统时,应当选择联合介数中心度较大而其标准差较小的节点进行嵌入,通过增加捷径路径可改善中枢节点的连接性,以及减轻和均衡中枢节点的负荷,使得整个物流系统更高效地运作和降低网络优化的成本.%Social logistics system is a scale-free network with obvious group phenomenon. When we study the network structure optimization of railway freight embedded in logistics system, we should not only consider the connection between groups but also the connection within groups. Based on the scale-free network generating mechanism of Barabdsi-Albert (BA) algorithm, we analyze the relationship between joint betweenness centrality together with its standard deviation and network freight flow volume through theoretical deviation and experiment simulation. We draw the conclusion that the junction of railway freight node with other nodes in logistics system should be chosen in the node with higher joint betweenness centrality and lower standard deviation, and the connection of hub node can be improved by increasing shortcut paths. The new optimization algorithm can alleviate and balance the load of hub node, and make the operation of the whole logistics system more efficiently as well as lower the cost for network optimization.
PLA Reforms and Chinas Nuclear Forces
2016-10-01
missiles. Despite much attention paid to its new name and higher organizational status, the Rocket Force appears to be the service least affected...commands and the re- structured Central Military Commission (CMC), however, are staffed by PLAA officers, so the effectiveness of this change remains to...official organizational status remained “one-half notch lower in bureaucratic rank.”10 In official documents, refer- ences to the Second Artillery
Directory of Open Access Journals (Sweden)
Antonio Torres-Valle
2012-05-01
Full Text Available Entre las más recientes aplicaciones del Análisis Probabilista de Seguridad (1997 – 2003 de la Central Nuclear Embalse en Argentina, está el Programa de Mantenimiento Orientado a la Seguridad (2006– 2009 el cual se ha desarrollado con el empleo de la metodología de Mantenimiento Centrado en la Confiabilidad (RCM en inglés. El objetivo general del artículo es demostrar la alta contribución de los fallos mecánicos en el diseño de las políticas de mantenimiento de varios sistemas de la instalación a través del empleo de la metodología RCM. La composición, estructura y políticas de explotación de los sistemas tecnológicos de muchas instalaciones con riesgo asociado, similares a las de los sistemas analizados en este estudio, permite inferir que los resultados que se obtendrán serán equivalentes de aplicarse la metodología RCM en dichas instalaciones. Palabras claves: mantenimiento centrado en la confiabilidad, mantenimiento predictivo, mantenimiento preventivo, fallo mecánico, seguridad, confiabilidad, riesgo.______________________________________________________________________________ Abstract One of the most recent applications of Probabilistic Safety Analysis (1997 – 2003 to Embalse Nuclear Power Plant in Argentina, is the Safety Oriented Maintenance Program (2006 – 2009 developed with employment of the Reliability Centered Maintenance (RCM methodology. The general objective of the paper is to demonstrate the high contribution of the mechanical failures in the maintenance program design through the RCM methodology. The composition, structure and operation strategies of the technological systems of many risk associated facilities, similar to the analysed systems included in this study, allow deduce that the results will equivalent in case of application of RCM methodology in such facilities. Key words: reliability centered maintenance (RCM, predictive maintenance, preventive maintenance, mechanical failure, safety
Institute of Scientific and Technical Information of China (English)
刘欣; 杨新; 张丽; 方振峰; 张涛
2016-01-01
Objective To optimize the extraction process of Scutellariabar bata total alkaloids with central-composite-design response-surface method. Methods Five main factors including ethanol volume fraction ,extraction time ,solid-liquid ratio ,extraction temperature ,and extraction times on this reflux extraction process were investigated ,to screen the influence of various factors on the yield of S. barbata total alkaloid extraction with ultraviolet spectrophotometry. Central composite design was used to design experiments ,and SAS was used to establish a prediction model ,and response surface method was used to abtain the best extraction process. Results The optimal process conditions were 40. 06 times of 55. 20%ethanol reflux extraction under 85℃for two times ,each 113. 29 min. Under the optimal process conditions , the total alkaloid content was 26. 932 9 mg/g , and the deviation of predicted values and measured values were less than 2%. The binomial fitting correlation coefficient was R2=0. 997 5. Conclusion Central-composite-design response-surface methods is successfully used for the optimization on theextraction process of S. barbatatotal alkaloids , with good predictability and stability.%目的：采用星点设计-效应面法优化半枝莲总生物碱回流提取工艺。方法采用紫外分光光度法检测半枝莲总生物碱含量，对乙醇浓度、提取时间、固液比、提取温度、提取次数5个因素进行考察，确定对半枝莲总生物碱提取量影响最大的因素并确定其取值范围，在此基础上进行星点设计实验，SAS软件建立预测模型，采用效应面法优化最佳提取条件。结果确定最优提取工艺条件为温度85℃，40.06倍量55.20%乙醇回流提取2次，每次113.29 min。最佳工艺条件下，测得总生物碱提取量为26.9329 mg/g，实测值与预测值偏差小于2%，二项式拟合的相关系数R2=0.9975。结论采用星点设计-效应面法优化半枝莲总生物碱
Antila, Hanne S; Salonen, Emppu
2013-01-01
This chapter provides an overview of the most common methods for including an explicit description of electronic polarization in molecular mechanics force fields: the induced point dipole, shell, and fluctuating charge models. The importance of including polarization effects in biomolecular simulations is discussed, and some of the most important achievements in the development of polarizable biomolecular force fields to date are highlighted.
