Mainstreaming Caenorhabditis elegans in experimental evolution.

PubMed

Gray, Jeremy C; Cutter, Asher D

2014-03-07

Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.

A constraint on antigravity of antimatter from precision spectroscopy of simple atoms

NASA Astrophysics Data System (ADS)

Karshenboim, S. G.

2009-10-01

Consideration of antigravity for antiparticles is an attractive target for various experimental projects. There are a number of theoretical arguments against it but it is not quite clear what kind of experimental data and theoretical suggestions are involved. In this paper we present straightforward arguments against a possibility of antigravity based on a few simple theoretical suggestions and some experimental data. The data are: astrophysical data on rotation of the Solar System in respect to the center of our galaxy and precision spectroscopy data on hydrogen and positronium. The theoretical suggestions for the case of absence of the gravitational field are: equality of electron and positron mass and equality of proton and positron charge. We also assume that QED is correct at the level of accuracy where it is clearly confirmed experimentally.

Communication: Simple liquids' high-density viscosity

NASA Astrophysics Data System (ADS)

Costigliola, Lorenzo; Pedersen, Ulf R.; Heyes, David M.; Schrøder, Thomas B.; Dyre, Jeppe C.

2018-02-01

This paper argues that the viscosity of simple fluids at densities above that of the triple point is a specific function of temperature relative to the freezing temperature at the density in question. The proposed viscosity expression, which is arrived at in part by reference to the isomorph theory of systems with hidden scale invariance, describes computer simulations of the Lennard-Jones system as well as argon and methane experimental data and simulation results for an effective-pair-potential model of liquid sodium.

Spin Seebeck effect in a simple ferromagnet near T c: a Ginzburg-Landau approach

NASA Astrophysics Data System (ADS)

Adachi, Hiroto; Yamamoto, Yutaka; Ichioka, Masanori

2018-04-01

A time-dependent Ginzburg-Landau theory is used to examine the longitudinal spin Seebeck effect in a simple ferromagnet in the vicinity of the Curie temperature T c. It is shown analytically that the spin Seebeck effect is proportional to the magnetization near T c, whose result is in line with the previous numerical finding. It is argued that the present result can be tested experimentally using a simple magnetic system such as EuO/Pt or EuS/Pt.

Comparative Actions of Barbiturates Studied by Pollen Grain Germination.

ERIC Educational Resources Information Center

Kordan, Herbert A.; Mumford, Pauline M.

1979-01-01

Describes a simple experimental system whereby the comparative actions of long, medium, and short-acting barbiturates can be demonstrated in a relatively short period of time under optical microscopy using pollen grains as the biological test or assay system. (Author/HM)

Nanopore Current Oscillations: Nonlinear Dynamics on the Nanoscale.

PubMed

Hyland, Brittany; Siwy, Zuzanna S; Martens, Craig C

2015-05-21

In this Letter, we describe theoretical modeling of an experimentally realized nanoscale system that exhibits the general universal behavior of a nonlinear dynamical system. In particular, we consider the description of voltage-induced current fluctuations through a single nanopore from the perspective of nonlinear dynamics. We briefly review the experimental system and its behavior observed and then present a simple phenomenological nonlinear model that reproduces the qualitative behavior of the experimental data. The model consists of a two-dimensional deterministic nonlinear bistable oscillator experiencing both dissipation and random noise. The multidimensionality of the model and the interplay between deterministic and stochastic forces are both required to obtain a qualitatively accurate description of the physical system.

Experimental observation of Lorenz chaos in the Quincke rotor dynamics.

PubMed

Peters, François; Lobry, Laurent; Lemaire, Elisabeth

2005-03-01

In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

Experimental observation of Lorenz chaos in the Quincke rotor dynamics

NASA Astrophysics Data System (ADS)

Peters, François; Lobry, Laurent; Lemaire, Elisabeth

2005-03-01

In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

An easy-to-build remote laboratory with data transfer using the Internet School Experimental System

NASA Astrophysics Data System (ADS)

Schauer, František; Lustig, František; Dvořák, Jiří; Ožvoldová, Miroslava

2008-07-01

The present state of information communication technology makes it possible to devise and run computer-based e-laboratories accessible to any user with a connection to the Internet, equipped with very simple technical means and making full use of web services. Thus, the way is open for a new strategy of physics education with strongly global features, based on experiment and experimentation. We name this strategy integrated e-learning, and remote experiments across the Internet are the foundation for this strategy. We present both pedagogical and technical reasoning for the remote experiments and outline a simple system based on a server-client approach, and on web services and Java applets. We give here an outline of the prospective remote laboratory system with data transfer using the Internet School Experimental System (ISES) as hardware and ISES WEB Control kit as software. This approach enables the simple construction of remote experiments without building any hardware and virtually no programming, using a paste and copy approach with typical prebuilt blocks such as a camera view, controls, graphs, displays, etc. We have set up and operate at present seven experiments, running round the clock, with more than 12 000 connections since 2005. The experiments are widely used in practical teaching of both university and secondary level physics. The recording of the detailed steps the experimentor takes during the measurement enables detailed study of the psychological aspects of running the experiments. The system is ready for a network of universities to start covering the basic set of physics experiments. In conclusion we summarize the results achieved and experiences of using remote experiments built on the ISES hardware system.

Fast, Computer Supported Experimental Determination of Absolute Zero Temperature at School

ERIC Educational Resources Information Center

Bogacz, Bogdan F.; Pedziwiatr, Antoni T.

2014-01-01

A simple and fast experimental method of determining absolute zero temperature is presented. Air gas thermometer coupled with pressure sensor and data acquisition system COACH is applied in a wide range of temperature. By constructing a pressure vs temperature plot for air under constant volume it is possible to obtain--by extrapolation to zero…

Reinforcing Concepts of Transient Heat Conduction and Convection with Simple Experiments and COMSOL Simulations

ERIC Educational Resources Information Center

Mendez, Sergio; AungYong, Lisa

2014-01-01

To help students make the connection between the concepts of heat conduction and convection to real-world phenomenon, we developed a combined experimental and computational module that can be incorporated into lecture or lab courses. The experimental system we present requires materials and apparatus that are readily accessible, and the procedure…

Data Processing System (DPS) software with experimental design, statistical analysis and data mining developed for use in entomological research.

PubMed

Tang, Qi-Yi; Zhang, Chuan-Xi

2013-04-01

A comprehensive but simple-to-use software package called DPS (Data Processing System) has been developed to execute a range of standard numerical analyses and operations used in experimental design, statistics and data mining. This program runs on standard Windows computers. Many of the functions are specific to entomological and other biological research and are not found in standard statistical software. This paper presents applications of DPS to experimental design, statistical analysis and data mining in entomology. © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of Sciences.

Improved perceptual-motor performance measurement system

NASA Technical Reports Server (NTRS)

Parker, J. F., Jr.; Reilly, R. E.

1969-01-01

Battery of tests determines the primary dimensions of perceptual-motor performance. Eighteen basic measures range from simple tests to sophisticated electronic devices. Improved system has one unit for the subject containing test display and response elements, and one for the experimenter where test setups, programming, and scoring are accomplished.

On heart rate variability and autonomic activity in homeostasis and in systemic inflammation.

PubMed

Scheff, Jeremy D; Griffel, Benjamin; Corbett, Siobhan A; Calvano, Steve E; Androulakis, Ioannis P

2014-06-01

Analysis of heart rate variability (HRV) is a promising diagnostic technique due to the noninvasive nature of the measurements involved and established correlations with disease severity, particularly in inflammation-linked disorders. However, the complexities underlying the interpretation of HRV complicate understanding the mechanisms that cause variability. Despite this, such interpretations are often found in literature. In this paper we explored mathematical modeling of the relationship between the autonomic nervous system and the heart, incorporating basic mechanisms such as perturbing mean values of oscillating autonomic activities and saturating signal transduction pathways to explore their impacts on HRV. We focused our analysis on human endotoxemia, a well-established, controlled experimental model of systemic inflammation that provokes changes in HRV representative of acute stress. By contrasting modeling results with published experimental data and analyses, we found that even a simple model linking the autonomic nervous system and the heart confound the interpretation of HRV changes in human endotoxemia. Multiple plausible alternative hypotheses, encoded in a model-based framework, equally reconciled experimental results. In total, our work illustrates how conventional assumptions about the relationships between autonomic activity and frequency-domain HRV metrics break down, even in a simple model. This underscores the need for further experimental work towards unraveling the underlying mechanisms of autonomic dysfunction and HRV changes in systemic inflammation. Understanding the extent of information encoded in HRV signals is critical in appropriately analyzing prior and future studies. Copyright © 2014 Elsevier Inc. All rights reserved.

On heart rate variability and autonomic activity in homeostasis and in systemic inflammation

PubMed Central

Scheff, Jeremy D.; Griffel, Benjamin; Corbett, Siobhan A.; Calvano, Steve E.; Androulakis, Ioannis P.

2014-01-01

Analysis of heart rate variability (HRV) is a promising diagnostic technique due to the noninvasive nature of the measurements involved and established correlations with disease severity, particularly in inflammation-linked disorders. However, the complexities underlying the interpretation of HRV complicate understanding the mechanisms that cause variability. Despite this, such interpretations are often found in literature. In this paper we explored mathematical modeling of the relationship between the autonomic nervous system and the heart, incorporating basic mechanisms such as perturbing mean values of oscillating autonomic activities and saturating signal transduction pathways to explore their impacts on HRV. We focused our analysis on human endotoxemia, a well-established, controlled experimental model of systemic inflammation that provokes changes in HRV representative of acute stress. By contrasting modeling results with published experimental data and analyses, we found that even a simple model linking the autonomic nervous system and the heart confound the interpretation of HRV changes in human endotoxemia. Multiple plausible alternative hypotheses, encoded in a model-based framework, equally reconciled experimental results. In total, our work illustrates how conventional assumptions about the relationships between autonomic activity and frequency-domain HRV metrics break down, even in a simple model. This underscores the need for further experimental work towards unraveling the underlying mechanisms of autonomic dysfunction and HRV changes in systemic inflammation. Understanding the extent of information encoded in HRV signals is critical in appropriately analyzing prior and future studies. PMID:24680646

An Experimental Realization of a Chaos-Based Secure Communication Using Arduino Microcontrollers

PubMed Central

Zapateiro De la Hoz, Mauricio; Vidal, Yolanda

2015-01-01

Security and secrecy are some of the important concerns in the communications world. In the last years, several encryption techniques have been proposed in order to improve the secrecy of the information transmitted. Chaos-based encryption techniques are being widely studied as part of the problem because of the highly unpredictable and random-look nature of the chaotic signals. In this paper we propose a digital-based communication system that uses the logistic map which is a mathematically simple model that is chaotic under certain conditions. The input message signal is modulated using a simple Delta modulator and encrypted using a logistic map. The key signal is also encrypted using the same logistic map with different initial conditions. In the receiver side, the binary-coded message is decrypted using the encrypted key signal that is sent through one of the communication channels. The proposed scheme is experimentally tested using Arduino shields which are simple yet powerful development kits that allows for the implementation of the communication system for testing purposes. PMID:26413563

Shot-Noise Limited Single-Molecule FRET Histograms: Comparison between Theory and Experiments†

PubMed Central

Nir, Eyal; Michalet, Xavier; Hamadani, Kambiz M.; Laurence, Ted A.; Neuhauser, Daniel; Kovchegov, Yevgeniy; Weiss, Shimon

2011-01-01

We describe a simple approach and present a straightforward numerical algorithm to compute the best fit shot-noise limited proximity ratio histogram (PRH) in single-molecule fluorescence resonant energy transfer diffusion experiments. The key ingredient is the use of the experimental burst size distribution, as obtained after burst search through the photon data streams. We show how the use of an alternated laser excitation scheme and a correspondingly optimized burst search algorithm eliminates several potential artifacts affecting the calculation of the best fit shot-noise limited PRH. This algorithm is tested extensively on simulations and simple experimental systems. We find that dsDNA data exhibit a wider PRH than expected from shot noise only and hypothetically account for it by assuming a small Gaussian distribution of distances with an average standard deviation of 1.6 Å. Finally, we briefly mention the results of a future publication and illustrate them with a simple two-state model system (DNA hairpin), for which the kinetic transition rates between the open and closed conformations are extracted. PMID:17078646

Neural Network Models of Simple Mechanical Systems Illustrating the Feasibility of Accelerated Life Testing

NASA Technical Reports Server (NTRS)

Fusaro, Robert L.; Jones, Steven P.; Jansen, Ralph

1996-01-01

A complete evaluation of the tribological characteristics of a given material/mechanical system is a time-consuming operation since the friction and wear process is extremely systems sensitive. As a result, experimental designs (i.e., Latin Square, Taguchi) have been implemented in an attempt to not only reduce the total number of experimental combinations needed to fully characterize a material/mechanical system, but also to acquire life data for a system without having to perform an actual life test. Unfortunately, these experimental designs still require a great deal of experimental testing and the output does not always produce meaningful information. In order to further reduce the amount of experimental testing required, this study employs a computer neural network model to investigate different material/mechanical systems. The work focuses on the modeling of the wear behavior, while showing the feasibility of using neural networks to predict life data. The model is capable of defining which input variables will influence the tribological behavior of the particular material/mechanical system being studied based on the specifications of the overall system.

Inverse dynamics of underactuated mechanical systems: A simple case study and experimental verification

NASA Astrophysics Data System (ADS)

Blajer, W.; Dziewiecki, K.; Kołodziejczyk, K.; Mazur, Z.

2011-05-01

Underactuated systems are featured by fewer control inputs than the degrees-of-freedom, m < n. The determination of an input control strategy that forces such a system to complete a set of m specified motion tasks is a challenging task, and the explicit solution existence is conditioned to differential flatness of the problem. The flatness-based solution denotes that all the 2 n states and m control inputs can be algebraically expressed in terms of the m specified outputs and their time derivatives up to a certain order, which is in practice attainable only for simple systems. In this contribution the problem is posed in a more practical way as a set of index-three differential-algebraic equations, and the solution is obtained numerically. The formulation is then illustrated by a two-degree-of-freedom underactuated system composed of two rotating discs connected by a torsional spring, in which the pre-specified motion of one of the discs is actuated by the torque applied to the other disc, n = 2 and m = 1. Experimental verification of the inverse simulation control methodology is reported.

Recursive computer architecture for VLSI

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

Treleaven, P.C.; Hopkins, R.P.

1982-01-01

A general-purpose computer architecture based on the concept of recursion and suitable for VLSI computer systems built from replicated (lego-like) computing elements is presented. The recursive computer architecture is defined by presenting a program organisation, a machine organisation and an experimental machine implementation oriented to VLSI. The experimental implementation is being restricted to simple, identical microcomputers each containing a memory, a processor and a communications capability. This future generation of lego-like computer systems are termed fifth generation computers by the Japanese. 30 references.

Classroom Demonstrations Of Atmosphere-ocean Dynamics: Baroclinic Instability

NASA Astrophysics Data System (ADS)

Aurnou, Jonathan; Nadiga, B. T.

2008-09-01

Here we will present simple hands-on experimental demonstrations that show how baroclinic instabilities develop in rotating fluid dynamical systems. Such instabilities are found in the Earth's oceans and atmosphere as well as in the atmospheres and oceans of planetary bodies throughout the solar system and beyond. Our inexpensive experimental apparatus consists of a vinyl-record player, a wide shallow pan, and a weighted, dyed block of ice. Most directly, these demonstrations can be used to explain winter-time atmospheric weather patterns observed in Earth's mid-latitudes.

Alocomotino Control Algorithm for Robotic Linkage Systems

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

Dohner, Jeffrey L.

This dissertation describes the development of a control algorithm that transitions a robotic linkage system between stabilized states producing responsive locomotion. The developed algorithm is demonstrated using a simple robotic construction consisting of a few links with actuation and sensing at each joint. Numerical and experimental validation is presented.

Experimental evaluation of expendable supersonic nozzle concepts

NASA Technical Reports Server (NTRS)

Baker, V.; Kwon, O.; Vittal, B.; Berrier, B.; Re, R.

1990-01-01

Exhaust nozzles for expendable supersonic turbojet engine missile propulsion systems are required to be simple, short and compact, in addition to having good broad-range thrust-minus-drag performance. A series of convergent-divergent nozzle scale model configurations were designed and wind tunnel tested for a wide range of free stream Mach numbers and nozzle pressure ratios. The models included fixed geometry and simple variable exit area concepts. The experimental and analytical results show that the fixed geometry configurations tested have inferior off-design thrust-minus-drag performance in the transonic Mach range. A simple variable exit area configuration called the Axi-Quad nozzle, combining features of both axisymmetric and two-dimensional convergent-divergent nozzles, performed well over a broad range of operating conditions. Analytical predictions of the flow pattern as well as overall performance of the nozzles, using a fully viscous, compressible CFD code, compared very well with the test data.

Experimental research control software system

NASA Astrophysics Data System (ADS)

Cohn, I. A.; Kovalenko, A. G.; Vystavkin, A. N.

2014-05-01

A software system, intended for automation of a small scale research, has been developed. The software allows one to control equipment, acquire and process data by means of simple scripts. The main purpose of that development is to increase experiment automation easiness, thus significantly reducing experimental setup automation efforts. In particular, minimal programming skills are required and supervisors have no reviewing troubles. Interactions between scripts and equipment are managed automatically, thus allowing to run multiple scripts simultaneously. Unlike well-known data acquisition commercial software systems, the control is performed by an imperative scripting language. This approach eases complex control and data acquisition algorithms implementation. A modular interface library performs interaction with external interfaces. While most widely used interfaces are already implemented, a simple framework is developed for fast implementations of new software and hardware interfaces. While the software is in continuous development with new features being implemented, it is already used in our laboratory for automation of a helium-3 cryostat control and data acquisition. The software is open source and distributed under Gnu Public License.

Experimental investigation of connection performance for prefabricated timber beam

NASA Astrophysics Data System (ADS)

Lesmana, C.; Suhendi, S.

2017-06-01

This paper presents an investigation of connection performance for a simple supported prefabricated timber beams using Meranti hardwood (Shorea sp.). The good connection is crucial for the proper functioning of the timber structures. The adequate connection condition should be assured to achieve the requirement capacity design and performance of the system. The property of material was tested according to [1]. The proposed design of bolted connections has been evaluated through experimental investigation and compared to the simple supported beam without connection. The results demonstrate the effectiveness of the proposed connection design although the ultimate load of the beam with connection is only half of the beam without connection. The test results obtained the purposed connection should be improved.

Generating self-organizing collective behavior using separation dynamics from experimental data

NASA Astrophysics Data System (ADS)

Dieck Kattas, Graciano; Xu, Xiao-Ke; Small, Michael

2012-09-01

Mathematical models for systems of interacting agents using simple local rules have been proposed and shown to exhibit emergent swarming behavior. Most of these models are constructed by intuition or manual observations of real phenomena, and later tuned or verified to simulate desired dynamics. In contrast to this approach, we propose using a model that attempts to follow an averaged rule of the essential distance-dependent collective behavior of real pigeon flocks, which was abstracted from experimental data. By using a simple model to follow the behavioral tendencies of real data, we show that our model can exhibit a wide range of emergent self-organizing dynamics such as flocking, pattern formation, and counter-rotating vortices.

Generating self-organizing collective behavior using separation dynamics from experimental data.

PubMed

Dieck Kattas, Graciano; Xu, Xiao-Ke; Small, Michael

2012-09-01

Mathematical models for systems of interacting agents using simple local rules have been proposed and shown to exhibit emergent swarming behavior. Most of these models are constructed by intuition or manual observations of real phenomena, and later tuned or verified to simulate desired dynamics. In contrast to this approach, we propose using a model that attempts to follow an averaged rule of the essential distance-dependent collective behavior of real pigeon flocks, which was abstracted from experimental data. By using a simple model to follow the behavioral tendencies of real data, we show that our model can exhibit a wide range of emergent self-organizing dynamics such as flocking, pattern formation, and counter-rotating vortices.

The Ideal Solvent for Paper Chromatography of Food Dyes.

ERIC Educational Resources Information Center

Markow, Peter G.

1988-01-01

Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

Neural-network quantum state tomography

NASA Astrophysics Data System (ADS)

Torlai, Giacomo; Mazzola, Guglielmo; Carrasquilla, Juan; Troyer, Matthias; Melko, Roger; Carleo, Giuseppe

2018-05-01

The experimental realization of increasingly complex synthetic quantum systems calls for the development of general theoretical methods to validate and fully exploit quantum resources. Quantum state tomography (QST) aims to reconstruct the full quantum state from simple measurements, and therefore provides a key tool to obtain reliable analytics1-3. However, exact brute-force approaches to QST place a high demand on computational resources, making them unfeasible for anything except small systems4,5. Here we show how machine learning techniques can be used to perform QST of highly entangled states with more than a hundred qubits, to a high degree of accuracy. We demonstrate that machine learning allows one to reconstruct traditionally challenging many-body quantities—such as the entanglement entropy—from simple, experimentally accessible measurements. This approach can benefit existing and future generations of devices ranging from quantum computers to ultracold-atom quantum simulators6-8.

CamOptimus: a tool for exploiting complex adaptive evolution to optimize experiments and processes in biotechnology.

PubMed

Cankorur-Cetinkaya, Ayca; Dias, Joao M L; Kludas, Jana; Slater, Nigel K H; Rousu, Juho; Oliver, Stephen G; Dikicioglu, Duygu

2017-06-01

Multiple interacting factors affect the performance of engineered biological systems in synthetic biology projects. The complexity of these biological systems means that experimental design should often be treated as a multiparametric optimization problem. However, the available methodologies are either impractical, due to a combinatorial explosion in the number of experiments to be performed, or are inaccessible to most experimentalists due to the lack of publicly available, user-friendly software. Although evolutionary algorithms may be employed as alternative approaches to optimize experimental design, the lack of simple-to-use software again restricts their use to specialist practitioners. In addition, the lack of subsidiary approaches to further investigate critical factors and their interactions prevents the full analysis and exploitation of the biotechnological system. We have addressed these problems and, here, provide a simple-to-use and freely available graphical user interface to empower a broad range of experimental biologists to employ complex evolutionary algorithms to optimize their experimental designs. Our approach exploits a Genetic Algorithm to discover the subspace containing the optimal combination of parameters, and Symbolic Regression to construct a model to evaluate the sensitivity of the experiment to each parameter under investigation. We demonstrate the utility of this method using an example in which the culture conditions for the microbial production of a bioactive human protein are optimized. CamOptimus is available through: (https://doi.org/10.17863/CAM.10257).

Simple refractometer based on in-line fiber interferometers

NASA Astrophysics Data System (ADS)

Esteban, Ó.; Martínez Manuel, R.; Shlyagin, M. G.

2015-09-01

A very simple but accurate optical fiber refractometer based on the Fresnel reflection in the fiber tip and two in-line low-reflective mirrors for light intensity referencing is reported. Each mirror was generated by connecting together 2 fiber sections with FC/PC and FC/APC connectors using the standard FC/PC mating sleeve. For the sensor interrogation, a standard DFB diode laser pumped with a sawtooth-wave current was used. A resolution of 6 x 10-4 was experimentally demonstrated using different liquids. A simple sensor construction and the use of low cost components make the reported system interesting for many applications.

The Study of Damped Harmonic Oscillations Using an Electronic Counter

ERIC Educational Resources Information Center

Wadhwa, Ajay

2009-01-01

We study damped harmonic oscillations in mechanical systems like the loaded spring and simple pendulum with the help of an oscillation measuring electronic counter. The experimental data are used in a software program that solves the differential equation for damped vibrations of any system and determines its position, velocity and acceleration as…

Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system.

PubMed

Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

2014-03-01

Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper.

Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system

NASA Astrophysics Data System (ADS)

Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

2014-03-01

Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper.

Simple Model of a Photoacoustic System as a CR Circuit

ERIC Educational Resources Information Center

Fukuhara, Akiko; Kaneko, Fumitoshi; Ogawa, Naohisa

2012-01-01

We introduce the photoacoustic educational system (PAES), by which we can identify which gas causes the greenhouse effect in a classroom (Kaneko "et al" 2010 "J. Chem. Educ." 87 202-4). PAES is an experimental system in which a pulse of infrared (IR) is absorbed into gas as internal energy, an oscillation of pressure (sound) appears, and then we…

High current proton beams production at Simple Mirror Ion Source 37.

PubMed

Skalyga, V; Izotov, I; Razin, S; Sidorov, A; Golubev, S; Kalvas, T; Koivisto, H; Tarvainen, O

2014-02-01

This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition. Latest experiments at SMIS 37 were performed using a single-aperture two-electrode extraction system. Proton beams with currents up to 450 mA at high voltages below 45 kV were obtained. The maximum beam current density was measured to be 600 mA/cm(2). A possibility of further improvement through the development of an advanced extraction system is discussed.

Measuring complete quantum states with a single observable

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

Peng Xinhua; Suter, Dieter; Du Jiangfeng

2007-10-15

Experimental determination of an unknown quantum state usually requires several incompatible measurements. However, it is also possible to determine the full quantum state from a single, repeated measurement. For this purpose, the quantum system whose state is to be determined is first coupled to a second quantum system (the 'assistant') in such a way that part of the information in the quantum state is transferred to the assistant. The actual measurement is then performed on the enlarged system including the original system and the assistant. We discuss in detail the requirements of this procedure and experimentally implement it on amore » simple quantum system consisting of nuclear spins.« less

Reflection of a polarized light cone

NASA Astrophysics Data System (ADS)

Brody, Jed; Weiss, Daniel; Berland, Keith

2013-01-01

We introduce a visually appealing experimental demonstration of Fresnel reflection. In this simple optical experiment, a polarized light beam travels through a high numerical-aperture microscope objective, reflects off a glass slide, and travels back through the same objective lens. The return beam is sampled with a polarizing beam splitter and produces a surprising geometric pattern on an observation screen. Understanding the origin of this pattern requires careful attention to geometry and an understanding of the Fresnel coefficients for S and P polarized light. We demonstrate that in addition to a relatively simple experimental implementation, the shape of the observed pattern can be computed both analytically and by using optical modeling software. The experience of working through complex mathematical computations and demonstrating their agreement with a surprising experimental observation makes this a highly educational experiment for undergraduate optics or advanced-lab courses. It also provides a straightforward yet non-trivial system for teaching students how to use optical modeling software.

Using entropy measures to characterize human locomotion.

PubMed

Leverick, Graham; Szturm, Tony; Wu, Christine Q

2014-12-01

Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

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

Gavignet, A.A.; Wick, C.J.

In current practice, pressure drops in the mud circulating system and the settling velocity of cuttings are calculated with simple rheological models and simple equations. Wellsite computers now allow more sophistication in drilling computations. In this paper, experimental results on the settling velocity of spheres in drilling fluids are reported, along with rheograms done over a wide range of shear rates. The flow curves are fitted to polynomials and general methods are developed to predict friction losses and settling velocities as functions of the polynomial coefficients. These methods were incorporated in a software package that can handle any rig configurationmore » system, including riser booster. Graphic displays show the effect of each parameter on the performance of the circulating system.« less

Aneesur Rahman Prize Talk

NASA Astrophysics Data System (ADS)

Frenkel, Daan

2007-03-01

During the past decade there has been a unique synergy between theory, experiment and simulation in Soft Matter Physics. In colloid science, computer simulations that started out as studies of highly simplified model systems, have acquired direct experimental relevance because experimental realizations of these simple models can now be synthesized. Whilst many numerical predictions concerning the phase behavior of colloidal systems have been vindicated by experiments, the jury is still out on others. In my talk I will discuss some of the recent technical developments, new findings and open questions in computational soft-matter science.

Closed-loop control of renal perfusion pressure in physiological experiments.

PubMed

Campos-Delgado, D U; Bonilla, I; Rodríguez-Martínez, M; Sánchez-Briones, M E; Ruiz-Hernández, E

2013-07-01

This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).

A real-time camera calibration system based on OpenCV

NASA Astrophysics Data System (ADS)

Zhang, Hui; Wang, Hua; Guo, Huinan; Ren, Long; Zhou, Zuofeng

2015-07-01

Camera calibration is one of the essential steps in the computer vision research. This paper describes a real-time OpenCV based camera calibration system, and developed and implemented in the VS2008 environment. Experimental results prove that the system to achieve a simple and fast camera calibration, compared with MATLAB, higher precision and does not need manual intervention, and can be widely used in various computer vision system.

Cellular Motility--Experiments on Contractile and Motile Mechanisms in the Slime Mould, Physarum Polycephalum

ERIC Educational Resources Information Center

Holmes, R. P.; Stewart, P. R.

1977-01-01

Actin and myosin have now been demonstrated to be important constituents of many eukaryotic cells. Their role is primarily that of a contractile system underlying all aspects of cellular motility. Described here is a simple experimental system to demonstrate quantitatively aspects of motility and its regulation in a slime mold. (Author/MA)

RF-subcarrier-assisted four-state continuous-variable QKD based on coherent detection.

PubMed

Qu, Zhen; Djordjevic, Ivan B; Neifeld, Mark A

2016-12-01

We theoretically investigate and experimentally demonstrate a RF-assisted four-state continuous-variable quantum key distribution (CV-QKD) system. Classical coherent detection is implemented with a simple digital phase noise cancelation scheme. In the proposed system, there is no need for frequency and phase locking between the quantum signals and the local oscillator laser. Moreover, in principle, there is no residual phase noise, and a mean excess noise of 0.0115 (in shot-noise units) can be acquired experimentally. In addition, the minimum transmittance of 0.45 is reached experimentally for secure transmission with commercial photodetectors, and the maximum secret key rate (SKR) of >12  Mbit/s can be obtained. The proposed RF-assisted CV-QKD system opens the door of incorporating microwave photonics into a CV-QKD system and improving the SKR significantly.

Theoretical and Experimental Investigation of Random Gust Loads Part I : Aerodynamic Transfer Function of a Simple Wing Configuration in Incompressible Flow

NASA Technical Reports Server (NTRS)

Hakkinen, Raimo J; Richardson, A S , Jr

1957-01-01

Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

The electrocardiographic Holter monitoring in experimental veterinary practice.

PubMed

Scheer, P; Svoboda, P; Sepsi, M; Janecková, K; Doubek, J

2010-01-01

The long-term electrocardiographic recording with retrospective evaluation (Holter system) has been widely used not only in cardiology, but also in other disciplines of internal medicine and in pharmaceutical research. The Holter system can be used in mini-pig, sheep, dog, cat, rabbit, ferret, and rat. In this paper hardware, software, and anesthesia requirements are summarized with respect to the experimental work with various species. As the Holter systems work in bipolar mode, the use of bipolar leads in sagittal and transversal planes has been proved to be the most appropriate because of large amplitude of QRS complex and uncomplicated consequent automatic analysis of the record. In conclusion, Holter electrocardiography represents a simple and applicable method for monitoring the electrical activity of the heart in small animals' experimental studies.

Directional x-ray dark-field imaging of strongly ordered systems

NASA Astrophysics Data System (ADS)

Jensen, Torben Haugaard; Bech, Martin; Zanette, Irene; Weitkamp, Timm; David, Christian; Deyhle, Hans; Rutishauser, Simon; Reznikova, Elena; Mohr, Jürgen; Feidenhans'L, Robert; Pfeiffer, Franz

2010-12-01

Recently a novel grating based x-ray imaging approach called directional x-ray dark-field imaging was introduced. Directional x-ray dark-field imaging yields information about the local texture of structures smaller than the pixel size of the imaging system. In this work we extend the theoretical description and data processing schemes for directional dark-field imaging to strongly scattering systems, which could not be described previously. We develop a simple scattering model to account for these recent observations and subsequently demonstrate the model using experimental data. The experimental data includes directional dark-field images of polypropylene fibers and a human tooth slice.

Formulation of an experimental substructure model using a Craig-Bampton based transmission simulator

NASA Astrophysics Data System (ADS)

Kammer, Daniel C.; Allen, Mathew S.; Mayes, Randy L.

2015-12-01

Experimental-analytical substructuring is attractive when there is motivation to replace one or more system subcomponents with an experimental model. This experimentally derived substructure can then be coupled to finite element models of the rest of the structure to predict the system response. The transmission simulator method couples a fixture to the component of interest during a vibration test in order to improve the experimental model for the component. The transmission simulator is then subtracted from the tested system to produce the experimental component. The method reduces ill-conditioning by imposing a least squares fit of constraints between substructure modal coordinates to connect substructures, instead of directly connecting physical interface degrees of freedom. This paper presents an alternative means of deriving the experimental substructure model, in which a Craig-Bampton representation of the transmission simulator is created and subtracted from the experimental measurements. The corresponding modal basis of the transmission simulator is described by the fixed-interface modes, rather than free modes that were used in the original approach. These modes do a better job of representing the shape of the transmission simulator as it responds within the experimental system, leading to more accurate results using fewer modes. The new approach is demonstrated using a simple finite element model based example with a redundant interface.

Progress on the Ram Wing Concept with Emphasis on Lateral Dynamics

DOT National Transportation Integrated Search

1971-01-01

Theoretical and experimental efforts conducted at the Transportation Systems Center in the ram wing program are described. Glide Tests were performed using a simple ram wing model operating in an open rectangular trough 50 ft long. Lift drag ratios o...

Orbital Energy Levels in Molecular Hydrogen. A Simple Approach.

ERIC Educational Resources Information Center

Willis, Christopher J.

1988-01-01

Described are the energetics involved in the formation of molecular hydrogen using concepts that should be familiar to students beginning the study of molecular orbital theory. Emphasized are experimental data on ionization energies. Included are two-electron atomic and molecular systems. (CW)

Uranyl(VI) nitrate salts: modeling thermodynamic properties using the binding mean spherical approximation theory and determination of "fictive" binary data.

PubMed

Ruas, Alexandre; Bernard, Olivier; Caniffi, Barbara; Simonin, Jean-Pierre; Turq, Pierre; Blum, Lesser; Moisy, Philippe

2006-02-23

This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 degrees C. A new resolution of the binding mean spherical approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O as a "simple" solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of "simple" solution, values for density and water activity for the binary system UO(2)(NO(3))(2)/H(2)O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary system UO(2)(NO(3))(2)/HNO(3)/H(2)O. This new set of binary data is "fictive" in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown.

Ultrafiltration membrane reactors for enzymatic resolution of amino acids: design model and optimization.

PubMed

Bódalo, A; Gómez, J L.; Gómez, E; Bastida, J; Máximo, M F.; Montiel, M C.

2001-03-08

In this paper the possibility of continuous resolution of DL-phenylalanine, catalyzed by L-aminoacylase in a ultrafiltration membrane reactor (UFMR) is presented. A simple design model, based on previous kinetic studies, has been demonstrated to be capable of describing the behavior of the experimental system. The model has been used to determine the optimal experimental conditions to carry out the asymmetrical hydrolysis of N-acetyl-DL-phenylalanine.

The Influence of Learning Strategies and Performance Strategies upon Engineering Design.

DTIC Science & Technology

1979-09-12

of an intruder alarm system. Subjects were provided with details of-how simple devices function, how detectors could be wired together, etc., and... experimenter , myself. I had the strong impression at that stage (some year or more ago),that many of the inn- ovations were due to the experimenter , even though...accidentally intro- duced. On listening to sample tapes (all sessions were sound recorded and many video recorded) this pessimistic impression is

Optical Interferometric Micrometrology

NASA Technical Reports Server (NTRS)

Abel, Phillip B.; Lauer, James R.

1989-01-01

Resolutions in angstrom and subangstrom range sought for atomic-scale surface probes. Experimental optical micrometrological system built to demonstrate calibration of piezoelectric transducer to displacement sensitivity of few angstroms. Objective to develop relatively simple system producing and measuring translation, across surface of specimen, of stylus in atomic-force or scanning tunneling microscope. Laser interferometer used to calibrate piezoelectric transducer used in atomic-force microscope. Electronic portion of calibration system made of commercially available components.

Analysis of the power flow in nonlinear oscillators driven by random excitation using the first Wiener kernel

NASA Astrophysics Data System (ADS)

Hawes, D. H.; Langley, R. S.

2018-01-01

Random excitation of mechanical systems occurs in a wide variety of structures and, in some applications, calculation of the power dissipated by such a system will be of interest. In this paper, using the Wiener series, a general methodology is developed for calculating the power dissipated by a general nonlinear multi-degree-of freedom oscillatory system excited by random Gaussian base motion of any spectrum. The Wiener series method is most commonly applied to systems with white noise inputs, but can be extended to encompass a general non-white input. From the extended series a simple expression for the power dissipated can be derived in terms of the first term, or kernel, of the series and the spectrum of the input. Calculation of the first kernel can be performed either via numerical simulations or from experimental data and a useful property of the kernel, namely that the integral over its frequency domain representation is proportional to the oscillating mass, is derived. The resulting equations offer a simple conceptual analysis of the power flow in nonlinear randomly excited systems and hence assist the design of any system where power dissipation is a consideration. The results are validated both numerically and experimentally using a base-excited cantilever beam with a nonlinear restoring force produced by magnets.

A systems approach to theoretical fluid mechanics: Fundamentals

NASA Technical Reports Server (NTRS)

Anyiwo, J. C.

1978-01-01

A preliminary application of the underlying principles of the investigator's general system theory to the description and analyses of the fluid flow system is presented. An attempt is made to establish practical models, or elements of the general fluid flow system from the point of view of the general system theory fundamental principles. Results obtained are applied to a simple experimental fluid flow system, as test case, with particular emphasis on the understanding of fluid flow instability, transition and turbulence.

Laboratory Scale Prototype of a Low-Speed Electrodynamic Levitation System Based on a Halbach Magnet Array

ERIC Educational Resources Information Center

Iniguez, J.; Raposo, V.

2009-01-01

In this paper we analyse the behaviour of a small-scale model of a magnetic levitation system based on the Inductrack concept. Drag and lift forces acting on our prototype, moving above a continuous copper track, are studied analytically following a simple low-speed approach. The experimental results are in good agreement with the theoretical…

Modeling sound transmission and reflection in the pulmonary system and chest with application to diagnosis of a collapsed lung

NASA Astrophysics Data System (ADS)

Royston, Thomas J.; Zhang, Xiangling; Mansy, Hussein A.; Sandler, Richard H.

2002-05-01

Experimental studies have shown that a pneumothorax (collapsed lung) substantially alters the propagation of sound introduced at the mouth of an intubated subject and measured at the chest surface. Thus, it is hypothesized that an inexpensive diagnostic procedure could be developed for detection of a pneumothorax based on a simple acoustic test. In the present study, theoretical models of sound transmission through the pulmonary system and chest region are reviewed in the context of their ability to predict acoustic changes caused by a pneumothorax, as well as other pathologic conditions. Such models could aid in parametric design studies to develop acoustic means of diagnosing pneumothorax and other lung pathologies. Extensions of previously developed simple models of the authors are presented that are in more quantitative agreement with experimental results and that simulate both transmission from the bronchial airways to the chest wall, as well as reflection in the bronchial airways. [Research supported by NIH NCRR Grant No. 14250 and NIH NHLBI Grant No. 61108.

Simple and sensitive technique for alignment of the pinhole of a spatial filter of a high-energy, high-power laser system.

PubMed

Sharma, Avnish Kumar; Patidar, Rajesh Kumar; Daiya, Deepak; Joshi, Anandverdhan; Naik, Prasad Anant; Gupta, Parshotam Dass

2013-04-20

In this paper, a new method for alignment of the pinhole of a spatial filter (SF) has been proposed and demonstrated experimentally. The effect of the misalignment of the pinhole on the laser beam profiles has been calculated for circular and elliptical Gaussian laser beams. Theoretical computation has been carried out to illustrate the effect of an intensity mask, placed before the focusing lens of the SF, on the spatial beam profile after the pinhole of the SF. It is shown, both theoretically and experimentally, that a simple intensity mask, consisting of a black dot, can be used to visually align the pinhole with a high accuracy of 5% of the pinhole diameter. The accuracy may be further improved using a computer-based image processing algorithm. Finally, the proposed technique has been demonstrated to align a vacuum SF of a compact 40 J Nd:phosphate glass laser system.

Tuned mass damping system for a pendulum in gravity and microgravity fields

NASA Astrophysics Data System (ADS)

Atour, Farah

2016-07-01

An electrodynamic tether is a simple idea, but one with an amazing number of uses. Electrodynamic tether is a long conductor wire that is attached to the satellite, which can act as a generator or motor, from its motion through the earth's magnetic field. And it has the potential to make space travel significantly cheaper. The lack of electrodynamic tether's widespread in common applications can be attributed to the variable Lorentz forces occuring on the tethers, which will cause them to oscillate and may go out of control, de-orbit the satellite and fall to Earth. A tuned mass damper system, for short refered as tilger, is suggested as damper of oscillations of tethers. A system composed of a tuned mass damper and a simple pendulum simulating the tether was therefore constructed. 350 sets of experimental trials were done on the system, while it was installed inside a drop tower capsule resting on the ground, in order to pick four optimum setup experiments that will undergo a series of microgravity experiments at the Bremen Drop Tower in Bremen, Germany. The GJU Bachelor Research students found that the oscillations of the simple pendulum will not be affected by the tilger during the free fall experiment, except if a feedback mechanism is installed between the simple pendulum and the tilger. In this case, the tilger will dampen the simple pendulum oscillations during free fall.

A Practical Guide to Experimental Geometrical Optics

NASA Astrophysics Data System (ADS)

Garbovskiy, Yuriy A.; Glushchenko, Anatoliy V.

2017-12-01

Preface; 1. Markets of optical materials, components, accessories, light sources and detectors; 2. Introduction to optical experiments: light producing, light managing, light detection and measuring; 3. Light detectors based on semiconductors: photoresistors, photodiodes in a photo-galvanic regime. Principles of operation and measurements; 4. Linear light detectors based on photodiodes; 5. Basic laws of geometrical optics: experimental verification; 6. Converging and diverging thin lenses; 7. Thick lenses; 8. Lens systems; 9. Simple optical instruments I: the eye and the magnifier, eyepieces and telescopes; 10. Simple optical instruments II: light illuminators and microscope; 11. Spherical mirrors; 12. Introduction to optical aberrations; 13. Elements of optical radiometry; 14. Cylindrical lenses and vials; 15. Methods of geometrical optics to measure refractive index; 16. Dispersion of light and prism spectroscope; 17. Elements of computer aided optical design; Index.

Non-invasive heart rate monitoring system using giant magneto resistance sensor.

PubMed

Kalyan, Kubera; Chugh, Vinit Kumar; Anoop, C S

2016-08-01

A simple heart rate (HR) monitoring system designed and developed using the Giant Magneto-Resistance (GMR) sensor is presented in this paper. The GMR sensor is placed on the wrist of the human and it provides the magneto-plethysmographic signal. This signal is processed by the simple analog and digital instrumentation stages to render the heart rate indication. A prototype of the system has been built and test results on 26 volunteers have been reported. The error in HR estimation of the system is merely 1 beat per minute. The performance of the system when layer of cloth is present between the sensor and the human body is investigated. The capability of the system as a HR variability estimator has also been established through experimentation. The proposed technique can be used as an efficient alternative to conventional HR monitors and is well suited for remote and continuous monitoring of HR.

Development of Gravity Acceleration Measurement Using Simple Harmonic Motion Pendulum Method Based on Digital Technology and Photogate Sensor

NASA Astrophysics Data System (ADS)

Yulkifli; Afandi, Zurian; Yohandri

2018-04-01

Development of gravitation acceleration measurement using simple harmonic motion pendulum method, digital technology and photogate sensor has been done. Digital technology is more practical and optimizes the time of experimentation. The pendulum method is a method of calculating the acceleration of gravity using a solid ball that connected to a rope attached to a stative pole. The pendulum is swung at a small angle resulted a simple harmonic motion. The measurement system consists of a power supply, Photogate sensors, Arduino pro mini and seven segments. The Arduino pro mini receives digital data from the photogate sensor and processes the digital data into the timing data of the pendulum oscillation. The calculation result of the pendulum oscillation time is displayed on seven segments. Based on measured data, the accuracy and precision of the experiment system are 98.76% and 99.81%, respectively. Based on experiment data, the system can be operated in physics experiment especially in determination of the gravity acceleration.

Dynamic stability of maglev systems

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

Cai, Y.; Chen, S.S.; Mulcahy, T.M.

1994-05-01

Because dynamic instabilities are not acceptable in any commercial maglev system, it is important to consider dynamic instability in the development of all maglev systems. This study considers the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.

Phase-locked tracking loops for LORAN-C

NASA Technical Reports Server (NTRS)

Burhans, R. W.