DEFF Research Database (Denmark)
Maffiuletti, Nicola A; Aagaard, Per; Blazevich, Anthony J;
2016-01-01
The evaluation of rate of force development during rapid contractions has recently become quite popular for characterising explosive strength of athletes, elderly individuals and patients. The main aims of this narrative review are to describe the neuromuscular determinants of rate of force...
El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N; Dufrêne, Yves F
2015-02-07
In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion ("flocculation") is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.
Elementary Particles and Forces.
Quigg, Chris
1985-01-01
Discusses subatomic particles (quarks, leptons, and others) revealed by higher accelerator energies. A connection between forces at this subatomic level has been established, and prospects are good for a description of forces that encompass binding atomic nuclei. Colors, fundamental interactions, screening, camouflage, electroweak symmetry, and…
Pelvic muscle and acetabular contact forces during gait.
Pedersen, D R; Brand, R A; Davy, D T
1997-09-01
Locations, magnitudes, and directions of pelvic muscle and acetabular contact forces are important to model the effects of abnormal conditions (e.g., deformity, surgery) of the hip accurately. Such data have not been reported previously. We computed the three-dimensional locations of all pelvic muscle and acetabular contact forces during level gait. The approach first required computation of the intersegmental joint resultant forces and moments using limb displacement history, foot-floor forces, and estimated limb inertial properties from one subject. The intersegmental resultant moments were then distributed to the muscles using a 47-element muscle model and a non-linear optimization scheme. Muscle forces were vectorally subtracted from the intersegmental resultants to compute the acetabular contact forces. While the peak joint force magnitudes are similar to those reported previously for the femur, the directions of pelvic contact forces and muscle forces varied considerably over the gait cycle. These variations in contact force directions and three-dimensional forces could be as important as the contact force magnitudes in performing experimental or theoretical studies of loads and stresses in the periacetabular region.
Nanofluids mediating surface forces.
Pilkington, Georgia A; Briscoe, Wuge H
2012-11-01
Fluids containing nanostructures, known as nanofluids, are increasingly found in a wide array of applications due to their unique physical properties as compared with their base fluids and larger colloidal suspensions. With several tuneable parameters such as the size, shape and surface chemistry of nanostructures, as well as numerous base fluids available, nanofluids also offer a new paradigm for mediating surface forces. Other properties such as local surface plasmon resonance and size dependent magnetism of nanostructures also present novel mechanisms for imparting tuneable surface interactions. However, our fundamental understanding, experimentally and theoretically, of how these parameters might affect surface forces remains incomplete. Here we review recent results on equilibrium and dynamic surface forces between macroscopic surfaces in nanofluids, highlighting the overriding trends in the correlation between the physical parameters that characterise nanofluids and the surface forces they mediate. We also discuss the challenges that confront existing surface force knowledge as a result of this new paradigm.
Ekeom, Didace; Hadj Henni, Anis; Cloutier, Guy
2013-03-01
This work demonstrates, with numerical simulations, the potential of an octagonal probe for the generation of radiation forces in a set of points following a path surrounding a breast lesion in the context of dynamic ultrasound elastography imaging. Because of the in-going wave adaptive focusing strategy, the proposed method is adapted to induce shear wave fronts to interact optimally with complex lesions. Transducer elements were based on 1-3 piezocomposite material. Three-dimensional simulations combining the finite element method and boundary element method with periodic boundary conditions in the elevation direction were used to predict acoustic wave radiation in a targeted region of interest. The coupling factor of the piezocomposite material and the radiated power of the transducer were optimized. The transducer's electrical impedance was targeted to 50 Ω. The probe was simulated by assembling the designed transducer elements to build an octagonal phased-array with 256 elements on each edge (for a total of 2048 elements). The central frequency is 4.54 MHz; simulated transducer elements are able to deliver enough power and can generate the radiation force with a relatively low level of voltage excitation. Using dynamic transmitter beamforming techniques, the radiation force along a path and resulting acoustic pattern in the breast were simulated assuming a linear isotropic medium. Magnitude and orientation of the acoustic intensity (radiation force) at any point of a generation path could be controlled for the case of an example representing a heterogeneous medium with an embedded soft mechanical inclusion.
Institute of Scientific and Technical Information of China (English)
侯晓军; 唐菱; 周芃; 张小琼
2016-01-01
Objective:To optimize the base formula of boric acid cream,and investigate its quality. Methods:Using central composite design-response surface methodology,with the viscosity of cream as the index,the amounts of Cremophor A6,Cremophor A25,cetyl alcohol,stearyl alcohol,isooctadecyl isooctadecanoate,jojoba oil and light liquid paraffin were optimized. The appearance characteristics,particle size,viscosity and stability of the preparation and the content of boric acid were studied. Results:The optimal conditions were as follows:50 g Cremophor A6-Cremophor A25(3 ∶2),65 g cetyl alcohol-stearyl alcohol(3∶7),and 125 g isooctadecyl isooctadecanoate-jojoba oil- light liquid paraffin(5 ∶3 ∶2). According to the optimal formula,the cream showed the property of semi-fluid cream,the content of boric acid was 98. 5% of the labeling amount,and the viscosity was about 1. 64 × 104 mPa·s. The predicted value was equivalent to the measured one,and the stability of the preparation was promising. Conclusion:The central composite design-response surface methodology used in the base optimization of boric acid cream is simple with high precision and good predictability,and the quality of the preparation is stable and controllable.%目的：优化硼酸乳膏基质配方，考察制剂成品质量。方法：采用星点设计效应面法，以乳膏黏度为评价指标，优化脂肪醇醚-6（和）硬脂醇、鲸蜡硬脂醇聚醚-25、十六醇、十八醇、异硬脂醇异硬脂酸酯、霍霍巴油、轻质液状石蜡的用量；考察优化后制剂的外观性状、粒度、黏度、稳定性及硼酸的含量。结果：配方中含脂肪醇醚-6-鲸蜡硬脂醇聚醚-25（3∶2）50 g、十六醇-十八醇（3∶7）65 g、异硬脂醇异硬脂酸酯-霍霍巴油-轻质液状石蜡（5∶3∶2）125 g 时，制得的成品为白色半流体乳膏，硼酸含量为标示量的98．50％，粘度为1．64×104 mPa·s，预测值与实测值相当，制剂稳定性较好
Optimal restructuring strategies under various dynamic factors
Institute of Scientific and Technical Information of China (English)
MENG Qing-xuan
2007-01-01
Corporate restructuring was identified as a new industrial force that has great impact on economic values and that therefore has become central in daily financial decision making. This article investigates the optimal restructuring strategies under different dynamic factors and their numerous impacts on firm value. The concept of quasi-leverage is introduced and valuation models are built for corporate debt and equity under imperfect market conditions. The model's input variables include the quasi-leverage and other firm-specific parameters, the output variables include multiple corporate security values. The restructuring cost is formulated in the form of exponential function, which allows us to observe the sensitivity of the variation in security values. The unified model and its analytical solution developed in this research allow us to examine the continuous changes of security values by dynamically changing the coupon rates, riskless interest rate, bankruptcy cost, quasi-leverage, personal tax rate, corporate taxes rate, transaction cost, firm risk, etc., so that the solutions provide useful guidance for financing and restructuring decisions.
DEFF Research Database (Denmark)
Frandsen, P. E.; Jonasson, K.; Nielsen, Hans Bruun
1999-01-01
This lecture note is intended for use in the course 04212 Optimization and Data Fitting at the Technincal University of Denmark. It covers about 25% of the curriculum. Hopefully, the note may be useful also to interested persons not participating in that course. The aim of the note is to give...... an introduction to algorithms for unconstrained optimization. We present Conjugate Gradient, Damped Newton and Quasi Newton methods together with the relevant theoretical background. The reader is assumed to be familiar with algorithms for solving linear and nonlinear system of equations, at a level corresponding...
Adaptive control of force microscope cantilever dynamics
Jensen, S. E.; Dougherty, W. M.; Garbini, J. L.; Sidles, J. A.