1978-01-01

Portable battery operated LORAN-C receivers were fabricated to evaluate simple envelope detector methods with hybrid analog to digital phase locked loop sensor processors. The receivers are used to evaluate LORAN-C in general aviation applications. Complete circuit details are given for the experimental sensor and readout system.

Experimental calibration procedures for rotating Lorentz-force flowmeters

DOE PAGES

Hvasta, M. G.; Slighton, N. T.; Kolemen, E.; ...

2017-07-14

Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. Finally, the calibration processes are explained in a step-by-step manner and compared to experimental results.

Experimental calibration procedures for rotating Lorentz-force flowmeters

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

Hvasta, M. G.; Slighton, N. T.; Kolemen, E.

Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. Finally, the calibration processes are explained in a step-by-step manner and compared to experimental results.

Development of feedforward receptive field structure of a simple cell and its contribution to the orientation selectivity: a modeling study.

PubMed

Garg, Akhil R; Obermayer, Klaus; Bhaumik, Basabi

2005-01-01

Recent experimental studies of hetero-synaptic interactions in various systems have shown the role of signaling in the plasticity, challenging the conventional understanding of Hebb's rule. It has also been found that activity plays a major role in plasticity, with neurotrophins acting as molecular signals translating activity into structural changes. Furthermore, role of synaptic efficacy in biasing the outcome of competition has also been revealed recently. Motivated by these experimental findings we present a model for the development of simple cell receptive field structure based on the competitive hetero-synaptic interactions for neurotrophins combined with cooperative hetero-synaptic interactions in the spatial domain. We find that with proper balance in competition and cooperation, the inputs from two populations (ON/OFF) of LGN cells segregate starting from the homogeneous state. We obtain segregated ON and OFF regions in simple cell receptive field. Our modeling study supports the experimental findings, suggesting the role of synaptic efficacy and the role of spatial signaling. We find that using this model we obtain simple cell RF, even for positively correlated activity of ON/OFF cells. We also compare different mechanism of finding the response of cortical cell and study their possible role in the sharpening of orientation selectivity. We find that degree of selectivity improvement in individual cells varies from case to case depending upon the structure of RF field and type of sharpening mechanism.

Description of operation of fast-response solenoid actuator in diesel fuel system model

NASA Astrophysics Data System (ADS)

Zhao, J.; Grekhov, L. V.; Fan, L.; Ma, X.; Song, E.

2018-03-01

The performance of the fast-response solenoid actuator (FRSA) of engine fuel systems is characterized by the response time of less than 0.1 ms and the necessity to take into consideration the non-stationary peculiarities of mechanical, hydraulic, electrical and magnetic processes. Simple models for magnetization in static and dynamic hysteresis are used for this purpose. The experimental study of the FRSA performance within the electro-hydraulic injector of the Common Rail demonstrated an agreement between the computational and experimental results. The computation of the processes is not only a tool for analysis, but also a tool for design and optimization of the solenoid actuator of new engine fuels systems.

Frequency domain surface EMG sensor fusion for estimating finger forces.

PubMed

Potluri, Chandrasekhar; Kumar, Parmod; Anugolu, Madhavi; Urfer, Alex; Chiu, Steve; Naidu, D; Schoen, Marco P

2010-01-01

Extracting or estimating skeletal hand/finger forces using surface electro myographic (sEMG) signals poses many challenges due to cross-talk, noise, and a temporal and spatially modulated signal characteristics. Normal sEMG measurements are based on single sensor data. In this paper, array sensors are used along with a proposed sensor fusion scheme that result in a simple Multi-Input-Single-Output (MISO) transfer function. Experimental data is used along with system identification to find this MISO system. A Genetic Algorithm (GA) approach is employed to optimize the characteristics of the MISO system. The proposed fusion-based approach is tested experimentally and indicates improvement in finger/hand force estimation.

A System for Measurement of Convection Aboard Space Station

NASA Technical Reports Server (NTRS)

Bogatyrev, Gennady P.; Gorbunov, Aleksei V; Putin, Gennady F.; Ivanov, Alexander I.; Nikitin, Sergei A.; Polezhaev, Vadim I.

1996-01-01

A simple device for direct measurement of buoyancy driven fluid flows in a low-gravity environment is proposed. A system connecting spacecraft accelerometers data and results of thermal convection in enclosure measurements and numerical simulations is developed. This system will permit also to evaluate the low frequency microacceleration component. The goal of the paper is to present objectives and current results of ground-based experimental and numerical modeling of this convection detector.

Design and Experimental Validation of a Simple Controller for a Multi-Segment Magnetic Crawler Robot

DTIC Science & Technology

2015-04-01

Ave, Cambridge, MA USA 02139; bSpace and Naval Warfare (SPAWAR) Systems Center Pacific, San Diego, CA USA 92152 ABSTRACT A novel, multi-segmented...high-level, autonomous control computer. A low-level, embedded microcomputer handles the commands to the driving motors. This paper presents the...to be demonstrated.14 The Unmanned Systems Group at SPAWAR Systems Center Pacific has developed a multi-segment magnetic crawler robot (MSMR

Manipulators with flexible links: A simple model and experiments

NASA Technical Reports Server (NTRS)

Shimoyama, Isao; Oppenheim, Irving J.

1989-01-01

A simple dynamic model proposed for flexible links is briefly reviewed and experimental control results are presented for different flexible systems. A simple dynamic model is useful for rapid prototyping of manipulators and their control systems, for possible application to manipulator design decisions, and for real time computation as might be applied in model based or feedforward control. Such a model is proposed, with the further advantage that clear physical arguments and explanations can be associated with its simplifying features and with its resulting analytical properties. The model is mathematically equivalent to Rayleigh's method. Taking the example of planar bending, the approach originates in its choice of two amplitude variables, typically chosen as the link end rotations referenced to the chord (or the tangent) motion of the link. This particular choice is key in establishing the advantageous features of the model, and it was used to support the series of experiments reported.

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance.

PubMed

Escudero, Jose Antonio; MacLean, R Craig; San Millan, Alvaro

2018-05-02

Multicopy plasmids are extremely abundant in prokaryotes but their role in bacterial evolution remains poorly understood. We recently showed that the increase in gene copy number per cell provided by multicopy plasmids could accelerate the evolution of plasmid-encoded genes. In this work, we present an experimental system to test the ability of multicopy plasmids to promote gene evolution. Using simple molecular biology methods, we constructed a model system where an antibiotic resistance gene can be inserted into Escherichia coli MG1655, either in the chromosome or on a multicopy plasmid. We use an experimental evolution approach to propagate the different strains under increasing concentrations of antibiotics and we measure survival of bacterial populations over time. The choice of the antibiotic molecule and the resistance gene is so that the gene can only confer resistance through the acquisition of mutations. This "evolutionary rescue" approach provides a simple method to test the potential of multicopy plasmids to promote the acquisition of antibiotic resistance. In the next step of the experimental system, the molecular bases of antibiotic resistance are characterized. To identify mutations responsible for the acquisition of antibiotic resistance we use deep DNA sequencing of samples obtained from whole populations and clones. Finally, to confirm the role of the mutations in the gene under study, we reconstruct them in the parental background and test the resistance phenotype of the resulting strains.

Cyclic Fatigue of Brittle Materials with an Indentation-Induced Flaw System

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Salem, Jonathan A.

1996-01-01

The ratio of static to cyclic fatigue life, or 'h ratio', was obtained numerically for an indentation flaw system subjected to sinusoidal loading conditions. Emphasis was placed on developing a simple, quick lifetime prediction tool. The solution for the h ratio was compared with experimental static and cyclic fatigue data obtained from as-indented 96 wt.% alumina specimens tested in room-temperature distilled water.

Experimental setup for precise measurement of losses in high-temperature superconducting transformer

NASA Astrophysics Data System (ADS)

Janu, Z.; Wild, J.; Repa, P.; Jelinek, Z.; Zizek, F.; Peksa, L.; Soukup, F.; Tichy, R.

2006-10-01

A simple cryogenic system for testing of the superconducting power transformer was constructed. Thermal shielding is provided by additional liquid nitrogen bath instead of super-insulation. The system, together with use of a precise nitrogen liquid level meter, permitted calorimetric measurements of losses of the 8 kVA HTS transformer with a resolution of the order of 0.1 W.

The Effects of Swedish Knife Model on Students' Understanding of the Digestive System

ERIC Educational Resources Information Center

Cerrah Ozsevgec, Lale; Artun, Huseyin; Unal, Melike

2012-01-01

This study was designed to examine the effect of Swedish Knife Model on students' understanding of digestive system. A simple experimental design (pretest-treatment-posttest) was used in the study and internal comparison of the results of the one group was made. The sample consisted of 40 7th grade Turkish students whose ages range from 13 to 15.…

Interatomic potential at small internuclear distances. A simple formula for the screening constant

NASA Astrophysics Data System (ADS)

Zinoviev, A. N.

2017-09-01

A simple formula for estimating the screening constant has been proposed. This formula fits well experimental data on the interaction potentials. Quantitative description of the experiment for the effect of electronic screening on the nuclear synthesis reaction cross-section for the D+-D system has been obtained. A conclusion has been made that the differences between the measured cross-sections and their theoretically predicted values, which take place in more complicated cases nuclear synthesis reactions, are not caused by uncertainties in the knowledge of potentials.

Small Oscillations via Conservation of Energy

ERIC Educational Resources Information Center

Troy, Tia; Reiner, Megan; Haugen, Andrew J.; Moore, Nathan T.

2017-01-01

The work describes an analogy-based small oscillations analysis of a standard static equilibrium lab problem. In addition to force analysis, a potential energy function for the system is developed, and by drawing out mathematical similarities to the simple harmonic oscillator, we are able to describe (and experimentally verify) the period of small…

Children's Ability to Comprehend Main Ideas After Reading Expository Prose.

ERIC Educational Resources Information Center

Baumann, James F.

A study was conducted to evaluate children's ability to comprehend main ideas after reading connected discourse and to develop and validate a straightforward and intuitively simple system for identifying main ideas in prose. Three experimental passages were randomly selected from third and sixth grade social studies textbooks, and education…

Complementary Colours for a Physicist

ERIC Educational Resources Information Center

Babic, Vitomir; Cepic, Mojca

2009-01-01

This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing…

An Experimental Approach to Teaching and Learning Elementary Statistical Mechanics

ERIC Educational Resources Information Center

Ellis, Frank B.; Ellis, David C.

2008-01-01

Introductory statistical mechanics is studied for a simple two-state system using an inexpensive and easily built apparatus. A large variety of demonstrations, suitable for students in high school and introductory university chemistry courses, are possible. This article details demonstrations for exothermic and endothermic reactions, the dynamic…

The Use of Chlorella Vulgaris in a Simple Demonstration of Heavy Metal Toxicity.

ERIC Educational Resources Information Center

Gipps, J. F.; Biro, P.

1978-01-01

An experimental system, suitable for secondary schools, uses Chlorella vulgaris to demonstrate the effects of mercury and cadmium. Very low concentrations of mercury or cadmium decrease growth, whereas lead or arsenic have little effect. Further experiments show additive interactions between mercury and cadmium and antagonistic interactions…

A journal bearing with variable geometry for the suppression of vibrations in rotating shafts: Simulation, design, construction and experiment

NASA Astrophysics Data System (ADS)

Chasalevris, Athanasios; Dohnal, Fadi

2015-02-01

The idea for a journal bearing with variable geometry was formerly developed and investigated on its principles of operation giving very optimistic theoretical results for the vibration quenching of simple and more complicated rotor bearing systems during the passage through the first critical speed. The journal bearing with variable geometry is presented in this paper in its final form with the detailed design procedure. The current journal bearing was constructed in order to be applied in a simple real rotor bearing system that already exists as an experimental facility. The current paper presents details on the manufactured prototype bearing as an experimental continuation of previous works that presented the simulation of the operating principle of this journal bearing. The design parameters are discussed thoroughly under the numerical simulation for the fluid film pressure in dependency of the variable fluid film thickness during the operation conditions. The implementation of the variable geometry bearing in an experimental rotor bearing system is outlined. Various measurements highlight the efficiency of the proposed bearing element in vibration quenching during the passage through resonance. The inspiration for the current idea is based on the fact that the alteration of the fluid film characteristics of stiffness and damping during the passage through resonance results in vibration quenching. This alteration of the bearing characteristics is achieved by the introduction of an additional fluid film thickness using the passive displacement of the lower half-bearing part. • The contribution of the current journal bearing in vibration quenching. • Experimental evidence for the VGJB contribution.

Experimental Evaluation of the Free Piston Engine - Linear Alternator (FPLA)

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

Leick, Michael T.; Moses, Ronald W.

2015-03-01

This report describes the experimental evaluation of a prototype free piston engine - linear alternator (FPLA) system developed at Sandia National Laboratories. The opposed piston design wa developed to investigate its potential for use in hybrid electric vehicles (HEVs). The system is mechanically simple with two - stroke uniflow scavenging for gas exchange and timed port fuel injection for fuel delivery, i.e. no complex valving. Electrical power is extracted from piston motion through linear alternators wh ich also provide a means for passive piston synchronization through electromagnetic coupling. In an HEV application, this electrical power would be used to chargemore » the batteries. The engine - alternator system was designed, assembled and operated over a 2 - year period at Sandia National Laboratories in Livermore, CA. This report primarily contains a description of the as - built system, modifications to the system to enable better performance, and experimental results from start - up, motoring, and hydrogen combus tion tests.« less

Analysis of pre-service physics teacher skills designing simple physics experiments based technology

NASA Astrophysics Data System (ADS)

Susilawati; Huda, C.; Kurniawan, W.; Masturi; Khoiri, N.

2018-03-01

Pre-service physics teacher skill in designing simple experiment set is very important in adding understanding of student concept and practicing scientific skill in laboratory. This study describes the skills of physics students in designing simple experiments based technologicall. The experimental design stages include simple tool design and sensor modification. The research method used is descriptive method with the number of research samples 25 students and 5 variations of simple physics experimental design. Based on the results of interviews and observations obtained the results of pre-service physics teacher skill analysis in designing simple experimental physics charged technology is good. Based on observation result, pre-service physics teacher skill in designing simple experiment is good while modification and sensor application are still not good. This suggests that pre-service physics teacher still need a lot of practice and do experiments in designing physics experiments using sensor modifications. Based on the interview result, it is found that students have high enough motivation to perform laboratory activities actively and students have high curiosity to be skilled at making simple practicum tool for physics experiment.

Two-Channel Kondo Effect in a Modified Single Electron Transistor

NASA Astrophysics Data System (ADS)

Oreg, Yuval; Goldhaber-Gordon, David

2003-04-01

We suggest a simple system of two electron droplets which should display two-channel Kondo behavior at experimentally accessible temperatures. Stabilization of the two-channel Kondo fixed point requires fine control of the electrochemical potential in each droplet, which can be achieved by adjusting voltages on nearby gate electrodes. We study the conditions for obtaining this type of two-channel Kondo behavior, discuss the experimentally observable consequences, and explore the gener­alization to the multichannel Kondo case.

The effect of density gradients on hydrometers

NASA Astrophysics Data System (ADS)

Heinonen, Martti; Sillanpää, Sampo

2003-05-01

Hydrometers are simple but effective instruments for measuring the density of liquids. In this work, we studied the effect of non-uniform density of liquid on a hydrometer reading. The effect induced by vertical temperature gradients was investigated theoretically and experimentally. A method for compensating for the effect mathematically was developed and tested with experimental data obtained with the MIKES hydrometer calibration system. In the tests, the method was found reliable. However, the reliability depends on the available information on the hydrometer dimensions and density gradients.

Evaluation of a Proposed Modified F/FB-111 Crew Seat and Restraint System.

DTIC Science & Technology

1981-11-01

each target’s path in the X-Z plane throughout the impact. (See sample plots.) Computing velocities and accelerations was a simple matter in the...until this work unit is retired. The experimental results will eventually be recorded within a permanent data bank at AFAMRL. The sample data plots were... experimental results will eventually be recorded within a permanent data bank at AFAMRL. The sample data plots were selected based on the subject who had the

Formulation of an experimental substructure model using a Craig-Bampton based transmission simulator

DOE PAGES

Kammer, Daniel C.; Allen, Matthew S.; Mayes, Randall L.

2015-09-26

An experimental–analytical substructuring is attractive when there is motivation to replace one or more system subcomponents with an experimental model. This experimentally derived substructure can then be coupled to finite element models of the rest of the structure to predict the system response. The transmission simulator method couples a fixture to the component of interest during a vibration test in order to improve the experimental model for the component. The transmission simulator is then subtracted from the tested system to produce the experimental component. This method reduces ill-conditioning by imposing a least squares fit of constraints between substructure modal coordinatesmore » to connect substructures, instead of directly connecting physical interface degrees of freedom. This paper presents an alternative means of deriving the experimental substructure model, in which a Craig–Bampton representation of the transmission simulator is created and subtracted from the experimental measurements. The corresponding modal basis of the transmission simulator is described by the fixed-interface modes, rather than free modes that were used in the original approach. Moreover, these modes do a better job of representing the shape of the transmission simulator as it responds within the experimental system, leading to more accurate results using fewer modes. The new approach is demonstrated using a simple finite element model based example with a redundant interface.« less

Formulation of an experimental substructure model using a Craig-Bampton based transmission simulator

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

Kammer, Daniel C.; Allen, Matthew S.; Mayes, Randall L.

An experimental–analytical substructuring is attractive when there is motivation to replace one or more system subcomponents with an experimental model. This experimentally derived substructure can then be coupled to finite element models of the rest of the structure to predict the system response. The transmission simulator method couples a fixture to the component of interest during a vibration test in order to improve the experimental model for the component. The transmission simulator is then subtracted from the tested system to produce the experimental component. This method reduces ill-conditioning by imposing a least squares fit of constraints between substructure modal coordinatesmore » to connect substructures, instead of directly connecting physical interface degrees of freedom. This paper presents an alternative means of deriving the experimental substructure model, in which a Craig–Bampton representation of the transmission simulator is created and subtracted from the experimental measurements. The corresponding modal basis of the transmission simulator is described by the fixed-interface modes, rather than free modes that were used in the original approach. Moreover, these modes do a better job of representing the shape of the transmission simulator as it responds within the experimental system, leading to more accurate results using fewer modes. The new approach is demonstrated using a simple finite element model based example with a redundant interface.« less

A new statistical method for transfer coefficient calculations in the framework of the general multiple-compartment model of transport for radionuclides in biological systems.

PubMed

Garcia, F; Arruda-Neto, J D; Manso, M V; Helene, O M; Vanin, V R; Rodriguez, O; Mesa, J; Likhachev, V P; Filho, J W; Deppman, A; Perez, G; Guzman, F; de Camargo, S P

1999-10-01

A new and simple statistical procedure (STATFLUX) for the calculation of transfer coefficients of radionuclide transport to animals and plants is proposed. The method is based on the general multiple-compartment model, which uses a system of linear equations involving geometrical volume considerations. By using experimentally available curves of radionuclide concentrations versus time, for each animal compartment (organs), flow parameters were estimated by employing a least-squares procedure, whose consistency is tested. Some numerical results are presented in order to compare the STATFLUX transfer coefficients with those from other works and experimental data.

Effect of measurement on the ballistic-diffusive transition in turbid media.

PubMed

Glasser, Ziv; Yaroshevsky, Andre; Barak, Bavat; Granot, Er'el; Sternklar, Shmuel

2013-10-01

The dependence of the transition between the ballistic and the diffusive regimes of turbid media on the experimental solid angle of the detection system is analyzed theoretically and experimentally. A simple model is developed which shows the significance of experimental conditions on the location of the ballistic-diffusive transition. It is demonstrated that decreasing the solid angle expands the ballistic regime; however, this benefit is bounded by the initial Gaussian beam diffraction. In addition, choosing the appropriate wavelength according to the model's principles provides another means of expanding the ballistic regime. Consequently, by optimizing the experimental conditions, it should be possible to extract the ballistic image of a tissue with a thickness of 1 cm.

Experimental demonstration of real-time adaptively modulated DDO-OFDM systems with a high spectral efficiency up to 5.76bit/s/Hz transmission over SMF links.

PubMed

Chen, Ming; He, Jing; Tang, Jin; Wu, Xian; Chen, Lin

2014-07-28

In this paper, a FPGAs-based real-time adaptively modulated 256/64/16QAM-encoded base-band OFDM transceiver with a high spectral efficiency up to 5.76bit/s/Hz is successfully developed, and experimentally demonstrated in a simple intensity-modulated direct-detection optical communication system. Experimental results show that it is feasible to transmit a raw signal bit rate of 7.19Gbps adaptively modulated real-time optical OFDM signal over 20km and 50km single mode fibers (SMFs). The performance comparison between real-time and off-line digital signal processing is performed, and the results show that there is a negligible power penalty. In addition, to obtain the best transmission performance, direct-current (DC) bias voltage for MZM and launch power into optical fiber links are explored in the real-time optical OFDM systems.

Laser-self-mixing interferometry for mechatronics applications.

PubMed

Ottonelli, Simona; Dabbicco, Maurizio; De Lucia, Francesco; di Vietro, Michela; Scamarcio, Gaetano

2009-01-01

We report on the development of an all-interferometric optomechatronic sensor for the detection of multi-degrees-of-freedom displacements of a remote target. The prototype system exploits the self-mixing technique and consists only of a laser head, equipped with six laser sources, and a suitably designed reflective target. The feasibility of the system was validated experimentally for both single or multi-degrees-of-freedom measurements, thus demonstrating a simple and inexpensive alternative to costly and bulky existing systems.

Chaotic Dynamics and Application of LCR Oscillators Sharing Common Nonlinearity

NASA Astrophysics Data System (ADS)

Jeevarekha, A.; Paul Asir, M.; Philominathan, P.

2016-06-01

This paper addresses the problem of sharing common nonlinearity among nonautonomous and autonomous oscillators. By choosing a suitable common nonlinear element with the driving point characteristics capable of bringing out chaotic motion in a combined system, we obtain identical chaotic states. The dynamics of the coupled system is explored through numerical and experimental studies. Employing the concept of common nonlinearity, a simple chaotic communication system is modeled and its performance is verified through Multisim simulation.

A self-mixing based ring-type fiber-optic acoustic sensor

NASA Astrophysics Data System (ADS)

Wang, Lutang; Wu, Chunxu; Fang, Nian

2014-07-01

A novel, simple fiber-optic acoustic sensor consisting of a self-mixing effect based laser source and a ring-type interferometer is presented. With weak external optical feedbacks, the acoustic wave signals can be detected by measuring the changes of oscillating frequency of the laser diode, induced by the disturbances of sensing fiber, with the ring-type interferometer. The operation principles of the sensor system are explored in-depth and the experimental researches are carried out. The acoustic wave signals produced by various actions, such as by pencil broken, mental pin free falling and PZT are detected for evaluating the sensing performances of the experimental system. The investigation items include the sensitivity as well as frequency responses of the sensor system. An experiment for the detection of corona discharges is carried out, which occur in a high-voltage environment between two parallel copper electrodes, under different humidity levels. The satisfied experimental results are obtained. These experimental results well prove that our proposed sensing system has very high sensitivity and excellent high frequency responses characteristics in the detections of weak, high-frequency acoustic wave signals.

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

Zheng, Dezhi; Liu, Yixuan, E-mail: xuan61x@163.com; Guo, Zhanshe

A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that themore » lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.« less

Theory and experiment research for ultra-low frequency maglev vibration sensor.

PubMed

Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Zhao, Xiaomeng; Fan, Shangchun

2015-10-01

A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.

Theory and experiment research for ultra-low frequency maglev vibration sensor

NASA Astrophysics Data System (ADS)

Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Zhao, Xiaomeng; Fan, Shangchun

2015-10-01

A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.

Experimental Implementation of a Quantum Optical State Comparison Amplifier

NASA Astrophysics Data System (ADS)

Donaldson, Ross J.; Collins, Robert J.; Eleftheriadou, Electra; Barnett, Stephen M.; Jeffers, John; Buller, Gerald S.

2015-03-01

We present an experimental demonstration of a practical nondeterministic quantum optical amplification scheme that employs two mature technologies, state comparison and photon subtraction, to achieve amplification of known sets of coherent states with high fidelity. The amplifier uses coherent states as a resource rather than single photons, which allows for a relatively simple light source, such as a diode laser, providing an increased rate of amplification. The amplifier is not restricted to low amplitude states. With respect to the two key parameters, fidelity and the amplified state production rate, we demonstrate significant improvements over previous experimental implementations, without the requirement of complex photonic components. Such a system may form the basis of trusted quantum repeaters in nonentanglement-based quantum communications systems with known phase alphabets, such as quantum key distribution or quantum digital signatures.

Flutter suppression for the Active Flexible Wing - Control system design and experimental validation

NASA Technical Reports Server (NTRS)

Waszak, M. R.; Srinathkumar, S.

1992-01-01

The synthesis and experimental validation of a control law for an active flutter suppression system for the Active Flexible Wing wind-tunnel model is presented. The design was accomplished with traditional root locus and Nyquist methods using interactive computer graphics tools and with extensive use of simulation-based analysis. The design approach relied on a fundamental understanding of the flutter mechanism to formulate understanding of the flutter mechanism to formulate a simple control law structure. Experimentally, the flutter suppression controller succeeded in simultaneous suppression of two flutter modes, significantly increasing the flutter dynamic pressure despite errors in the design model. The flutter suppression controller was also successfully operated in combination with a rolling maneuver controller to perform flutter suppression during rapid rolling maneuvers.

Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

NASA Astrophysics Data System (ADS)

Akasaka, Ryo

This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

Simple adaptive sparse representation based classification schemes for EEG based brain-computer interface applications.

PubMed

Shin, Younghak; Lee, Seungchan; Ahn, Minkyu; Cho, Hohyun; Jun, Sung Chan; Lee, Heung-No

2015-11-01

One of the main problems related to electroencephalogram (EEG) based brain-computer interface (BCI) systems is the non-stationarity of the underlying EEG signals. This results in the deterioration of the classification performance during experimental sessions. Therefore, adaptive classification techniques are required for EEG based BCI applications. In this paper, we propose simple adaptive sparse representation based classification (SRC) schemes. Supervised and unsupervised dictionary update techniques for new test data and a dictionary modification method by using the incoherence measure of the training data are investigated. The proposed methods are very simple and additional computation for the re-training of the classifier is not needed. The proposed adaptive SRC schemes are evaluated using two BCI experimental datasets. The proposed methods are assessed by comparing classification results with the conventional SRC and other adaptive classification methods. On the basis of the results, we find that the proposed adaptive schemes show relatively improved classification accuracy as compared to conventional methods without requiring additional computation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Note: a simple experimental arrangement to generate optical vortex beams.

PubMed

Kumar, Dhirendra; Das, Abhijit; Boruah, Bosanta R

2013-02-01

In this Note, we present a simple experimental arrangement to generate optical vortex beams. We have demonstrated how by taking print of an interferogram on a transparent sheet, vortex beams with various topological charges can be generated. Experimental results show that the vortex beam indeed carries the topological charge that is used to compute the interferograms. In addition to being simple and inexpensive, one major advantage of the arrangement is that it makes it possible to generate different vortex beams quickly, unlike using the photographic process to create the holograms.

Linear phase encoding for holographic data storage with a single phase-only spatial light modulator.

PubMed

Nobukawa, Teruyoshi; Nomura, Takanori

2016-04-01

A linear phase encoding is presented for realizing a compact and simple holographic data storage system with a single spatial light modulator (SLM). This encoding method makes it possible to modulate a complex amplitude distribution with a single phase-only SLM in a holographic storage system. In addition, an undesired light due to the imperfection of an SLM can be removed by spatial frequency filtering with a Nyquist aperture. The linear phase encoding is introduced to coaxial holographic data storage. The generation of a signal beam using linear phase encoding is experimentally verified in an interferometer. In a coaxial holographic data storage system, single data recording, shift selectivity, and shift multiplexed recording are experimentally demonstrated.

Dynamic stability of maglev systems

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

Cai, Y.; Chen, S.S.; Mulcahy, T.M.

1992-04-01

Because dynamic instability is not acceptable for any commercial maglev systems, it is important to consider this phenomenon in the development of all maglev systems. This study considers the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments attached to a rotating wheel. The theory and analysis developed in this study identifies basic stability characteristics and future research needs of maglev systems.

Experimental evaluation of dynamic data allocation strategies in a distributed database with changing workloads

NASA Technical Reports Server (NTRS)

Brunstrom, Anna; Leutenegger, Scott T.; Simha, Rahul

1995-01-01

Traditionally, allocation of data in distributed database management systems has been determined by off-line analysis and optimization. This technique works well for static database access patterns, but is often inadequate for frequently changing workloads. In this paper we address how to dynamically reallocate data for partionable distributed databases with changing access patterns. Rather than complicated and expensive optimization algorithms, a simple heuristic is presented and shown, via an implementation study, to improve system throughput by 30 percent in a local area network based system. Based on artificial wide area network delays, we show that dynamic reallocation can improve system throughput by a factor of two and a half for wide area networks. We also show that individual site load must be taken into consideration when reallocating data, and provide a simple policy that incorporates load in the reallocation decision.

Object impedance control for cooperative manipulation - Theory and experimental results

NASA Technical Reports Server (NTRS)

Schneider, Stanley A.; Cannon, Robert H., Jr.

1992-01-01

This paper presents the dynamic control module of the Dynamic and Strategic Control of Cooperating Manipulators (DASCCOM) project at Stanford University's Aerospace Robotics Laboratory. First, the cooperative manipulation problem is analyzed from a systems perspective, and the desirable features of a control system for cooperative manipulation are discussed. Next, a control policy is developed that enforces a controlled impedance not of the individual arm endpoints, but of the manipulated object itself. A parallel implementation for a multiprocessor system is presented. The controller fully compensates for the system dynamics and directly controls the object internal forces. Most importantly, it presents a simple, powerful, intuitive interface to higher level strategic control modules. Experimental results from a dual two-link-arm robotic system are used to compare the object impedance controller with other strategies, both for free-motion slews and environmental contact.

Developing a new experimental system for an undergraduate laboratory exercise to teach theories of visuomotor learning.

PubMed

Kasuga, Shoko; Ushiba, Junichi

2014-01-01

Humans have a flexible motor ability to adapt their movements to changes in the internal/external environment. For example, using arm-reaching tasks, a number of studies experimentally showed that participants adapt to a novel visuomotor environment. These results helped develop computational models of motor learning implemented in the central nervous system. Despite the importance of such experimental paradigms for exploring the mechanisms of motor learning, because of the cost and preparation time, most students are unable to participate in such experiments. Therefore, in the current study, to help students better understand motor learning theories, we developed a simple finger-reaching experimental system using commonly used laptop PC components with an open-source programming language (Processing Motor Learning Toolkit: PMLT). We found that compared to a commercially available robotic arm-reaching device, our PMLT accomplished similar learning goals (difference in the error reduction between the devices, P = 0.10). In addition, consistent with previous reports from visuomotor learning studies, the participants showed after-effects indicating an adaptation of the motor learning system. The results suggest that PMLT can serve as a new experimental system for an undergraduate laboratory exercise of motor learning theories with minimal time and cost for instructors.

THz Discrimination of Materials: Development of an Apparatus Based on Room Temperature Detection and Metasurfaces Selective Filters

NASA Astrophysics Data System (ADS)

Carelli, P.; Chiarello, F.; Torrioli, G.; Castellano, M. G.

2017-03-01

We present an apparatus for terahertz discrimination of materials designed to be fast, simple, compact, and economical in order to be suitable for preliminary on-field analysis. The system working principles, bio-inspired by the human vision of colors, are based on the use of an incoherent source, a room temperature detector, a series of microfabricated metamaterials selective filters, a very compact optics based on metallic ellipsoidal mirrors in air, and a treatment of the mirrors' surfaces that select the frequency band of interest. We experimentally demonstrate the operation of the apparatus in discriminating simple substances such as salt, staple foods, and grease. We present the system and the obtained results and discuss issues and possible developments.

Development and demonstration of flueric sounding rocket motor ignition

NASA Technical Reports Server (NTRS)

Marchese, V. P.

1974-01-01

An analytical and experimental program is described which established a flueric rocket motor ignition system concept incorporating a pneumatic match with a simple hand pump as the only energy source. An evaluation was made of this concept to determine the margins of the operating range and capabilities of every component of the system. This evaluation included a determination of power supply requirements, ignitor geometry and alinement, ignitor/propellant interfacing and materials and the effects of ambient temperatures and pressure. It was demonstrated that an operator using a simple hand pump for 30 seconds could ignite BKNO3 at a standoff distance of 100 m (330 ft) with the only connection to the ignitor being a piece of plastic pneumatic tubing.

Active Tailoring of Lift Distribution to Enhance Cruise Performance

NASA Technical Reports Server (NTRS)

Flamm, Jeffrey D. (Technical Monitor); Pfeiffer, Neal J.; Christians, Joel G.

2005-01-01

During Phase I of this project, Raytheon Aircraft Company (RAC) has analytically and experimentally evaluated key components of a system that could be implemented for active tailoring of wing lift distribution using low-drag, trailing-edge modifications. Simple systems such as those studied by RAC could be used to enhance the cruise performance of a business jet configuration over a range of typical flight conditions. The trailing-edge modifications focus on simple, deployable mechanisms comprised of extendable small flap panels over portions of the span that could be used to subtly but positively optimize the lift and drag characteristics. The report includes results from low speed wind tunnel testing of the trailing-edge devices, descriptions of potential mechanisms for automation, and an assessment of the technology.

Predation of Notiophilus (Coleoptera: Carabidae) on Collembola as a Predator-Prey Teaching Model.

ERIC Educational Resources Information Center

Higgins, R. C.

1982-01-01

The carabid beetle (Notiophilus) preys readily on an easily-cultured collembolan in simple experimental conditions. Some features of this predator-prey system are outlined to emphasize its use in biology instruction. Experiments with another potential collembolan are described in the context of developing the method for more advanced studies.…

In Vivo Effects of Barbituates on Seed Germination and Seedling Growth.

ERIC Educational Resources Information Center

Kordan, H. A.

1984-01-01

A simple, low-cost experimental system can be used to demonstrate the "in vivo" effects of barbituates on seed germination and seedling growth behavior in different plant species. Lipid solubility and concentration of individual barbituates both affect the response. List of materials needed, procedures used, and typical results obtained are…

Ensemble Classifier Strategy Based on Transient Feature Fusion in Electronic Nose

NASA Astrophysics Data System (ADS)

Bagheri, Mohammad Ali; Montazer, Gholam Ali

2011-09-01

In this paper, we test the performance of several ensembles of classifiers and each base learner has been trained on different types of extracted features. Experimental results show the potential benefits introduced by the usage of simple ensemble classification systems for the integration of different types of transient features.

Electrical conductivity of metal powders under pressure

NASA Astrophysics Data System (ADS)

Montes, J. M.; Cuevas, F. G.; Cintas, J.; Urban, P.

2011-12-01

A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called `equivalent simple cubic system', was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

Controlling and prevention of surface wrinkling via size-dependent critical wrinkling strain.

PubMed

Han, Xue; Zhao, Yan; Cao, Yanping; Lu, Conghua

2015-06-14

Surface wrinkling may occur in a film-substrate system when the applied strain exceeds the critical value. However, the practically required strain for the onset of surface wrinkling can be different from the theoretically predicted value. Here we investigate the film size effect-dependent critical strain for the mechanical strain-induced surface wrinkling via a combination of experiments and theoretical analysis. In the poly(dimethylsiloxane)-based system fabricated by the smart combination of mechanical straining and selective O2 plasma (OP) exposure through Cu grids, the film size effect on the critical wrinkling strain is systematically studied by considering OP exposure duration, the mesh number and geometry of Cu grids. Meanwhile, a simple analytical solution revealing the film size effect is well established, which shows good consistency with the experimental results. This study provides an experimental and theoretical basis for finely tuning the critical wrinkling strain in a simple and quantitative manner, which can find a wide range of applications in such fields as microelectronic circuits and optical devices, where controlling and/or prevention of surface wrinkling are of great importance.

Depolarized Rayleigh and Raman Scattering from Simple Fluids.

NASA Astrophysics Data System (ADS)

Varshneya, Deepak

This thesis deals primarily with the investigation of two issues: (1) The collision induced light scattering integrated intensity of argon at the triple point had been measured to be about an order of magnitude smaller than that calculated in a molecular-dynamics (MD) simulation. (2) In studying certain aspects of the structural dynamics reflected in the collision-induced light scattering one is faced with the problem of assigning the various details of the line shape to particular types of motion. In the tetrahedrally symmetric systems, this problem is further complicated due to the orientational motion of particles and has not been carefully examined in the literature. With regard to the first problem, the integrated intensity was carefully measured experimentally and was also calculated in an MD simulation near the triple point by employing a Lennard-Jones (LJ) interaction potential and a simple dipole-induced-dipole (DID) model for the interaction anisotropy. The experimentally measured intensity was found to be 1.7 times smaller than the MD calculated one and is five times bigger than the previous result of Fleury and McTague('1). When the modified model for the interaction anisotropy proposed by Barocchi and Zoppi('2) was used in the MD calculations, the results were found to be in agreement within the experimental error ((TURNEQ) 10%). In the spectra of tetrahedrally symmetric molecules, the experimental collision-induced Rayleigh and Raman spectra at low frequencies ((LESSTHEQ) 20cm('-1)) were decomposed into a Lorentzian function plus a relatively constant background following the theoretical work of Madden.('3) The density behavior of the half-width of the Lorentzian function, (omega)(,L) obtained from the decomposition of the spectra was examined. In the Rayleigh case, it was noted that (omega)(,L) exhibits a maximum at some intermediate liquid density. Using data of various workers('4-6), it was found that (omega)(,L) for all the systems studied exhibited the peaking behaviour. These results are discussed using the free-volume approach of Cohen and Turnbull('7). An attempt has also been made to understand the molecular motions reflected in the spectra of simple molecular systems in light of the atomic systems. It was concluded that the additional degree of freedom (i.e. relative orientations) can be detected in molecular systems by a comparison with the atomic systems of the integrated intensity as a function of density. However, the time scales characteristic of the orientational motion cannot be separated from those of translational motion at liquid densities because the spectra that arise from these motions are superposed.

Laser-Self-Mixing Interferometry for Mechatronics Applications

PubMed Central

Ottonelli, Simona; Dabbicco, Maurizio; De Lucia, Francesco; di Vietro, Michela; Scamarcio, Gaetano

2009-01-01

We report on the development of an all-interferometric optomechatronic sensor for the detection of multi-degrees-of-freedom displacements of a remote target. The prototype system exploits the self-mixing technique and consists only of a laser head, equipped with six laser sources, and a suitably designed reflective target. The feasibility of the system was validated experimentally for both single or multi-degrees-of-freedom measurements, thus demonstrating a simple and inexpensive alternative to costly and bulky existing systems. PMID:22412324

Using heterologous expression systems to characterize potassium and sodium transport activities.

PubMed

Rodríguez, Alonso; Benito, Begoña; Cagnac, Olivier

2012-01-01

The expression of plant transporters in simple well-characterized cell systems is an irreplaceable technique for gaining insights into the kinetic and energetic features of plant transporters. Among all the available expression systems, yeast cells offer the highest simplicity and have the capacity to mimic the in vivo properties of plant transporters. Here, we describe the use of yeast mutants to express K(+) and Na(+) plant transporters and discuss some experimental problems that can produce misleading results.

Mixed-mode oscillations and chaos in a prey-predator system with dormancy of predators.

PubMed

Kuwamura, Masataka; Chiba, Hayato

2009-12-01

It is shown that the dormancy of predators induces mixed-mode oscillations and chaos in the population dynamics of a prey-predator system under certain conditions. The mixed-mode oscillations and chaos are shown to bifurcate from a coexisting equilibrium by means of the theory of fast-slow systems. These results may help to find experimental conditions under which one can demonstrate chaotic population dynamics in a simple phytoplankton-zooplankton (-resting eggs) community in a microcosm with a short duration.

Cooperative action of coherent groups in broadly heterogeneous populations of interacting chemical oscillators

PubMed Central

Mikhailov, A. S.; Zanette, D. H.; Zhai, Y. M.; Kiss, I. Z.; Hudson, J. L.

2004-01-01

We present laboratory experiments on the effects of global coupling in a population of electrochemical oscillators with a multimodal frequency distribution. The experiments show that complex collective signals are generated by this system through spontaneous emergence and joint operation of coherently acting groups representing hierarchically organized resonant clusters. Numerical simulations support these experimental findings. Our results suggest that some forms of internal self-organization, characteristic for complex multiagent systems, are already possible in simple chemical systems. PMID:15263084

Chaotic behaviour of Zeeman machines at introductory course of mechanics

NASA Astrophysics Data System (ADS)

Nagy, Péter; Tasnádi, Péter

2016-05-01

Investigation of chaotic motions and cooperative systems offers a magnificent opportunity to involve modern physics into the basic course of mechanics taught to engineering students. In the present paper it will be demonstrated that Zeeman Machine can be a versatile and motivating tool for students to get introductory knowledge about chaotic motion via interactive simulations. It works in a relatively simple way and its properties can be understood very easily. Since the machine can be built easily and the simulation of its movement is also simple the experimental investigation and the theoretical description can be connected intuitively. Although Zeeman Machine is known mainly for its quasi-static and catastrophic behaviour, its dynamic properties are also of interest with its typical chaotic features. By means of a periodically driven Zeeman Machine a wide range of chaotic properties of the simple systems can be demonstrated such as bifurcation diagrams, chaotic attractors, transient chaos and so on. The main goal of this paper is the presentation of an interactive learning material for teaching the basic features of the chaotic systems through the investigation of the Zeeman Machine.

A simple and sensitive method to measure timing accuracy.

PubMed

De Clercq, Armand; Crombez, Geert; Buysse, Ann; Roeyers, Herbert

2003-02-01

Timing accuracy in presenting experimental stimuli (visual information on a PC or on a TV) and responding (keyboard presses and mouse signals) is of importance in several experimental paradigms. In this article, a simple system for measuring timing accuracy is described. The system uses two PCs (at least Pentium II, 200 MHz), a photocell, and an amplifier. No additional boards and timing hardware are needed. The first PC, a SlavePC, monitors the keyboard presses or mouse signals from the PC under test and uses a photocell that is placed in front of the screen to detect the appearance of visual stimuli on the display. The software consists of a small program running on the SlavePC. The SlavePC is connected through a serial line with a second PC. This MasterPC controls the SlavePC through an ActiveX control, which is used in a Visual Basic program. The accuracy of our system was investigated by using a similar setup of a SlavePC and a MasterPC to generate pulses and by using a pulse generator card. These tests revealed that our system has a 0.01-msec accuracy. As an illustration, the reaction time accuracy of INQUISIT for a few applications was tested using our system. It was found that in those applications that we investigated, INQUISIT measures reaction times from keyboard presses with millisecond accuracy.

Experimental demonstration of record high 19.125 Gb/s real-time end-to-end dual-band optical OFDM transmission over 25 km SMF in a simple EML-based IMDD system.

PubMed

Giddings, R P; Hugues-Salas, E; Tang, J M

2012-08-27

Record high 19.125 Gb/s real-time end-to-end dual-band optical OFDM (OOFDM) transmission is experimentally demonstrated, for the first time, in a simple electro-absorption modulated laser (EML)-based 25 km standard SMF system using intensity modulation and direct detection (IMDD). Adaptively modulated baseband (0-2GHz) and passband (6.125 ± 2GHz) OFDM RF sub-bands, supporting line rates of 10 Gb/s and 9.125 Gb/s respectively, are independently generated and detected with FPGA-based DSP clocked at only 100 MHz and DACs/ADCs operating at sampling speeds as low as 4GS/s. The two OFDM sub-bands are electrically frequency-division-multiplexed (FDM) for intensity modulation of a single optical carrier by an EML. To maximize and balance the signal transmission performance of each sub-band, on-line adaptive features and on-line performance monitoring is fully exploited to optimize key OOFDM transceiver and system parameters, which includes subcarrier characteristics within each individual OFDM sub-band, total and relative sub-band power as well as EML operating conditions. The achieved 19.125 Gb/s over 25 km SMF OOFDM transmission system has an optical power budget of 13.5 dB, and shows almost identical bit error rate (BER) performances for both the baseband and passband signals. In addition, experimental investigations also indicate that the maximum achievable transmission capacity of the present system is mainly determined by the EML frequency chirp-enhanced chromatic dispersion effect, and the passband BER performance is not affected by the two sub-band-induced intermixing effect, which, however, gives a 1.2dB optical power penalty to the baseband signal transmission.