2007-09-01
Magnetic resonance force microscopy (MRFM) and other emerging scanning probe microscopies entail the detection of attonewton-scale forces. Requisite force sensitivities are achieved through the use of soft force microscope cantilevers as high resonant-Q micromechanical oscillators. In practice, the dynamics of these oscillators are greatly improved by the application of force feedback control computed in real time by a digital signal processor (DSP). Improvements include increased sensitive bandwidth, reduced oscillator ring up/down time, and reduced cantilever thermal vibration amplitude. However, when the cantilever tip and the sample are in close proximity, electrostatic and Casimir tip-sample force gradients can significantly alter the cantilever resonance frequency, foiling fixed-gain narrow-band control schemes. We report an improved, adaptive control algorithm that uses a Hilbert transform technique to continuously measure the vibration frequency of the thermally-excited cantilever and seamlessly adjust the DSP program coefficients. The closed-loop vibration amplitude is typically 0.05 nm. This adaptive algorithm enables narrow-band formally-optimal control over a wide range of resonance frequencies, and preserves the thermally-limited signal to noise ratio (SNR).
A single magnetic nanocomposite cilia force sensor
Alfadhel, Ahmed
2016-04-20
The advancements in fields like robotics and medicine continuously require improvements of sensor devices and more engagement of cooperative sensing technologies. For example, instruments such as tweezers with sensitive force sensory heads could provide the ability to sense a variety of physical quantities in real time, such as the amount and direction of the force applied or the texture of the gripped object. Force sensors with such abilities could be great solutions toward the development of smart surgical tools. In this work, a unique force sensor that can be integrated at the tips of robotic arms or surgical tools is reported. The force sensor consists of a single bioinspired, permanent magnetic and highly elastic nanocomposite cilia integrated on a magnetic field sensing element. The nanocomposite is prepared from permanent magnetic nanowires incorporated into the highly elastic polydimethylsiloxane. We demonstrate the potential of this concept by performing several experiments to show the performance of the force sensor. The developed sensor element has a 200 μm in diameter single cilium with 1:5 aspect ratio and shows a detection range up to 1 mN with a sensitivity of 1.6 Ω/mN and a resolution of 31 μN. The simple fabrication process of the sensor allows easy optimization of the sensor performance to meet the needs of different applications.
The Total Force Policy and Effective Force
2006-05-31
analysis.” 23 Roald Dahl, Charlie and the Chocolate Factory , (New York: Pequin Books, 1964), 87, 150. Mr. Dahl’s image of the everlasting gobstopper...Office of the Chief, Army Reserve, 1997. Dahl, Roald. Charlie and the Chocolate Factory . Penguin Books: New York, 1964. Feaver, Peter D. Armed Servants...knot24 that must be untied in order to prove relevance as a military force. Of course, we know the end of these ancient and modern stories. Charlie
Analytic central path, sensitivity analysis and parametric linear programming
A.G. Holder; J.F. Sturm; S. Zhang (Shuzhong)
1998-01-01
textabstractIn this paper we consider properties of the central path and the analytic center of the optimal face in the context of parametric linear programming. We first show that if the right-hand side vector of a standard linear program is perturbed, then the analytic center of the optimal face
Central bank conservatism and labor market reform
Jordahl, Henrik; Laséen, Stefan
1999-01-01
How does central bank conservatism affect labor market reform? In this paper we examine the economic forces at work. An increase in conservatism triggers two opposite effects. It reduces the inflation bias of discretionary monetary policy and hence the benefits of a reform. It also increases unemployment variability, which increases the precautionary benefits of a reform. In combination, the two effects produce a u-shaped relation between conservatism and labor market reform. An empirical inv...
Chordal Graphs and Semidefinite Optimization
DEFF Research Database (Denmark)
Vandenberghe, Lieven; Andersen, Martin Skovgaard
2015-01-01
in combinatorial optimization, linear algebra, statistics, signal processing, machine learning, and nonlinear optimization. This survey covers the theory and applications of chordal graphs, with an emphasis on algorithms developed in the literature on sparse Cholesky factorization. These algorithms are formulated......Chordal graphs play a central role in techniques for exploiting sparsity in large semidefinite optimization problems and in related con-vex optimization problems involving sparse positive semidefinite matrices. Chordal graph properties are also fundamental to several classical results...... as recursions on elimination trees, supernodal elimination trees, or clique trees associated with the graph. The best known example is the multifrontal Cholesky factorization algorithm, but similar algorithms can be formulated for a variety of related problems, including the computation of the partial inverse...
Perforation forces of the intact porcine anterior lens capsule.