Atomistic simulation of solid-liquid coexistence for molecular systems: application to triazole and benzene.

PubMed

Eike, David M; Maginn, Edward J

2006-04-28

A method recently developed to rigorously determine solid-liquid equilibrium using a free-energy-based analysis has been extended to analyze multiatom molecular systems. This method is based on using a pseudosupercritical transformation path to reversibly transform between solid and liquid phases. Integration along this path yields the free energy difference at a single state point, which can then be used to determine the free energy difference as a function of temperature and therefore locate the coexistence temperature at a fixed pressure. The primary extension reported here is the introduction of an external potential field capable of inducing center of mass order along with secondary orientational order for molecules. The method is used to calculate the melting point of 1-H-1,2,4-triazole and benzene. Despite the fact that the triazole model gives accurate bulk densities for the liquid and crystal phases, it is found to do a poor job of reproducing the experimental crystal structure and heat of fusion. Consequently, it yields a melting point that is 100 K lower than the experimental value. On the other hand, the benzene model has been parametrized extensively to match a wide range of properties and yields a melting point that is only 20 K lower than the experimental value. Previous work in which a simple "direct heating" method was used actually found that the melting point of the benzene model was 50 K higher than the experimental value. This demonstrates the importance of using proper free energy methods to compute phase behavior. It also shows that the melting point is a very sensitive measure of force field quality that should be considered in parametrization efforts. The method described here provides a relatively simple approach for computing melting points of molecular systems.

Biofilm development in fixed bed biofilm reactors: experiments and simple models for engineering design purposes.

PubMed

Szilágyi, N; Kovács, R; Kenyeres, I; Csikor, Zs

2013-01-01

Biofilm development in a fixed bed biofilm reactor system performing municipal wastewater treatment was monitored aiming at accumulating colonization and maximum biofilm mass data usable in engineering practice for process design purposes. Initially a 6 month experimental period was selected for investigations where the biofilm formation and the performance of the reactors were monitored. The results were analyzed by two methods: for simple, steady-state process design purposes the maximum biofilm mass on carriers versus influent load and a time constant of the biofilm growth were determined, whereas for design approaches using dynamic models a simple biofilm mass prediction model including attachment and detachment mechanisms was selected and fitted to the experimental data. According to a detailed statistical analysis, the collected data have not allowed us to determine both the time constant of biofilm growth and the maximum biofilm mass on carriers at the same time. The observed maximum biofilm mass could be determined with a reasonable error and ranged between 438 gTS/m(2) carrier surface and 843 gTS/m(2), depending on influent load, and hydrodynamic conditions. The parallel analysis of the attachment-detachment model showed that the experimental data set allowed us to determine the attachment rate coefficient which was in the range of 0.05-0.4 m d(-1) depending on influent load and hydrodynamic conditions.

Simulations of Flame Acceleration and Deflagration-to-Detonation Transitions in Methane-Air Systems

DTIC Science & Technology

2010-03-17

are neglected. 3. Model parameter calibration The one-step Arrhenius kinetics used in this model cannot ex- actly reproduce all properties of laminar...with obstacles are compared to previ- ously reported experimental data. The results obtained using the simple reaction model qualitatively, and in...have taken in developing a multidimensional numerical model to study explosions in large-scale systems containing mixtures of nat- ural gas and air

General model and control of an n rotor helicopter

NASA Astrophysics Data System (ADS)

Sidea, A. G.; Yding Brogaard, R.; Andersen, N. A.; Ravn, O.

2014-12-01

The purpose of this study was to create a dynamic, nonlinear mathematical model of a multirotor that would be valid for different numbers of rotors. Furthermore, a set of Single Input Single Output (SISO) controllers were implemented for attitude control. Both model and controllers were tested experimentally on a quadcopter. Using the combined model and controllers, simple system simulation and control is possible, by replacing the physical values for the individual systems.

Quasi solution of radiation transport equation

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

Pogosbekyan, L.R.; Lysov, D.A.

There is uncertainty with experimental data as well as with input data of theoretical calculations. The neutron distribution from the variational principle, which takes into account both theoretical and experimental data, is obtained to increase the accuracy and speed of neutronic calculations. The neutron imbalance in mesh cells and the discrepancy between experimentally measured and calculated functional of the neutron distribution are simultaneously minimized. A fast-working and simple-programming iteration method is developed to minimize the objective functional. The method can be used in the core monitoring and control system for (a) power distribution calculations, (b) in- and ex-core detector calibration,more » (c) macro-cross sections or isotope distribution correction by experimental data, and (d) core and detector diagnostics.« less

Simulation and analysis of a model dinoflagellate predator-prey system

NASA Astrophysics Data System (ADS)

Mazzoleni, M. J.; Antonelli, T.; Coyne, K. J.; Rossi, L. F.

2015-12-01

This paper analyzes the dynamics of a model dinoflagellate predator-prey system and uses simulations to validate theoretical and experimental studies. A simple model for predator-prey interactions is derived by drawing upon analogies from chemical kinetics. This model is then modified to account for inefficiencies in predation. Simulation results are shown to closely match the model predictions. Additional simulations are then run which are based on experimental observations of predatory dinoflagellate behavior, and this study specifically investigates how the predatory dinoflagellate Karlodinium veneficum uses toxins to immobilize its prey and increase its feeding rate. These simulations account for complex dynamics that were not included in the basic models, and the results from these computational simulations closely match the experimentally observed predatory behavior of K. veneficum and reinforce the notion that predatory dinoflagellates utilize toxins to increase their feeding rate.

Experimental quantum information processing with the Talbot effect

NASA Astrophysics Data System (ADS)

Sawada, K.; Walborn, S. P.

2018-07-01

We report a proof of concept experiment illustrating the implementation of several simple quantum logic gates on D-level quantum systems (quDits) using the Talbot effect. A number of QuDit states are encoded into the transverse profile of a paraxial laser beam using a spatial light modulator. These states are transformed through a diagonal phase element and then free-propagation via the fractional Talbot effect, demonstrating the realization of some well-known single quDit gates in quantum computation. Our classical optics experiment allows us to identify several important technical details, and serves as a first experimental step in performing D-dimensional quantum operations with single photons or other quantum systems using this scheme.

Practical Entanglement Estimation for Spin-System Quantum Simulators.

PubMed

Marty, O; Cramer, M; Plenio, M B

2016-03-11

We present practical methods to measure entanglement for quantum simulators that can be realized with trapped ions, cold atoms, and superconducting qubits. Focusing on long- and short-range Ising-type Hamiltonians, we introduce schemes that are applicable under realistic experimental conditions including mixedness due to, e.g., noise or temperature. In particular, we identify a single observable whose expectation value serves as a lower bound to entanglement and that may be obtained by a simple quantum circuit. As such circuits are not (yet) available for every platform, we investigate the performance of routinely measured observables as quantitative entanglement witnesses. Possible applications include experimental studies of entanglement scaling in critical systems and the reliable benchmarking of quantum simulators.

Effect of formal specifications on program complexity and reliability: An experimental study

NASA Technical Reports Server (NTRS)

Goel, Amrit L.; Sahoo, Swarupa N.

1990-01-01

The results are presented of an experimental study undertaken to assess the improvement in program quality by using formal specifications. Specifications in the Z notation were developed for a simple but realistic antimissile system. These specifications were then used to develop 2 versions in C by 2 programmers. Another set of 3 versions in Ada were independently developed from informal specifications in English. A comparison of the reliability and complexity of the resulting programs suggests the advantages of using formal specifications in terms of number of errors detected and fault avoidance.

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

Li, Sucheng; Duan, Qian; Li, Shuo

We experimentally demonstrate that perfect electromagnetic absorption can be realized in the one-atom thick graphene. Employing coherent illumination in the waveguide system, the absorbance of the unpatterned graphene monolayer is observed to be greater than 94% over the microwave X-band, 7–13 GHz, and to achieve a full absorption, >99% in experiment, at ∼8.3 GHz. In addition, the absorption characteristic manifests equivalently a wide range of incident angle. The experimental results agree very well with the theoretical calculations. Our work accomplishes the broadband, wide-angle, high-performance absorption in the thinnest material with simple configuration.

The role of compressional viscoelasticity in the lubrication of rolling contacts.

NASA Technical Reports Server (NTRS)

Harrison, G.; Trachman, E. G.

1972-01-01

A simple model for the time-dependent volume response of a liquid to an applied pressure step is used to calculate the variation with rolling speed of the traction coefficient in a rolling contact system. Good agreement with experimental results is obtained at rolling speeds above 50 in/sec. At lower rolling speeds a very rapid change in the effective viscosity of the lubricant is predicted. This behavior, in conjunction with shear rate effects, is shown to lead to large errors when experimental data are extrapolated to zero rolling speed.

Experimental and analytical investigation of inertial propulsion mechanisms and motion simulation of rigid multi-body mechanical systems

NASA Astrophysics Data System (ADS)

Almesallmy, Mohammed

Methodologies are developed for dynamic analysis of mechanical systems with emphasis on inertial propulsion systems. This work adopted the Lagrangian methodology. Lagrangian methodology is the most efficient classical computational technique, which we call Equations of Motion Code (EOMC). The EOMC is applied to several simple dynamic mechanical systems for easier understanding of the method and to aid other investigators in developing equations of motion of any dynamic system. In addition, it is applied to a rigid multibody system, such as Thomson IPS [Thomson 1986]. Furthermore, a simple symbolic algorithm is developed using Maple software, which can be used to convert any nonlinear n-order ordinary differential equation (ODE) systems into 1st-order ODE system in ready format to be used in Matlab software. A side issue, but equally important, we have started corresponding with the U.S. Patent office to persuade them that patent applications, claiming gross linear motion based on inertial propulsion systems should be automatically rejected. The precedent is rejection of patent applications involving perpetual motion machines.

Energy balance model applied to pasture experimental areas in São Paulo State, Brazil

NASA Astrophysics Data System (ADS)

Bayma-Silva, Gustavo; de Castro Teixeira, Antonio Heriberto; de Castro Victoria, Daniel; Furlan Nogueira, Sandra; Freitas Leivas, Janice; Coaguila, Daniel N.; Rodrigues Herling, Valdo

2016-10-01

The Simple Algorithm for Evapotranspiration Retrieving (SAFER) was used to estimate biophysical parameters and the energy balance components in two different pasture experimental areas, in the São Paulo state, Brazil. The experimental pastures consist in six rotational (RGS) and three continuous grazing systems (CGS) paddocks. Landsat-8 images from 2013 and 2015 dry and rainy seasons were used, as these presented similar hydrological cycle, with 1,600 mm and 1,613 mm of annual precipitation, resulting in 19 cloud-free images. Bands 1 to 7 and thermal bands 10 and 11 were used with weather data from a station located near the experimental area. NDVI, biomass, evapotranspiration and latent heat flux (λE) temporal values statistically differ CGS from RGS areas. Grazing systems influences the energy partition and these results indicate that RGS benefits biomass production, evapotranspiration and the microclimate, due higher LE values. SAFER is a feasible tool to estimate biophysical parameters and energy balance components in pasture and has potential to discriminate continuous and rotation grazing systems in a temporal analysis.

Experimental Investigation of a Direct-drive Hall Thruster and Solar Array System at Power Levels up to 10 kW

NASA Technical Reports Server (NTRS)

Snyder, John S.; Brophy, John R.; Hofer, Richard R.; Goebel, Dan M.; Katz, Ira

2012-01-01

As NASA considers future exploration missions, high-power solar-electric propulsion (SEP) plays a prominent role in achieving many mission goals. Studies of high-power SEP systems (i.e. tens to hundreds of kilowatts) suggest that significant mass savings may be realized by implementing a direct-drive power system, so NASA recently established the National Direct-Drive Testbed to examine technical issues identified by previous investigations. The testbed includes a 12-kW solar array and power control station designed to power single and multiple Hall thrusters over a wide range of voltages and currents. In this paper, single Hall thruster operation directly from solar array output at discharge voltages of 200 to 450 V and discharge powers of 1 to 10 kW is reported. Hall thruster control and operation is shown to be simple and no different than for operation on conventional power supplies. Thruster and power system electrical oscillations were investigated over a large range of operating conditions and with different filter capacitances. Thruster oscillations were the same as for conventional power supplies, did not adversely affect solar array operation, and were independent of filter capacitance from 8 to 80 ?F. Solar array current and voltage oscillations were very small compared to their mean values and showed a modest dependence on capacitor size. No instabilities or anomalous behavior were observed in the thruster or power system at any operating condition investigated, including near and at the array peak power point. Thruster startup using the anode propellant flow as the power 'switch' was shown to be simple and reliable with system transients mitigated by the proper selection of filter capacitance size. Shutdown via cutoff of propellant flow was also demonstrated. A simple electrical circuit model was developed and is shown to have good agreement with the experimental data.

Droplet formation at the non-equilibrium water/water (w/w) interface

NASA Astrophysics Data System (ADS)

Chao, Youchuang; Mak, Sze Yi; Kong, Tiantian; Ding, Zijing; Shum, Ho Cheung

2017-11-01

The interfacial instability at liquid-liquid interfaces has been intensively studied in recent years due to their important role in nature and technology. Among them, two classic instabilities are Rayleigh-Taylor (RT) and double diffusive (DD) instabilities, which are practically relevant to many industrial processes, such as geologic CO2 sequestration. Most experimental and theoretical works have focused on RT or DD instability in binary systems. However, the study of such instability in complex systems, such as non-equilibrium ternary systems that involves mass-transfer-induced phase separation, has received less attention. Here, by using a ternary system known as the aqueous two-phase system (ATPS), we investigate experimentally the behavior of non-equilibrium water/water (w/w) interfaces in a vertically orientated Hele-Shaw cell. We observe that an array of fingers emerge at the w/w interface, and then break into droplets. We explore the instability using different concentrations of two aqueous phases. Our experimental findings are expected to inspire the mass production of all-aqueous emulsions in a simple setup.

Preparation and Analysis of Positioned Mononucleosomes

PubMed Central

Kulaeva, Olga; Studitsky, Vasily M.

2016-01-01

Short DNA fragments containing single nucleosomes have been extensively employed as simple model experimental systems for analysis of many intranuclear processes, including binding of proteins to nucleosomes, covalent histone modifications, transcription, DNA repair and ATP-dependent chromatin remodeling. Here we describe several recently developed procedures for obtaining and analysis of mononucleosomes assembled on 200–350-bp DNA fragments. PMID:25827872

Application of Influence Diagrams in Identifying Soviet Satellite Missions

DTIC Science & Technology

1990-12-01

Probabilities Comparison ......................... 58 35. Continuous Model Variables ............................ 59 36. Sample Inclination Data...diagramming is a method which allows the simple construction of a model to illustrate the interrelationships which exist among variables by capturing an...environmental monitoring systems. The module also contained an array of instruments for geophysical and astrophysical experimentation . 4.3.14.3 Soyuz. The Soyuz

Organizing principles as tools for bridging the gap between system theory and biological experimentation.

PubMed

Mekios, Constantinos

2016-04-01

Twentieth-century theoretical efforts towards the articulation of general system properties came short of having the significant impact on biological practice that their proponents envisioned. Although the latter did arrive at preliminary mathematical formulations of such properties, they had little success in showing how these could be productively incorporated into the research agenda of biologists. Consequently, the gap that kept system-theoretic principles cut-off from biological experimentation persisted. More recently, however, simple theoretical tools have proved readily applicable within the context of systems biology. In particular, examples reviewed in this paper suggest that rigorous mathematical expressions of design principles, imported primarily from engineering, could produce experimentally confirmable predictions of the regulatory properties of small biological networks. But this is not enough for contemporary systems biologists who adopt the holistic aspirations of early systemologists, seeking high-level organizing principles that could provide insights into problems of biological complexity at the whole-system level. While the presented evidence is not conclusive about whether this strategy could lead to the realization of the lofty goal of a comprehensive explanatory integration, it suggests that the ongoing quest for organizing principles is pragmatically advantageous for systems biologists. The formalisms postulated in the course of this process can serve as bridges between system-theoretic concepts and the results of molecular experimentation: they constitute theoretical tools for generalizing molecular data, thus producing increasingly accurate explanations of system-wide phenomena.

Determination of high temperature strains using a PC based vision system

NASA Astrophysics Data System (ADS)

McNeill, Stephen R.; Sutton, Michael A.; Russell, Samuel S.

1992-09-01

With the widespread availability of video digitizers and cheap personal computers, the use of computer vision as an experimental tool is becoming common place. These systems are being used to make a wide variety of measurements that range from simple surface characterization to velocity profiles. The Sub-Pixel Digital Image Correlation technique has been developed to measure full field displacement and gradients of the surface of an object subjected to a driving force. The technique has shown its utility by measuring the deformation and movement of objects that range from simple translation to fluid velocity profiles to crack tip deformation of solid rocket fuel. This technique has recently been improved and used to measure the surface displacement field of an object at high temperature. The development of a PC based Sub-Pixel Digital Image Correlation system has yielded an accurate and easy to use system for measuring surface displacements and gradients. Experiments have been performed to show the system is viable for measuring thermal strain.

Structure and atomic correlations in molecular systems probed by XAS reverse Monte Carlo refinement

NASA Astrophysics Data System (ADS)

Di Cicco, Andrea; Iesari, Fabio; Trapananti, Angela; D'Angelo, Paola; Filipponi, Adriano

2018-03-01

The Reverse Monte Carlo (RMC) algorithm for structure refinement has been applied to x-ray absorption spectroscopy (XAS) multiple-edge data sets for six gas phase molecular systems (SnI2, CdI2, BBr3, GaI3, GeBr4, GeI4). Sets of thousands of molecular replicas were involved in the refinement process, driven by the XAS data and constrained by available electron diffraction results. The equilibrated configurations were analysed to determine the average tridimensional structure and obtain reliable bond and bond-angle distributions. Detectable deviations from Gaussian models were found in some cases. This work shows that a RMC refinement of XAS data is able to provide geometrical models for molecular structures compatible with present experimental evidence. The validation of this approach on simple molecular systems is particularly important in view of its possible simple extension to more complex and extended systems including metal-organic complexes, biomolecules, or nanocrystalline systems.

A Simple and Low-Cost Monitoring System to Investigate Environmental Conditions in a Biological Research Laboratory.

PubMed

Gurdita, Akshay; Vovko, Heather; Ungrin, Mark

2016-01-01

Basic equipment such as incubation and refrigeration systems plays a critical role in nearly all aspects of the traditional biological research laboratory. Their proper functioning is therefore essential to ensure reliable and repeatable experimental results. Despite this fact, in many academic laboratories little attention is paid to validating and monitoring their function, primarily due to the cost and/or technical complexity of available commercial solutions. We have therefore developed a simple and low-cost monitoring system that combines a "Raspberry Pi" single-board computer with USB-connected sensor interfaces to track and log parameters such as temperature and pressure, and send email alert messages as appropriate. The system is controlled by open-source software, and we have also generated scripts to automate software setup so that no background in programming is required to install and use it. We have applied it to investigate the behaviour of our own equipment, and present here the results along with the details of the monitoring system used to obtain them.

Pulsed Rabi oscillations in quantum two-level systems: beyond the area theorem

NASA Astrophysics Data System (ADS)

Fischer, Kevin A.; Hanschke, Lukas; Kremser, Malte; Finley, Jonathan J.; Müller, Kai; Vučković, Jelena

2018-01-01

The area theorem states that when a short optical pulse drives a quantum two-level system, it undergoes Rabi oscillations in the probability of scattering a single photon. In this work, we investigate the breakdown of the area theorem as both the pulse length becomes non-negligible and for certain pulse areas. Using simple quantum trajectories, we provide an analytic approximation to the photon emission dynamics of a two-level system. Our model provides an intuitive way to understand re-excitation, which elucidates the mechanism behind the two-photon emission events that can spoil single-photon emission. We experimentally measure the emission statistics from a semiconductor quantum dot, acting as a two-level system, and show good agreement with our simple model for short pulses. Additionally, the model clearly explains our recent results (Fischer and Hanschke 2017 et al Nat. Phys.) showing dominant two-photon emission from a two-level system for pulses with interaction areas equal to an even multiple of π.

Experimental Verification of Entanglement Generated in a Plasmonic System.

PubMed

Dieleman, F; Tame, M S; Sonnefraud, Y; Kim, M S; Maier, S A

2017-12-13

A core process in many quantum tasks is the generation of entanglement. It is being actively studied in a variety of physical settings-from simple bipartite systems to complex multipartite systems. In this work we experimentally study the generation of bipartite entanglement in a nanophotonic system. Entanglement is generated via the quantum interference of two surface plasmon polaritons in a beamsplitter structure, i.e., utilizing the Hong-Ou-Mandel (HOM) effect, and its presence is verified using quantum state tomography. The amount of entanglement is quantified by the concurrence and we find values of up to 0.77 ± 0.04. Verifying entanglement in the output state from HOM interference is a nontrivial task and cannot be inferred from the visibility alone. The techniques we use to verify entanglement could be applied to other types of photonic system and therefore may be useful for the characterization of a range of different nanophotonic quantum devices.

Experimental framework to study tip vortex interactions in multirotor wakes

NASA Astrophysics Data System (ADS)

Yao, Rongnan; Araya, Daniel

2017-11-01

We present an experimental study to compare the dynamic characteristics of tip vortices shed from a propeller in a crossflow to similar characteristics of an isolated vortex column generated in a closed system. Our aim is to evaluate the feasibility of using this simple isolated system to study the more complicated three-dimensional vortex interactions inherent to multirotor wakes, where the local unsteadiness generated by one rotor can strongly impact the performance of nearby rotors. Time-resolved particle image velocimetry is used to measure the velocity field of the propeller wake flow in a wind tunnel and the vortex column in a water tank. Specific attention is placed on analyzing the observed vortex core precession in the isolated system and comparing this to characteristic tip-vortex wandering phenomenon.

Analysis and Experimental Investigation of Optimum Design of Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

NASA Astrophysics Data System (ADS)

Elarusi, Abdulmunaem; Attar, Alaa; Lee, HoSung

2018-02-01

The optimum design of a thermoelectric system for application in car seat climate control has been modeled and its performance evaluated experimentally. The optimum design of the thermoelectric device combining two heat exchangers was obtained by using a newly developed optimization method based on the dimensional technique. Based on the analytical optimum design results, commercial thermoelectric cooler and heat sinks were selected to design and construct the climate control heat pump. This work focuses on testing the system performance in both cooling and heating modes to ensure accurate analytical modeling. Although the analytical performance was calculated using the simple ideal thermoelectric equations with effective thermoelectric material properties, it showed very good agreement with experiment for most operating conditions.

The experimental results of a self tuning adaptive controller using online frequency identification. [for Galileo spacecraft

NASA Technical Reports Server (NTRS)

Chiang, W.-W.; Cannon, R. H., Jr.

1985-01-01

A fourth-order laboratory dynamic system featuring very low structural damping and a noncolocated actuator-sensor pair has been used to test a novel real-time adaptive controller, implemented in a minicomputer, which consists of a state estimator, a set of state feedback gains, and a frequency-locked loop for real-time parameter identification. The adaptation algorithm employed can correct controller error and stabilize the system for more than 50 percent variation in the plant's natural frequency, compared with a 10 percent stability margin in frequency variation for a fixed gain controller having the same performance as the nominal plant condition. The very rapid convergence achievable by this adaptive system is demonstrated experimentally, and proven with simple, root-locus methods.

Experimental Measurements of Spreading of Volatile Liquid Droplets

NASA Technical Reports Server (NTRS)

Zhang, Neng-Li; Chao, David F.

2001-01-01

Based on the laser shadowgraphic system used by the first author of the present paper, a simple optical system, which combined the laser shadowgraphy and the direct magnified-photography, has been developed to measure the contact angle, the spreading speed, and the evaporation rate. Additionally, the system can also visualize thermocapillary convection inside of a sessile drop simultaneously. The experimental results show that evaporation/condensation and thermocapillary convection in the sessile drop induced by the evaporation strongly affects the wetting and spreading of the drop. Condensation always promotes the wetting and spreading of the drop. Evaporation may increase or decrease the contact angle of the evaporating sessile drops, depending on the evaporation rate. The thermocapillary convection in the drop induced by the evaporation enhances the effects of evaporation to suppress the spreading.

Versatile microrobotics using simple modular subunits

NASA Astrophysics Data System (ADS)

Cheang, U. Kei; Meshkati, Farshad; Kim, Hoyeon; Lee, Kyoungwoo; Fu, Henry Chien; Kim, Min Jun

2016-07-01

The realization of reconfigurable modular microrobots could aid drug delivery and microsurgery by allowing a single system to navigate diverse environments and perform multiple tasks. So far, microrobotic systems are limited by insufficient versatility; for instance, helical shapes commonly used for magnetic swimmers cannot effectively assemble and disassemble into different size and shapes. Here by using microswimmers with simple geometries constructed of spherical particles, we show how magnetohydrodynamics can be used to assemble and disassemble modular microrobots with different physical characteristics. We develop a mechanistic physical model that we use to improve assembly strategies. Furthermore, we experimentally demonstrate the feasibility of dynamically changing the physical properties of microswimmers through assembly and disassembly in a controlled fluidic environment. Finally, we show that different configurations have different swimming properties by examining swimming speed dependence on configuration size.

Versatile microrobotics using simple modular subunits

PubMed Central

Cheang, U Kei; Meshkati, Farshad; Kim, Hoyeon; Lee, Kyoungwoo; Fu, Henry Chien; Kim, Min Jun

2016-01-01

The realization of reconfigurable modular microrobots could aid drug delivery and microsurgery by allowing a single system to navigate diverse environments and perform multiple tasks. So far, microrobotic systems are limited by insufficient versatility; for instance, helical shapes commonly used for magnetic swimmers cannot effectively assemble and disassemble into different size and shapes. Here by using microswimmers with simple geometries constructed of spherical particles, we show how magnetohydrodynamics can be used to assemble and disassemble modular microrobots with different physical characteristics. We develop a mechanistic physical model that we use to improve assembly strategies. Furthermore, we experimentally demonstrate the feasibility of dynamically changing the physical properties of microswimmers through assembly and disassembly in a controlled fluidic environment. Finally, we show that different configurations have different swimming properties by examining swimming speed dependence on configuration size. PMID:27464852

Mobile robot self-localization system using single webcam distance measurement technology in indoor environments.

PubMed

Li, I-Hsum; Chen, Ming-Chang; Wang, Wei-Yen; Su, Shun-Feng; Lai, To-Wen

2014-01-27

A single-webcam distance measurement technique for indoor robot localization is proposed in this paper. The proposed localization technique uses webcams that are available in an existing surveillance environment. The developed image-based distance measurement system (IBDMS) and parallel lines distance measurement system (PLDMS) have two merits. Firstly, only one webcam is required for estimating the distance. Secondly, the set-up of IBDMS and PLDMS is easy, which only one known-dimension rectangle pattern is needed, i.e., a ground tile. Some common and simple image processing techniques, i.e., background subtraction are used to capture the robot in real time. Thus, for the purposes of indoor robot localization, the proposed method does not need to use expensive high-resolution webcams and complicated pattern recognition methods but just few simple estimating formulas. From the experimental results, the proposed robot localization method is reliable and effective in an indoor environment.

Various Attractors, Coexisting Attractors and Antimonotonicity in a Simple Fourth-Order Memristive Twin-T Oscillator

NASA Astrophysics Data System (ADS)

Zhou, Ling; Wang, Chunhua; Zhang, Xin; Yao, Wei

By replacing the resistor in a Twin-T network with a generalized flux-controlled memristor, this paper proposes a simple fourth-order memristive Twin-T oscillator. Rich dynamical behaviors can be observed in the dynamical system. The most striking feature is that this system has various periodic orbits and various chaotic attractors generated by adjusting parameter b. At the same time, coexisting attractors and antimonotonicity are also detected (especially, two full Feigenbaum remerging trees in series are observed in such autonomous chaotic systems). Their dynamical features are analyzed by phase portraits, Lyapunov exponents, bifurcation diagrams and basin of attraction. Moreover, hardware experiments on a breadboard are carried out. Experimental measurements are in accordance with the simulation results. Finally, a multi-channel random bit generator is designed for encryption applications. Numerical results illustrate the usefulness of the random bit generator.

A Simple fMRI Compatible Robotic Stimulator to Study the Neural Mechanisms of Touch and Pain.

PubMed

Riillo, F; Bagnato, C; Allievi, A G; Takagi, A; Fabrizi, L; Saggio, G; Arichi, T; Burdet, E

2016-08-01

This paper presents a simple device for the investigation of the human somatosensory system with functional magnetic imaging (fMRI). PC-controlled pneumatic actuation is employed to produce innocuous or noxious mechanical stimulation of the skin. Stimulation patterns are synchronized with fMRI and other relevant physiological measurements like electroencephalographic activity and vital physiological parameters. The system allows adjustable regulation of stimulation parameters and provides consistent patterns of stimulation. A validation experiment demonstrates that the system safely and reliably identifies clusters of functional activity in brain regions involved in the processing of pain. This new device is inexpensive, portable, easy-to-assemble and customizable to suit different experimental requirements. It provides robust and consistent somatosensory stimulation, which is of crucial importance to investigating the mechanisms of pain and its strong connection with the sense of touch.

Mobile Robot Self-Localization System Using Single Webcam Distance Measurement Technology in Indoor Environments

PubMed Central

Li, I-Hsum; Chen, Ming-Chang; Wang, Wei-Yen; Su, Shun-Feng; Lai, To-Wen

2014-01-01

A single-webcam distance measurement technique for indoor robot localization is proposed in this paper. The proposed localization technique uses webcams that are available in an existing surveillance environment. The developed image-based distance measurement system (IBDMS) and parallel lines distance measurement system (PLDMS) have two merits. Firstly, only one webcam is required for estimating the distance. Secondly, the set-up of IBDMS and PLDMS is easy, which only one known-dimension rectangle pattern is needed, i.e., a ground tile. Some common and simple image processing techniques, i.e., background subtraction are used to capture the robot in real time. Thus, for the purposes of indoor robot localization, the proposed method does not need to use expensive high-resolution webcams and complicated pattern recognition methods but just few simple estimating formulas. From the experimental results, the proposed robot localization method is reliable and effective in an indoor environment. PMID:24473282

Exploitation of Ubiquitous Wi-Fi Devices as Building Blocks for Improvised Motion Detection Systems.

PubMed

Soldovieri, Francesco; Gennarelli, Gianluca

2016-02-27

This article deals with a feasibility study on the detection of human movements in indoor scenarios based on radio signal strength variations. The sensing principle exploits the fact that the human body interacts with wireless signals, introducing variations of the radiowave fields due to shadowing and multipath phenomena. As a result, human motion can be inferred from fluctuations of radiowave power collected by a receiving terminal. In this paper, we investigate the potentialities of widely available wireless communication devices in order to develop an improvised motion detection system (IMDS). Experimental tests are performed in an indoor environment by using a smartphone as a Wi-Fi access point and a laptop with dedicated software as a receiver. Simple detection strategies tailored for real-time operation are implemented to process the received signal strength measurements. The achieved results confirm the potentialities of the simple system here proposed to reliably detect human motion in operational conditions.

Application of simple adaptive control to water hydraulic servo cylinder system

NASA Astrophysics Data System (ADS)

Ito, Kazuhisa; Yamada, Tsuyoshi; Ikeo, Shigeru; Takahashi, Koji

2012-09-01

Although conventional model reference adaptive control (MRAC) achieves good tracking performance for cylinder control, the controller structure is much more complicated and has less robustness to disturbance in real applications. This paper discusses the use of simple adaptive control (SAC) for positioning a water hydraulic servo cylinder system. Compared with MRAC, SAC has a simpler and lower order structure, i.e., higher feasibility. The control performance of SAC is examined and evaluated on a water hydraulic servo cylinder system. With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic, and pneumatic drive systems. This technique is also preferred because of its high power density, high safety against fire hazards in production plants, and easy availability. However, the main problems for precise control in a water hydraulic system are steady state errors and overshoot due to its large friction torque and considerable leakage flow. MRAC has been already applied to compensate for these effects, and better control performances have been obtained. However, there have been no reports on the application of SAC for water hydraulics. To make clear the merits of SAC, the tracking control performance and robustness are discussed based on experimental results. SAC is confirmed to give better tracking performance compared with PI control, and a control precision comparable to MRAC (within 10 μm of the reference position) and higher robustness to parameter change, despite the simple controller. The research results ensure a wider application of simple adaptive control in real mechanical systems.

Solar photovoltaic power system for a radio station

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

Nichols, B. E.

1980-12-01

Under sponsorship of the US Department of Energy, Massachusetts Institute of Technology Lincoln Laboratory has developed a concept for a small photovoltaic power system. Of simple construction, the system uses low-cost, prefabricated, transportable units for easy, fast installation and requires minimal site preparation. The first application of this experimental system began operation in August 1979 at daytime AM radio station WNBO in Bryan, Ohio. The project was jointly undertaken by the Laboratory and the radio station. The photovoltaic system described holds promise for a wide range of applications and economic feasibility by the mid- to late-1980s.

Dynamic stability of maglev systems

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

Cai, Y.; Chen, S.S.; Mulcahy, T.M.

1992-09-01

Since the occurrence of dynamic instabilities is not acceptable for any commercial maglev systems, it is important to consider the dynamic instability in the development of all maglev systems. This study is to consider the stability of maglev systems based on experimental data, scoping calculations and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on the guideway which consists of double L-shaped aluminum segments attached to a rotating wheel. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev system.

Development of Skylab experiment T020 employing a foot controlled maneuvering unit

NASA Technical Reports Server (NTRS)

Hewes, D. E.; Glover, K. E.

1972-01-01

A review of the plans and preparations is presented for Skylab experiment T020, entitled Foot-Controlled Maneuvering Unit (FCMU). The FCMU is an experimental system intended to explore the use of simple astronaut maneuvering devices in the zero-gravity environment of space. This review also includes discussions of the FCMU concept and experiment hardware systems, as well as supporting experiment definition and development research studies conducted with the aid of zero-gravity simulators.

Extending the frequency of response of lightly damped second order systems: Application to the drag force anemometer

NASA Technical Reports Server (NTRS)

Fralick, G. C.

1982-01-01

It is shown that a conventional electronic frequency compensator does not provide adequate compensation near the resonant frequency of a lightly damped second order system, such as the drag force anemometer. The reason for this is discussed, and a simple circuit modification is presented which overcomes the difficulty. The improvement is shown in theoretical frequency response curves as well as in the experimental results from some typical drag force anemometers.

Demonstration of 20Gb/s polarization-insensitive wavelength switching system for high-speed free-space optical network

NASA Astrophysics Data System (ADS)

Qian, Feng-chen; Ye, Ya-lin; Wen, Yu; Duan, Tao; Feng, Huan

2015-10-01

A 20Gb/s polarization-insensitive all-optical wavelength switching system for high-speed free-space optical communication (FSO) network is experimentally demonstrated All-optical wavelength conversion (AOWC) is implemented using four-wave mixing (FWM) by highly-nonlinear fiber (HNLF). In the experimental setup, a simple actively mode-locked fiber ring laser (AML-FRL) with repetition frequency from 1 to 15 GHz is used to generate eight 2.5Gb/s tributary signals, which are multiplexed into one 20Gb/s optical data stream. At the receiver, the 20 Gb/s OTDM data stream is demultiplexed down to 2.5 Gb/s via a polarization-insensitive FWM scheme. The whole space communication distance is over 10 meters in building hallway. The experimental results show that this system can stably run over 24 hours at 10-9 BER level, thus the proposed architecture can work at higher rate with wavelength-division multiplexing (WDM) and high order modulation schemes.

The CaO orange system in meteor spectra

NASA Astrophysics Data System (ADS)

Berezhnoy, A. A.; Borovička, J.; Santos, J.; Rivas-Silva, J. F.; Sandoval, L.; Stolyarov, A. V.; Palma, A.

2018-02-01

The CaO orange band system was simulated in the region 5900-6300 Å and compared with the experimentally observed spectra of Benešov bolide wake. The required vibronic Einstein emission coefficients were estimated by means of the experimental radiative lifetimes under the simplest Franck-Condon approximation. A moderate agreement was achieved, and the largest uncertainties come from modeling shape of FeO orange bands. Using a simple model the CaO column density in the wake of the Benešov bolide at the height of 29 km was estimated as (5 ± 2) × 1014 cm-2 by a comparison of the present CaO spectra with the AlO bands nicely observed at 4600-5200 Å in the same spectrum. The obtained CaO content is in a good agreement with the quenching model developed for the impact-produced cloud, although future theoretical and experimental studies of both CaO and FeO orange systems contribution would be needed to confirm these results.

Development and experimental validation of downlink multiuser MIMO-OFDM in gigabit wireless LAN systems

NASA Astrophysics Data System (ADS)

Ishihara, Koichi; Asai, Yusuke; Kudo, Riichi; Ichikawa, Takeo; Takatori, Yasushi; Mizoguchi, Masato

2013-12-01

Multiuser multiple-input multiple-output (MU-MIMO) has been proposed as a means to improve spectrum efficiency for various future wireless communication systems. This paper reports indoor experimental results obtained for a newly developed and implemented downlink (DL) MU-MIMO orthogonal frequency division multiplexing (OFDM) transceiver for gigabit wireless local area network systems in the microwave band. In the transceiver, the channel state information (CSI) is estimated at each user and fed back to an access point (AP) on a real-time basis. At the AP, the estimated CSI is used to calculate the transmit beamforming weight for DL MU-MIMO transmission. This paper also proposes a recursive inverse matrix computation scheme for computing the transmit weight in real time. Experiments with the developed transceiver demonstrate its feasibility in a number of indoor scenarios. The experimental results clarify that DL MU-MIMO-OFDM transmission can achieve a 972-Mbit/s transmission data rate with simple digital signal processing of single-antenna users in an indoor environment.

Rendering the "Not-So-Simple" Pendulum Experimentally Accessible.

ERIC Educational Resources Information Center

Jackson, David P.

1996-01-01

Presents three methods for obtaining experimental data related to acceleration of a simple pendulum. Two of the methods involve angular position measurements and the subsequent calculation of the acceleration while the third method involves a direct measurement of the acceleration. Compares these results with theoretical calculations and…

A theoretical and experimental investigation of impact control for manipulators

NASA Technical Reports Server (NTRS)

Volpe, Richard; Khosla, Pradeep

1993-01-01

This article describes a simple control strategy for stable hardon-hard contact of a manipulator with the environment. The strategy is motivated by recognition of the equivalence of proportional gain explicit force control and impedance control. It is shown that negative proportional force gains, or impedance mass ratios less than unity, can equivalently provide excellent impact response without bouncing. This result is indicated by an analysis performed with an experimentally determined arm/sensor/environment model. The results are corroborated by experimental data from implementation of the control algorithms on the CMU DD Arm II system. The results confirm that manipulator impact against a stiff environment without bouncing can be readily handled by this novel control strategy.

Stereoisomeric effects on dynamic viscosity versus pressure and temperature for the system cis- + trans-decalin

NASA Astrophysics Data System (ADS)

Miyake, Yasufumi; Boned, Christian; Baylaucq, Antoine; Bessières, David; Zéberg-Mikkelsen, Claus K.; Galliéro, Guillaume; Ushiki, Hideharu

2007-07-01

In order to study the influence of stereoisomeric effects on the dynamic viscosity, an extensive experimental study of the viscosity of the binary system composed of the two stereoisomeric molecular forms of decalin - cis and trans - has been carried out for five different mixtures at three temperatures (303.15, 323.15 and 343.15) K and six isobars up to 100 MPa with a falling-body viscometer (a total of 90 points). The experimental relative uncertainty is estimated to be 2%. The variations of dynamic viscosity versus composition are discussed with respect to their behavior due to stereoisomerism. Four different models with a physical and theoretical background are studied in order to investigate how they take the stereoisomeric effect into account through their required model parameters. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. Overall, a satisfactory representation of the viscosity of this binary system is found for the different models within the considered ( T, p) range taken into account their simplicity. All the models are able to distinguish between the two stereoisomeric decalin compounds. Further, based on the analysis of the model parameters performed on the pure compounds, it has been found that the use of simple mixing rules without introducing any binary interaction parameters are sufficient in order to predict the viscosity of cis + trans-decalin mixtures with the same accuracy in comparison with the experimental values as obtained for the pure compounds. In addition to these models, a semi-empirical self-referencing model and the simple mixing laws of Grunberg-Nissan and Katti-Chaudhri are also applied in the representation of the viscosity behavior of these systems.

Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System.

PubMed

Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

2017-03-31

The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian S_{z}I_{z} on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System

NASA Astrophysics Data System (ADS)

Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

2017-03-01

The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian SzIz on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

PubMed

Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

2016-04-18

The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

Consequences of viscous anisotropy for melt localization in a deforming, two-phase aggregate

NASA Astrophysics Data System (ADS)

Takei, Y.; Katz, R. F.

2012-12-01

Melt localization in the deforming, partially molten mantle has been of interest because it affects the melt extraction rate, mantle deformability, and chemical interaction between the melt and host rock. Experimental studies have reported the spontaneous segregation of melt into melt-rich bands in samples deformed under simple shear and torsion (Holtzman et al, 2003, King et al, 2010). Efforts to clarify the instability mechanism have so far revealed that rheological properties of partially molten rocks control the occurrence of instability. Porosity-weakening viscosity, empirically written as exp(- λ × f) with porosity f and constant λ(= 25-45), plays an essential role in the destabilization of porosity perturbation in the shear flow of a two-phase aggregate (eg., pure shear flow, simple shear flow): the perturbation growth rate is proportional to the product of shear strain rate and the factor λ (Stevenson, 1989). The stress exponent n of the viscosity affects the angle of the perturbation plane with maximum growthrate, where n=3-6 (power-law creep) explains the experimentally observed low angle to the shear plane (Katz et al, 2006). However, in-situ experimental measurements of n indicate that it takes values as low as unity without affecting the observed orientation of melt bands. Viscous anisotropy provides an alternative explanation for the observed band angles. It is produced by the stress-induced microstructural anisotropy (Daines and Kohlstedt, 1997; Zimmermann et al., 1999; Takei, 2010), and it enhances the coupling between melt migration and matrix shear deformation (Takei and Holtzman, 2009). Even without any porosity perturbation, viscous anisotropy destabilizes simple patterns of two-phase flow with a stress/strain gradient (eg., Poiseuille flow, torsional flow) and gives rise to shear-induced melt localization: the growth rate of this mechanism depends on the shear strain rate and the compaction length relative to the spatial scale of the gradient. When a porosity perturbation is added to the anisotropic system, both localization mechanisms work simultaneously, where the dominant angle of perturbation is decreased by the viscous anisotropy, similarly to the effect of n. Although viscous anisotropy plays an important role in melt localization, previous studies were limited to some simple or linearized cases (Takei and Holtzman, 2009, Butler 2012). Using linearised stability analysis and numerical simulation, we perform a systematic study of viscous anisotropy for behavior of partially molten rocks under forced deformation. Fully nonlinear solutions are obtained for melt localization under simple shear flow, 2D Poiseuille flow, and torsional flow. We show that Poiseuille flow causes melt-lubrication instability, but torsional flow does not. Results for simple shear and torsional flow are compared to the experimental results. Through the comparison between model predictions and experiments, we can test the validity of current theory, ascertain its deficiencies, and refine it to better describe the natural system.

A Simple Experimental Setup to Clearly Show that Light Does Not Recombine After Passing Through Two Prisms

NASA Astrophysics Data System (ADS)

Garcia-Molina, Rafael; del Mazo, Alejandro; Velasco, Santiago

2018-01-01

We present a simple and cheap experimental setup that clearly shows how the colors of the white light spectrum after passing a prism do not recombine when emerging from an identical second prism, as it is still found in many references.

A Simple Experimental Setup to Clearly Show That Light Does Not Recombine after Passing through Two Prisms

ERIC Educational Resources Information Center

Garcia-Molina, Rafael; del Mazo, Alejandro; Velasco, Santiago

2018-01-01

We present a simple and cheap experimental setup that clearly shows how the colors of the white light spectrum after passing a prism do not recombine when emerging from an identical second prism, as it is still found in many references.

Analytical and experimental study of vibrations in a gear transmission

NASA Technical Reports Server (NTRS)

Choy, F. K.; Ruan, Y. F.; Zakrajsek, J. J.; Oswald, Fred B.; Coy, J. J.