Ullrich, Franziska; Lussi, Jonas; Felekis, Dimitrios; Michels, Stephan; Petruska, Andrew J; Nelson, Bradley J
2016-09-01
During the first step of cataract surgery, the lens capsule is perforated and a circular hole is created with a sharp instrument, a procedure called capsulorhexis. To develop automated systems that can assist ophthalmologists during capsulorhexis, the forces required must be quantified. This study investigates perforation forces of the central anterior lens capsule in porcine eyes, which are used as a conservative model for the human eye. A micro-mechanical characterisation method is presented that measures capsular bag perforation forces with a high precision positioning and high-resolution force sensing system. The force during perforation of the anterior lens capsule was measured with various sized needles and indentation speeds and is found to be 15-35mN. A bio-mechanical model is identified that describes an exponential correlation between indentation force and depth, indicating strain hardening behaviour of the porcine anterior lens capsule.
Eckmann, B
2008-01-01
At the close of the 1980s, the independent contributions of Yann Brenier, Mike Cullen and John Mather launched a revolution in the venerable field of optimal transport founded by G Monge in the 18th century, which has made breathtaking forays into various other domains of mathematics ever since. The author presents a broad overview of this area.
Combinatorial optimization theory and algorithms
Korte, Bernhard
2002-01-01
Combinatorial optimization is one of the youngest and most active areas of discrete mathematics, and is probably its driving force today. This book describes the most important ideas, theoretical results, and algorithms of this field. It is conceived as an advanced graduate text, and it can also be used as an up-to-date reference work for current research. The book includes the essential fundamentals of graph theory, linear and integer programming, and complexity theory. It covers classical topics in combinatorial optimization as well as very recent ones. The emphasis is on theoretical results and algorithms with provably good performance. Some applications and heuristics are mentioned, too.
Energy Technology Data Exchange (ETDEWEB)
Bell, R.E.; Hartley, D.S.III; Packard, S.L.
1999-05-01
This report documents refined requirements for tools to aid the process of force design in Operations Other Than War (OOTWs). It recommends actions for the creation of one tool and work on other tools relating to mission planning. It also identifies the governmental agencies and commands with interests in each tool, from whom should come the user advisory groups overseeing the respective tool development activities. The understanding of OOTWs and their analytical support requirements has matured to the point where action can be taken in three areas: force design, collaborative analysis, and impact analysis. While the nature of the action and the length of time before complete results can be expected depends on the area, in each case the action should begin immediately. Force design for OOTWs is not a technically difficult process. Like force design for combat operations, it is a process of matching the capabilities of forces against the specified and implied tasks of the operation, considering the constraints of logistics, transport and force availabilities. However, there is a critical difference that restricts the usefulness of combat force design tools for OOTWs: the combat tools are built to infer non-combat capability requirements from combat capability requirements and cannot reverse the direction of the inference, as is required for OOTWs. Recently, OOTWs have played a larger role in force assessment, system effectiveness and tradeoff analysis, and concept and doctrine development and analysis. In the first Quadrennial Defense Review (QDR), each of the Services created its own OOTW force design tool. Unfortunately, the tools address different parts of the problem and do not coordinate the use of competing capabilities. These tools satisfied the immediate requirements of the QDR, but do not provide a long-term cost-effective solution.
Self-assembling peptide nanofiber hydrogels for central nervous system regeneration
Liu, Xi; Pi, Bin; Wang, Hui; Wang, Xiu-Mei
2015-03-01
Central nervous system (CNS) presents a complex regeneration problem due to the inability of central neurons to regenerate correct axonal and dendritic connections. However, recent advances in developmental neurobiology, cell signaling, cell-matrix interaction, and biomaterials technologies have forced a reconsideration of CNS regeneration potentials from the viewpoint of tissue engineering and regenerative medicine. The applications of a novel tissue regeneration-inducing biomaterial and stem cells are thought to be critical for the mission. The use of peptide nanofiber hydrogels in cell therapy and tissue engineering offers promising perspectives for CNS regeneration. Self-assembling peptide undergo a rapid transformation from liquid to gel upon addition of counterions or pH adjustment, directly integrating with the host tissue. The peptide nanofiber hydrogels have mechanical properties that closely match the native central nervous extracellular matrix, which could enhance axonal growth. Such materials can provide an optimal three dimensional microenvironment for encapsulated cells. These materials can also be tailored with bioactive motifs to modulate the wound environment and enhance regeneration. This review intends to detail the recent status of self-assembling peptide nanofiber hydrogels for CNS regeneration.