1991-01-01

An analytical simulation of the dynamics of a gear transmission system is presented and compared to experimental results from a gear noise test rig at the NASA Lewis Research Center. The analytical procedure developed couples the dynamic behaviors of the rotor-bearing-gear system with the response of the gearbox structure. The modal synthesis method is used in solving the overall dynamics of the system. Locally each rotor-gear stage is modeled as an individual rotor-bearing system using the matrix transfer technique. The dynamics of each individual rotor are coupled with other rotor stages through the nonlinear gear mesh forces and with the gearbox structure through bearing support systems. The modal characteristics of the gearbox structure are evaluated using the finite element procedure. A variable time steping integration routine is used to calculate the overall time transient behavior of the system in modal coordinates. The global dynamic behavior of the system is expressed in a generalized coordinate system. Transient and steady state vibrations of the gearbox system are presented in the time and frequency domains. The vibration characteristics of a simple single mesh gear noise test rig is modeled. The numerical simulations are compared to experimental data measured under typical operating conditions. The comparison of system natural frequencies, peak vibration amplitudes, and gear mesh frequencies are generally in good agreement.

Real-time scheduling using minimum search

NASA Technical Reports Server (NTRS)

Tadepalli, Prasad; Joshi, Varad

1992-01-01

In this paper we consider a simple model of real-time scheduling. We present a real-time scheduling system called RTS which is based on Korf's Minimin algorithm. Experimental results show that the schedule quality initially improves with the amount of look-ahead search and tapers off quickly. So it sppears that reasonably good schedules can be produced with a relatively shallow search.

In plane oscillation of a bifilar pendulum

NASA Astrophysics Data System (ADS)

Hinrichsen, Peter F.

2016-11-01

The line tensions, the horizontal and vertical accelerations as well as the period of large angle oscillations parallel to the plane of a bifilar suspension are presented and have been experimentally investigated using strain gauges and a smart phone. This system has a number of advantages over the simple pendulum for studying large angle oscillations, and for measuring the acceleration due to gravity.

Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 2. Experimental Validation with Simple Mixtures and Actual Fermentation Broth

EPA Science Inventory

BACKGROUND: In Part1 of this work, a process integrating vapor stripping, vapor compression, and a vapor permeation membrane separation step, Membrane Assisted Vapor Stripping (MAVS), was predicted to produce energy savings compared to traditional distillation systems for separat...

An Easy-to-Build Remote Laboratory with Data Transfer Using the Internet School Experimental System

ERIC Educational Resources Information Center

Schauer, Frantisek; Lustig, Frantisek; Dvorak, Jiri; Ozvoldova, Miroslava

2008-01-01

The present state of information communication technology makes it possible to devise and run computer-based e-laboratories accessible to any user with a connection to the Internet, equipped with very simple technical means and making full use of web services. Thus, the way is open for a new strategy of physics education with strongly global…

Implementing quantum logic gates with gradient ascent pulse engineering: principles and practicalities.

PubMed

Rowland, Benjamin; Jones, Jonathan A

2012-10-13

We briefly describe the use of gradient ascent pulse engineering (GRAPE) pulses to implement quantum logic gates in nuclear magnetic resonance quantum computers, and discuss a range of simple extensions to the core technique. We then consider a range of difficulties that can arise in practical implementations of GRAPE sequences, reflecting non-idealities in the experimental systems used.

Digital image compression for a 2f multiplexing optical setup

NASA Astrophysics Data System (ADS)

Vargas, J.; Amaya, D.; Rueda, E.

2016-07-01

In this work a virtual 2f multiplexing system was implemented in combination with digital image compression techniques and redundant information elimination. Depending on the image type to be multiplexed, a memory-usage saving of as much as 99% was obtained. The feasibility of the system was tested using three types of images, binary characters, QR codes, and grey level images. A multiplexing step was implemented digitally, while a demultiplexing step was implemented in a virtual 2f optical setup following real experimental parameters. To avoid cross-talk noise, each image was codified with a specially designed phase diffraction carrier that would allow the separation and relocation of the multiplexed images on the observation plane by simple light propagation. A description of the system is presented together with simulations that corroborate the method. The present work may allow future experimental implementations that will make use of all the parallel processing capabilities of optical systems.

An Intelligent and Interactive Simulation and Tutoring Environment for Exploring and Learning Simple Machines

NASA Astrophysics Data System (ADS)

Myneni, Lakshman Sundeep

Students in middle school science classes have difficulty mastering physics concepts such as energy and work, taught in the context of simple machines. Moreover, students' naive conceptions of physics often remain unchanged after completing a science class. To address this problem, I developed an intelligent tutoring system, called the Virtual Physics System (ViPS), which coaches students through problem solving with one class of simple machines, pulley systems. The tutor uses a unique cognitive based approach to teaching simple machines, and includes innovations in three areas. (1) It employs a teaching strategy that focuses on highlighting links among concepts of the domain that are essential for conceptual understanding yet are seldom learned by students. (2) Concepts are taught through a combination of effective human tutoring techniques (e.g., hinting) and simulations. (3) For each student, the system identifies which misconceptions he or she has, from a common set of student misconceptions gathered from domain experts, and tailors tutoring to match the correct line of scientific reasoning regarding the misconceptions. ViPS was implemented as a platform on which students can design and simulate pulley system experiments, integrated with a constraint-based tutor that intervenes when students make errors during problem solving to teach them and to help them. ViPS has a web-based client-server architecture, and has been implemented using Java technologies. ViPS is different from existing physics simulations and tutoring systems due to several original features. (1). It is the first system to integrate a simulation based virtual experimentation platform with an intelligent tutoring component. (2) It uses a novel approach, based on Bayesian networks, to help students construct correct pulley systems for experimental simulation. (3) It identifies student misconceptions based on a novel decision tree applied to student pretest scores, and tailors tutoring to individual students based on detected misconceptions. ViPS has been evaluated through usability and usefulness experiments with undergraduate engineering students taking their first college-level engineering physics course and undergraduate pre-service teachers taking their first college-level physics course. These experiments demonstrated that ViPS is highly usable and effective. Students using ViPS reduced their misconceptions, and students conducting virtual experiments in ViPS learned more than students who conducted experiments with physical pulley systems. Interestingly, it was also found that college students exhibited many of the same misconceptions that have been identified in middle school students.

An orbital angular momentum radio communication system optimized by intensity controlled masks effectively: Theoretical design and experimental verification

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

Gao, Xinlu; Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing 100875; Huang, Shanguo, E-mail: shghuang@bupt.edu.cn

A system of generating and receiving orbital angular momentum (OAM) radio beams, which are collectively formed by two circular array antennas (CAAs) and effectively optimized by two intensity controlled masks, is proposed and experimentally investigated. The scheme is effective in blocking of the unwanted OAM modes and enhancing the power of received radio signals, which results in the capacity gain of system and extended transmission distance of the OAM radio beams. The operation principle of the intensity controlled masks, which can be regarded as both collimator and filter, is feasible and simple to realize. Numerical simulations of intensity and phasemore » distributions at each key cross-sectional plane of the radio beams demonstrate the collimated results. The experimental results match well with the theoretical analysis and the receive distance of the OAM radio beam at radio frequency (RF) 20 GHz is extended up to 200 times of the wavelength of the RF signals, the measured distance is 5 times of the original measured distance. The presented proof-of-concept experiment demonstrates the feasibility of the system.« less

An Experimental Framework for Generating Evolvable Chemical Systems in the Laboratory

NASA Astrophysics Data System (ADS)

Baum, David A.; Vetsigian, Kalin

2017-12-01

Most experimental work on the origin of life has focused on either characterizing the chemical synthesis of particular biochemicals and their precursors or on designing simple chemical systems that manifest life-like properties such as self-propagation or adaptive evolution. Here we propose a new class of experiments, analogous to artificial ecosystem selection, where we select for spontaneously forming self-propagating chemical assemblages in the lab and then seek evidence of a response to that selection as a key indicator that life-like chemical systems have arisen. Since surfaces and surface metabolism likely played an important role in the origin of life, a key experimental challenge is to find conditions that foster nucleation and spread of chemical consortia on surfaces. We propose high-throughput screening of a diverse set of conditions in order to identify combinations of "food," energy sources, and mineral surfaces that foster the emergence of surface-associated chemical consortia that are capable of adaptive evolution. Identification of such systems would greatly advance our understanding of the emergence of self-propagating entities and the onset of adaptive evolution during the origin of life.

An Exploratory Data Analysis System for Support in Medical Decision-Making

PubMed Central

Copeland, J. A.; Hamel, B.; Bourne, J. R.

1979-01-01

An experimental system was developed to allow retrieval and analysis of data collected during a study of neurobehavioral correlates of renal disease. After retrieving data organized in a relational data base, simple bivariate statistics of parametric and nonparametric nature could be conducted. An “exploratory” mode in which the system provided guidance in selection of appropriate statistical analyses was also available to the user. The system traversed a decision tree using the inherent qualities of the data (e.g., the identity and number of patients, tests, and time epochs) to search for the appropriate analyses to employ.

Physical layer security in fiber-optic MIMO-SDM systems: An overview

NASA Astrophysics Data System (ADS)

Guan, Kyle; Cho, Junho; Winzer, Peter J.

2018-02-01

Fiber-optic transmission systems provide large capacities over enormous distances but are vulnerable to simple eavesdropping attacks at the physical layer. We classify key-based and keyless encryption and physical layer security techniques and discuss them in the context of optical multiple-input-multiple-output space-division multiplexed (MIMO-SDM) fiber-optic communication systems. We show that MIMO-SDM not only increases system capacity, but also ensures the confidentiality of information transmission. Based on recent numerical and experimental results, we review how the unique channel characteristics of MIMO-SDM can be exploited to provide various levels of physical layer security.

A Case Study on the Application of a Structured Experimental Method for Optimal Parameter Design of a Complex Control System

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo

2015-01-01

This report documents a case study on the application of Reliability Engineering techniques to achieve an optimal balance between performance and robustness by tuning the functional parameters of a complex non-linear control system. For complex systems with intricate and non-linear patterns of interaction between system components, analytical derivation of a mathematical model of system performance and robustness in terms of functional parameters may not be feasible or cost-effective. The demonstrated approach is simple, structured, effective, repeatable, and cost and time efficient. This general approach is suitable for a wide range of systems.

Transport and thermodynamic properties of hydrous melts in the system An-Di.

NASA Astrophysics Data System (ADS)

Giordano, D.; Potuzak, M.; Romano, C.; Russell, J. K.; Nowak, M.; Dingwell, D. B.

2006-12-01

The thermodynamic and transport properties hydrous silicate melts are of fundamental importance for characterization of the dynamics and energetics associated with silicate melts in the Earth. The literature concerning the transport and calorimetric properties of hydrous silicate melts remains scarce. With few exceptions little has been effectively done in order to provide chemical models that bridge the gap between the description of both complex and simple systems. The An-Di system is of general interest to geochemists as well as petrologists because it serves as a simple analogue for basaltic compositions. It was chosen here due to the combination of its simple chemical description and the presence of an extensive database of published experimental data on both its transport and thermodynamic properties. We have measured the viscosity (η)), the glass transition temperatures (Tg) and the heat capacity (Cp) of silicate melts in the An-Di system containing up to 3 wt.% of dissolved H2O. Viscosity data were obtained by using the dilatometric method of micropenetration, whereas a differential scanning calorimeter (DSC) was employed to determine the glass transition temperatures and the heat capacities. In order to characterize the well-known cooling/heating rate dependence of the glass transition temperatures the calorimetric measurements were performed at heating/cooling rate of 5, 10, 15 and 20 K/min. These results together with those of previous experimental studies have been used to provide a compositional model capable of calculating the Newtonian viscosity of melts as well as the Tg and Cp values for the An- Di+H2O system. The non-Arrhenian T-dependence of viscosity is accounted for by the Vogel-Fulcher- Tammann (VFT) and the Adam Gibbs (AG) equations. Our optimizations assume a common, high-T limit (A) for silicate melt viscosity, consistent with values provided by both theoretical and experimental studies. In particular, we also show that glass transition temperatures taken at each single heating/cooling rate are associated to single viscosity values. The equivalence of the activation energy associated to viscous and enthalpic relaxation process at specific temperatures also allow us to calibrate a tool to predict the viscosity of silicate melts by using specific heat curves. The effect of water on the heat capacity of the glass (Cpglass), from dry to nearly 3 wt% H2O, ranges from almost absent up to 20% of the measured Cp,glass values.

Statistical Models for Averaging of the Pump–Probe Traces: Example of Denoising in Terahertz Time-Domain Spectroscopy

NASA Astrophysics Data System (ADS)

Skorobogatiy, Maksim; Sadasivan, Jayesh; Guerboukha, Hichem

2018-05-01

In this paper, we first discuss the main types of noise in a typical pump-probe system, and then focus specifically on terahertz time domain spectroscopy (THz-TDS) setups. We then introduce four statistical models for the noisy pulses obtained in such systems, and detail rigorous mathematical algorithms to de-noise such traces, find the proper averages and characterise various types of experimental noise. Finally, we perform a comparative analysis of the performance, advantages and limitations of the algorithms by testing them on the experimental data collected using a particular THz-TDS system available in our laboratories. We conclude that using advanced statistical models for trace averaging results in the fitting errors that are significantly smaller than those obtained when only a simple statistical average is used.

Electrical percolation in the presence of attractive interactions: An effective medium lattice approach applied to microemulsion systems

NASA Astrophysics Data System (ADS)

Hattori, Y.; Ushiki, H.; Engl, W.; Courbin, L.; Panizza, P.

2005-08-01

Within the framework of an effective medium approach and a mean-field approximation, we present a simple lattice model to treat electrical percolation in the presence of attractive interactions. We show that the percolation line depends on the magnitude of interactions. In 2 dimensions, the percolation line meets the binodal line at the critical point. A good qualitative agreement is observed with experimental results on a ternary AOT-based water-in-oil microemulsion system.

Correlations in electrically coupled chaotic lasers.

PubMed

Rosero, E J; Barbosa, W A S; Martinez Avila, J F; Khoury, A Z; Rios Leite, J R

2016-09-01

We show how two electrically coupled semiconductor lasers having optical feedback can present simultaneous antiphase correlated fast power fluctuations, and strong in-phase synchronized spikes of chaotic power drops. This quite counterintuitive phenomenon is demonstrated experimentally and confirmed by numerical solutions of a deterministic dynamical system of rate equations. The occurrence of negative and positive cross correlation between parts of a complex system according to time scales, as proved in our simple arrangement, is relevant for the understanding and characterization of collective properties in complex networks.

Muon Beamline Commissioning and Feasibility Study for μSR at a New DC Muon Beamline, MuSIC-RCNP, Osaka University

NASA Astrophysics Data System (ADS)

Tomono, Dai; Fukuda, Mitsuhiro; Hatanaka, Kichiji; Higemoto, Wataru; Kawashima, Yoshitaka; Kojima, Kenji M.; Kuno, Yoshitaka; Matsuda, Yugo; Matsuzaki, Teiichiro; Miyake, Yasuhiro; Miyamoto, Koichiro; Morita, Yasuyuki; Motoishi, Takahiro; Nakazawa, Yu; Ninomiya, Kazuhiko; Nishikawa, Ryo; Ohta, Saki; Sato, Akira; Shimomura, Koichiro; Takahisa, Keiji; Weichao, Yao; Wong, Ming L.

At the new DC muon beamline MuSIC at Research Center for Nuclear Physics (RCNP), Osaka University, the beamline construction from the solenoid system of the muon production to the experimental port was completed. A beamline commissioning and a feasibility study for μSR are now in progress. With newly refurbished spectrometer installed at the experimental port, we succeeded in observing μSR spectra and μ-e decay asymmetry in a simple setup down to 4 K. We are still under development of other μSR appratuses.

Relativistic Few-Body Hadronic Physics Calculations

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

Polyzou, Wayne

2016-06-20

The goal of this research proposal was to use ``few-body'' methods to understand the structure and reactions of systems of interacting hadrons (neutrons, protons, mesons, quarks) over a broad range of energy scales. Realistic mathematical models of few-hadron systems have the advantage that they are sufficiently simple that they can be solved with mathematically controlled errors. These systems are also simple enough that it is possible to perform complete accurate experimental measurements on these systems. Comparison between theory and experiment puts strong constraints on the structure of the models. Even though these systems are ``simple'', both the experiments and computationsmore » push the limits of technology. The important property of ``few-body'' systems is that the ``cluster property'' implies that the interactions that appear in few-body systems are identical to the interactions that appear in complicated many-body systems. Of particular interest are models that correctly describe physics at distance scales that are sensitive to the internal structure of the individual nucleons. The Heisenberg uncertainty principle implies that in order to be sensitive to physics on distance scales that are a fraction of the proton or neutron radius, a relativistic treatment of quantum mechanics is necessary. The research supported by this grant involved 30 years of effort devoted to studying all aspects of interacting two and three-body systems. Realistic interactions were used to compute bound states of two- and three-nucleon, and two- and three-quark systems. Scattering observables for these systems were computed for a broad range of energies - from zero energy scattering to few GeV scattering, where experimental evidence of sub-nucleon degrees of freedom is beginning to appear. Benchmark calculations were produced, which when compared with calculations of other groups provided an essential check on these complicated calculations. In addition to computing bound state properties and scattering cross section, we also computed electron scattering cross sections in few-nucleon and few-quark systems, which are sensitive to the electric currents in these systems. We produced the definitive review on article on relativistic quantum mechanics, which and been used by many groups. In addition we developed and tested many computational techniques are used by other groups. Many of these techniques have applications in other areas of physics. The research benefited by collaborations with physicists from many different institutions and countries. It also involved working with seventeen undergraduate and graduate students.« less

Route to one-step microstructure mold fabrication for PDMS microfluidic chip

NASA Astrophysics Data System (ADS)

Lv, Xiaoqing; Geng, Zhaoxin; Fan, Zhiyuan; Wang, Shicai; Su, Yue; Fang, Weihao; Pei, Weihua; Chen, Hongda

2018-04-01

The microstructure mold fabrication for PDMS microfluidic chip remains complex and time-consuming process requiring special equipment and protocols: photolithography and etching. Thus, a rapid and cost-effective method is highly needed. Comparing with the traditional microfluidic chip fabricating process based on the micro-electromechanical system (MEMS), this method is simple and easy to implement, and the whole fabrication process only requires 1-2 h. Different size of microstructure from 100 to 1000 μm was fabricated, and used to culture four kinds of breast cancer cell lines. Cell viability and morphology was assessed when they were cultured in the micro straight channels, micro square holes and the bonding PDMS-glass microfluidic chip. The experimental results indicate that the microfluidic chip is good and meet the experimental requirements. This method can greatly reduce the process time and cost of the microfluidic chip, and provide a simple and effective way for the structure design and in the field of biological microfabrications and microfluidic chips.

Predicting ecosystem shifts requires new approaches that integrate the effects of climate change across entire systems

PubMed Central

Russell, Bayden D.; Harley, Christopher D. G.; Wernberg, Thomas; Mieszkowska, Nova; Widdicombe, Stephen; Hall-Spencer, Jason M.; Connell, Sean D.

2012-01-01

Most studies that forecast the ecological consequences of climate change target a single species and a single life stage. Depending on climatic impacts on other life stages and on interacting species, however, the results from simple experiments may not translate into accurate predictions of future ecological change. Research needs to move beyond simple experimental studies and environmental envelope projections for single species towards identifying where ecosystem change is likely to occur and the drivers for this change. For this to happen, we advocate research directions that (i) identify the critical species within the target ecosystem, and the life stage(s) most susceptible to changing conditions and (ii) the key interactions between these species and components of their broader ecosystem. A combined approach using macroecology, experimentally derived data and modelling that incorporates energy budgets in life cycle models may identify critical abiotic conditions that disproportionately alter important ecological processes under forecasted climates. PMID:21900317

Simple Organics and Biomonomers Identified in HCN Polymers: An Overview

PubMed Central

Ruiz-Bermejo, Marta; Zorzano, María-Paz; Osuna-Esteban, Susana

2013-01-01

Hydrogen cyanide (HCN) is a ubiquitous molecule in the Universe. It is a compound that is easily produced in significant yields in prebiotic simulation experiments using a reducing atmosphere. HCN can spontaneously polymerise under a wide set of experimental conditions. It has even been proposed that HCN polymers could be present in objects such as asteroids, moons, planets and, in particular, comets. Moreover, it has been suggested that these polymers could play an important role in the origin of life. In this review, the simple organics and biomonomers that have been detected in HCN polymers, the analytical techniques and procedures that have been used to detect and characterise these molecules and an exhaustive classification of the experimental/environmental conditions that favour the formation of HCN polymers are summarised. Nucleobases, amino acids, carboxylic acids, cofactor derivatives and other compounds have been identified in HCN polymers. The great molecular diversity found in HCN polymers encourages their placement at the central core of a plausible protobiological system. PMID:25369814

On the context-dependent scaling of consumer feeding rates.

PubMed

Barrios-O'Neill, Daniel; Kelly, Ruth; Dick, Jaimie T A; Ricciardi, Anthony; MacIsaac, Hugh J; Emmerson, Mark C

2016-06-01

The stability of consumer-resource systems can depend on the form of feeding interactions (i.e. functional responses). Size-based models predict interactions - and thus stability - based on consumer-resource size ratios. However, little is known about how interaction contexts (e.g. simple or complex habitats) might alter scaling relationships. Addressing this, we experimentally measured interactions between a large size range of aquatic predators (4-6400 mg over 1347 feeding trials) and an invasive prey that transitions among habitats: from the water column (3D interactions) to simple and complex benthic substrates (2D interactions). Simple and complex substrates mediated successive reductions in capture rates - particularly around the unimodal optimum - and promoted prey population stability in model simulations. Many real consumer-resource systems transition between 2D and 3D interactions, and along complexity gradients. Thus, Context-Dependent Scaling (CDS) of feeding interactions could represent an unrecognised aspect of food webs, and quantifying the extent of CDS might enhance predictive ecology. © The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Simple effective rule to estimate the jamming packing fraction of polydisperse hard spheres.

PubMed

Santos, Andrés; Yuste, Santos B; López de Haro, Mariano; Odriozola, Gerardo; Ogarko, Vitaliy

2014-04-01

A recent proposal in which the equation of state of a polydisperse hard-sphere mixture is mapped onto that of the one-component fluid is extrapolated beyond the freezing point to estimate the jamming packing fraction ϕJ of the polydisperse system as a simple function of M1M3/M22, where Mk is the kth moment of the size distribution. An analysis of experimental and simulation data of ϕJ for a large number of different mixtures shows a remarkable general agreement with the theoretical estimate. To give extra support to the procedure, simulation data for seventeen mixtures in the high-density region are used to infer the equation of state of the pure hard-sphere system in the metastable region. An excellent collapse of the inferred curves up to the glass transition and a significant narrowing of the different out-of-equilibrium glass branches all the way to jamming are observed. Thus, the present approach provides an extremely simple criterion to unify in a common framework and to give coherence to data coming from very different polydisperse hard-sphere mixtures.

RESEARCH AREA 7.1: Exploring the Systematics of Controlling Quantum Phenomena

DTIC Science & Technology

2016-10-05

the bottom to the top of the landscape. Computational analyses for simple model quantum systems are performed to ascertain the relative abundance of...SECURITY CLASSIFICATION OF: This research is concerned with the theoretical and experimental control quantum dynamics phenomena. Advances include new...algorithms to accelerate quantum control as well as provide physical insights into the controlled dynamics. The latter research includes the

Volume II: Compendium Abstracts

DTIC Science & Technology

2008-08-01

project developed a fast and simple method of characterization for ceramic , polymer composite, and ceramic -composite materials systems. Current methods...incrementally at 1-inch intervals and displayed as a false-color image map of the sample. This experimental setup can be easily scaled from single ceramic ...low-power, high-force characteristics of lead zirconate titanate ( PZT ) and an offset-beam design to achieve rotational or near-linear translational

Cycle frequency in standard Rock-Paper-Scissors games: Evidence from experimental economics

NASA Astrophysics Data System (ADS)

Xu, Bin; Zhou, Hai-Jun; Wang, Zhijian

2013-10-01

The Rock-Paper-Scissors (RPS) game is a widely used model system in game theory. Evolutionary game theory predicts the existence of persistent cycles in the evolutionary trajectories of the RPS game, but experimental evidence has remained to be rather weak. In this work, we performed laboratory experiments on the RPS game and analyzed the social-state evolutionary trajectories of twelve populations of N=6 players. We found strong evidence supporting the existence of persistent cycles. The mean cycling frequency was measured to be 0.029±0.009 period per experimental round. Our experimental observations can be quantitatively explained by a simple non-equilibrium model, namely the discrete-time logit dynamical process with a noise parameter. Our work therefore favors the evolutionary game theory over the classical game theory for describing the dynamical behavior of the RPS game.

Modelling the complete operation of a free-piston shock tunnel for a low enthalpy condition

NASA Astrophysics Data System (ADS)

McGilvray, M.; Dann, A. G.; Jacobs, P. A.

2013-07-01

Only a limited number of free-stream flow properties can be measured in hypersonic impulse facilities at the nozzle exit. This poses challenges for experimenters when subsequently analysing experimental data obtained from these facilities. Typically in a reflected shock tunnel, a simple analysis that requires small amounts of computational resources is used to calculate quasi-steady gas properties. This simple analysis requires initial fill conditions and experimental measurements in analytical calculations of each major flow process, using forward coupling with minor corrections to include processes that are not directly modeled. However, this simplistic approach leads to an unknown level of discrepancy to the true flow properties. To explore the simple modelling techniques accuracy, this paper details the use of transient one and two-dimensional numerical simulations of a complete facility to obtain more refined free-stream flow properties from a free-piston reflected shock tunnel operating at low-enthalpy conditions. These calculations were verified by comparison to experimental data obtained from the facility. For the condition and facility investigated, the test conditions at nozzle exit produced with the simple modelling technique agree with the time and space averaged results from the complete facility calculations to within the accuracy of the experimental measurements.

A Simple and Low-Cost Monitoring System to Investigate Environmental Conditions in a Biological Research Laboratory

PubMed Central

Gurdita, Akshay; Vovko, Heather; Ungrin, Mark

2016-01-01

Basic equipment such as incubation and refrigeration systems plays a critical role in nearly all aspects of the traditional biological research laboratory. Their proper functioning is therefore essential to ensure reliable and repeatable experimental results. Despite this fact, in many academic laboratories little attention is paid to validating and monitoring their function, primarily due to the cost and/or technical complexity of available commercial solutions. We have therefore developed a simple and low-cost monitoring system that combines a “Raspberry Pi” single-board computer with USB-connected sensor interfaces to track and log parameters such as temperature and pressure, and send email alert messages as appropriate. The system is controlled by open-source software, and we have also generated scripts to automate software setup so that no background in programming is required to install and use it. We have applied it to investigate the behaviour of our own equipment, and present here the results along with the details of the monitoring system used to obtain them. PMID:26771659

Design and implementation of a Sun tracker with a dual-axis single motor for an optical sensor-based photovoltaic system.

PubMed

Wang, Jing-Min; Lu, Chia-Liang

2013-03-06

The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV) system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR) sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications.

Design and Implementation of a Sun Tracker with a Dual-Axis Single Motor for an Optical Sensor-Based Photovoltaic System

PubMed Central

Wang, Jing-Min; Lu, Chia-Liang

2013-01-01

The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV) system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR) sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications. PMID:23467030

Radiation/Catalytic Augmented Combustion.

DTIC Science & Technology

1984-05-01

interest to compare the experimental results for the solid bluff body with a thuoretical result. Using simple argtinieiiLs from fluid mechanics " one...responsibility through completion. Dr. A. E. Cerkanowlcz assisted in writing this final report. Experimental studies on catalytic augmented combustion...as well as with other combustion species, lead to ignition and sustained combustion via chain reactions. Simple combustion enhancement without

Experimental Evaluation of the Drag Coefficient of Water Rockets by a Simple Free-Fall Test

ERIC Educational Resources Information Center

Barrio-Perotti, R.; Blanco-Marigorta, E. Arguelles-Diaz, K.; Fernandez-Oro, J.

2009-01-01

The flight trajectory of a water rocket can be reasonably calculated if the magnitude of the drag coefficient is known. The experimental determination of this coefficient with enough precision is usually quite difficult, but in this paper we propose a simple free-fall experiment for undergraduate students to reasonably estimate the drag…

A simple theoretical framework for understanding heterogeneous differentiation of CD4+ T cells

PubMed Central

2012-01-01

Background CD4+ T cells have several subsets of functional phenotypes, which play critical yet diverse roles in the immune system. Pathogen-driven differentiation of these subsets of cells is often heterogeneous in terms of the induced phenotypic diversity. In vitro recapitulation of heterogeneous differentiation under homogeneous experimental conditions indicates some highly regulated mechanisms by which multiple phenotypes of CD4+ T cells can be generated from a single population of naïve CD4+ T cells. Therefore, conceptual understanding of induced heterogeneous differentiation will shed light on the mechanisms controlling the response of populations of CD4+ T cells under physiological conditions. Results We present a simple theoretical framework to show how heterogeneous differentiation in a two-master-regulator paradigm can be governed by a signaling network motif common to all subsets of CD4+ T cells. With this motif, a population of naïve CD4+ T cells can integrate the signals from their environment to generate a functionally diverse population with robust commitment of individual cells. Notably, two positive feedback loops in this network motif govern three bistable switches, which in turn, give rise to three types of heterogeneous differentiated states, depending upon particular combinations of input signals. We provide three prototype models illustrating how to use this framework to explain experimental observations and make specific testable predictions. Conclusions The process in which several types of T helper cells are generated simultaneously to mount complex immune responses upon pathogenic challenges can be highly regulated, and a simple signaling network motif can be responsible for generating all possible types of heterogeneous populations with respect to a pair of master regulators controlling CD4+ T cell differentiation. The framework provides a mathematical basis for understanding the decision-making mechanisms of CD4+ T cells, and it can be helpful for interpreting experimental results. Mathematical models based on the framework make specific testable predictions that may improve our understanding of this differentiation system. PMID:22697466

Object localization through the lateral line system of fish: theory and experiment.

PubMed

Goulet, Julie; Engelmann, Jacob; Chagnaud, Boris P; Franosch, Jan-Moritz P; Suttner, Maria D; van Hemmen, J Leo

2008-01-01

Fish acquire information about their aquatic environment by means of their mechanosensory lateral-line system. This system consists of superficial and canal neuromasts that sense perturbations in the water surrounding them. Based on a hydrodynamic model presented here, we propose a mechanism through which fish can localize the source of these perturbations. In doing so we include the curvature of the fish body, a realistic lateral line canal inter-pore distance for the lateral-line canals, and the surface boundary layer. Using our model to explore receptor behavior based on experimental data of responses to dipole stimuli we suggest that superficial and canal neuromasts employ the same mechanism, hence provide the same type of input to the central nervous system. The analytical predictions agree well with spiking responses recorded experimentally from primary lateral-line nerve fibers. From this, and taking into account the central organization of the lateral-line system, we present a simple biophysical model for determining the distance to a source.

Experimental recovery of quantum correlations in absence of system-environment back-action

PubMed Central

Xu, Jin-Shi; Sun, Kai; Li, Chuan-Feng; Xu, Xiao-Ye; Guo, Guang-Can; Andersson, Erika; Lo Franco, Rosario; Compagno, Giuseppe

2013-01-01

Revivals of quantum correlations in composite open quantum systems are a useful dynamical feature against detrimental effects of the environment. Their occurrence is attributed to flows of quantum information back and forth from systems to quantum environments. However, revivals also show up in models where the environment is classical, thus unable to store quantum correlations, and forbids system-environment back-action. This phenomenon opens basic issues about its interpretation involving the role of classical environments, memory effects, collective effects and system-environment correlations. Moreover, an experimental realization of back-action-free quantum revivals has applicative relevance as it leads to recover quantum resources without resorting to more demanding structured environments and correction procedures. Here we introduce a simple two-qubit model suitable to address these issues. We then report an all-optical experiment which simulates the model and permits us to recover and control, against decoherence, quantum correlations without back-action. We finally give an interpretation of the phenomenon by establishing the roles of the involved parties. PMID:24287554

Experimental recovery of quantum correlations in absence of system-environment back-action.

PubMed

Xu, Jin-Shi; Sun, Kai; Li, Chuan-Feng; Xu, Xiao-Ye; Guo, Guang-Can; Andersson, Erika; Lo Franco, Rosario; Compagno, Giuseppe

2013-01-01

Revivals of quantum correlations in composite open quantum systems are a useful dynamical feature against detrimental effects of the environment. Their occurrence is attributed to flows of quantum information back and forth from systems to quantum environments. However, revivals also show up in models where the environment is classical, thus unable to store quantum correlations, and forbids system-environment back-action. This phenomenon opens basic issues about its interpretation involving the role of classical environments, memory effects, collective effects and system-environment correlations. Moreover, an experimental realization of back-action-free quantum revivals has applicative relevance as it leads to recover quantum resources without resorting to more demanding structured environments and correction procedures. Here we introduce a simple two-qubit model suitable to address these issues. We then report an all-optical experiment which simulates the model and permits us to recover and control, against decoherence, quantum correlations without back-action. We finally give an interpretation of the phenomenon by establishing the roles of the involved parties.

MARIKA - A model revision system using qualitative analysis of simulations. [of human orientation system

NASA Technical Reports Server (NTRS)

Groleau, Nicolas; Frainier, Richard; Colombano, Silvano; Hazelton, Lyman; Szolovits, Peter

1993-01-01

This paper describes portions of a novel system called MARIKA (Model Analysis and Revision of Implicit Key Assumptions) to automatically revise a model of the normal human orientation system. The revision is based on analysis of discrepancies between experimental results and computer simulations. The discrepancies are calculated from qualitative analysis of quantitative simulations. The experimental and simulated time series are first discretized in time segments. Each segment is then approximated by linear combinations of simple shapes. The domain theory and knowledge are represented as a constraint network. Incompatibilities detected during constraint propagation within the network yield both parameter and structural model alterations. Interestingly, MARIKA diagnosed a data set from the Massachusetts Eye and Ear Infirmary Vestibular Laboratory as abnormal though the data was tagged as normal. Published results from other laboratories confirmed the finding. These encouraging results could lead to a useful clinical vestibular tool and to a scientific discovery system for space vestibular adaptation.

A discrete-time adaptive control scheme for robot manipulators

NASA Technical Reports Server (NTRS)

Tarokh, M.

1990-01-01

A discrete-time model reference adaptive control scheme is developed for trajectory tracking of robot manipulators. The scheme utilizes feedback, feedforward, and auxiliary signals, obtained from joint angle measurement through simple expressions. Hyperstability theory is utilized to derive the adaptation laws for the controller gain matrices. It is shown that trajectory tracking is achieved despite gross robot parameter variation and uncertainties. The method offers considerable design flexibility and enables the designer to improve the performance of the control system by adjusting free design parameters. The discrete-time adaptation algorithm is extremely simple and is therefore suitable for real-time implementation. Simulations and experimental results are given to demonstrate the performance of the scheme.

Simplified, inverse, ejector design tool

NASA Technical Reports Server (NTRS)

Dechant, Lawrence J.

1993-01-01

A simple lumped parameter based inverse design tool has been developed which provides flow path geometry and entrainment estimates subject to operational, acoustic, and design constraints. These constraints are manifested through specification of primary mass flow rate or ejector thrust, fully-mixed exit velocity, and static pressure matching. Fundamentally, integral forms of the conservation equations coupled with the specified design constraints are combined to yield an easily invertible linear system in terms of the flow path cross-sectional areas. Entrainment is computed by back substitution. Initial comparison with experimental and analogous one-dimensional methods show good agreement. Thus, this simple inverse design code provides an analytically based, preliminary design tool with direct application to High Speed Civil Transport (HSCT) design studies.

Tunable, Flexible and Efficient Optimization of Control Pulses for Superconducting Qubits, part I - Theory

NASA Astrophysics Data System (ADS)

Machnes, Shai; AsséMat, Elie; Tannor, David; Wilhelm, Frank

Quantum computation places very stringent demands on gate fidelities, and experimental implementations require both the controls and the resultant dynamics to conform to hardware-specific ansatzes and constraints. Superconducting qubits present the additional requirement that pulses have simple parametrizations, so they can be further calibrated in the experiment, to compensate for uncertainties in system characterization. We present a novel, conceptually simple and easy-to-implement gradient-based optimal control algorithm, GOAT, which satisfies all the above requirements. In part II we shall demonstrate the algorithm's capabilities, by using GOAT to optimize fast high-accuracy pulses for two leading superconducting qubits architectures - Xmons and IBM's flux-tunable couplers.

Chemotaxis and auto-chemotaxis of self-propelling artificial droplet swimmers

NASA Astrophysics Data System (ADS)

Jin, Chenyu; Krueger, Carsten; Maass, Corinna

Chemotaxis and auto-chemotaxis are key mechanisms in the dynamics of micro-organisms, e.g. in the acquisition of nutrients and in the communication between individuals, influencing the collective behavior. However, chemical signalling and the natural environment of biological swimmers are generally complex, making them hard to access analytically. Simple experimental systems showing similar features could provide vital insights. We present such a swimmer system, as well as controlled assays to study chemotactic effects quantitatively and reproducibly. In our experiments, we let auto-chemotactic droplet swimmers pass through bifurcating microfluidic channels and record anticorrelations between the branch choices of consecutive droplets. We present an analytical model based on balancing stochastic forces versus a diffusing chemical gradient matching the experimental data. supported by the DFG SPP 1726 ''Microswimmers'' and the MaxSynBio network.

Bistable metamaterial for switching and cascading elastic vibrations

PubMed Central

Foehr, André; Daraio, Chiara

2017-01-01

The realization of acoustic devices analogous to electronic systems, like diodes, transistors, and logic elements, suggests the potential use of elastic vibrations (i.e., phonons) in information processing, for example, in advanced computational systems, smart actuators, and programmable materials. Previous experimental realizations of acoustic diodes and mechanical switches have used nonlinearities to break transmission symmetry. However, existing solutions require operation at different frequencies or involve signal conversion in the electronic or optical domains. Here, we show an experimental realization of a phononic transistor-like device using geometric nonlinearities to switch and amplify elastic vibrations, via magnetic coupling, operating at a single frequency. By cascading this device in a tunable mechanical circuit board, we realize the complete set of mechanical logic elements and interconnect selected ones to execute simple calculations. PMID:28416663

Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

PubMed Central

Gu, Lingling; Luo, Yong; Han, Xuedong

2014-01-01

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation. PMID:24883405

Investigation of a new flux-modulated permanent magnet brushless motor for EVs.

PubMed

Fan, Ying; Gu, Lingling; Luo, Yong; Han, Xuedong; Cheng, Ming

2014-01-01

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

A network thermodynamic method for numerical solution of the Nernst-Planck and Poisson equation system with application to ionic transport through membranes.

PubMed

Horno, J; González-Caballero, F; González-Fernández, C F

1990-01-01

Simple techniques of network thermodynamics are used to obtain the numerical solution of the Nernst-Planck and Poisson equation system. A network model for a particular physical situation, namely ionic transport through a thin membrane with simultaneous diffusion, convection and electric current, is proposed. Concentration and electric field profiles across the membrane, as well as diffusion potential, have been simulated using the electric circuit simulation program, SPICE. The method is quite general and extremely efficient, permitting treatments of multi-ion systems whatever the boundary and experimental conditions may be.

Relative Navigation for Formation Flying of Spacecraft

NASA Technical Reports Server (NTRS)

Alonso, Roberto; Du, Ju-Young; Hughes, Declan; Junkins, John L.; Crassidis, John L.

2001-01-01

This paper presents a robust and efficient approach for relative navigation and attitude estimation of spacecraft flying in formation. This approach uses measurements from a new optical sensor that provides a line of sight vector from the master spacecraft to the secondary satellite. The overall system provides a novel, reliable, and autonomous relative navigation and attitude determination system, employing relatively simple electronic circuits with modest digital signal processing requirements and is fully independent of any external systems. Experimental calibration results are presented, which are used to achieve accurate line of sight measurements. State estimation for formation flying is achieved through an optimal observer design. Also, because the rotational and translational motions are coupled through the observation vectors, three approaches are suggested to separate both signals just for stability analysis. Simulation and experimental results indicate that the combined sensor/estimator approach provides accurate relative position and attitude estimates.

Experimental Analysis of Detergency Phenomena and Investigation of a Next-generation Detergency System.

PubMed

Gotoh, Keiko

2017-01-01

The detergency of products, mainly textiles, was evaluated using various experimental systems and discussed from the viewpoint of interfacial phenomena. The detergency phenomena observed for geometrically simple model systems were explained in terms of the total potential energy of interaction between the soil and the substrate, which was calculated as the sum of the electrical double layer, Lifshitzvan der Waals, and acid-base interactions using electrokinetic potentials and surface free energy components. Cleaning experiments using artificially soiled fabrics were performed using electro-osmotic flow and ultrasound as mechanical actions for soil removal, and the results were compared with those obtained with mechanical actions commonly used in textile washing. Simultaneous hydrophilization of the substrate and soil by an atmospheric pressure plasma jet remarkably improved the detergency in aqueous solutions. The application of the atmospheric pressure plasma jet to anti-fouling textiles was also proposed.

An experimental system for spectral line ratio measurements in the TJ-II stellarator.

PubMed

Zurro, B; Baciero, A; Fontdecaba, J M; Peláez, R; Jiménez-Rey, D

2008-10-01

The chord-integrated emissions of spectral lines have been monitored in the TJ-II stellarator by using a spectral system with time and space scanning capabilities and relative calibration over the entire UV-visible spectral range. This system has been used to study the line ratio of lines of different ionization stages of carbon (C(5+) 5290 A and C(4+) 2271 A) for plasma diagnostic purposes. The local emissivity of these ions has been reconstructed, for quasistationary profiles, by means of the inversion Fisher method described previously. The experimental line ratio is being empirically studied and in parallel a simple spectroscopic model has been developed to account for that ratio. We are investigating whether the role played by charge exchange processes with neutrals and the existence of non-Maxwellian electrons, intrinsic to Electron Cyclotron Resonance Heating (ECRH) heating, leave any distinguishable mark on this diagnostic method.

Underwater Turbulence Detection Using Gated Wavefront Sensing Technique

PubMed Central

Bi, Ying; Xu, Xiping; Chow, Eddy Mun Tik

2018-01-01

Laser sensing has been applied in various underwater applications, ranging from underwater detection to laser underwater communications. However, there are several great challenges when profiling underwater turbulence effects. Underwater detection is greatly affected by the turbulence effect, where the acquired image suffers excessive noise, blurring, and deformation. In this paper, we propose a novel underwater turbulence detection method based on a gated wavefront sensing technique. First, we elaborate on the operating principle of gated wavefront sensing and wavefront reconstruction. We then setup an experimental system in order to validate the feasibility of our proposed method. The effect of underwater turbulence on detection is examined at different distances, and under different turbulence levels. The experimental results obtained from our gated wavefront sensing system indicate that underwater turbulence can be detected and analyzed. The proposed gated wavefront sensing system has the advantage of a simple structure and high detection efficiency for underwater environments. PMID:29518889

Incremental wind tunnel testing of high lift systems

NASA Astrophysics Data System (ADS)

Victor, Pricop Mihai; Mircea, Boscoianu; Daniel-Eugeniu, Crunteanu

2016-06-01

Efficiency of trailing edge high lift systems is essential for long range future transport aircrafts evolving in the direction of laminar wings, because they have to compensate for the low performance of the leading edge devices. Modern high lift systems are subject of high performance requirements and constrained to simple actuation, combined with a reduced number of aerodynamic elements. Passive or active flow control is thus required for the performance enhancement. An experimental investigation of reduced kinematics flap combined with passive flow control took place in a low speed wind tunnel. The most important features of the experimental setup are the relatively large size, corresponding to a Reynolds number of about 2 Million, the sweep angle of 30 degrees corresponding to long range airliners with high sweep angle wings and the large number of flap settings and mechanical vortex generators. The model description, flap settings, methodology and results are presented.

Concentration of solar radiation by white painted transparent plates.

PubMed

Smestad, G; Hamill, P

1982-04-01

A simple flat-plate solar concentrator is described in this paper. The device is composed of a white painted transparent plate with a photovoltaic cell fixed to an unpainted area on the bottom of the plate. Light scattering off the white material is either lost or directed to the solar cell. Experimental concentrations of up to 1.9 times the incident solar flux have been achieved using white clays. These values are close to those predicted by theory for the experimental parameters investigated. A theory of the device operation is developed. Using this theory suggestions are made for optimizing the concentrator system. For reasonable choices of cell and plate size and reflectivities of 80% concentrations of over 2x are possible. The concentrator has the advantage over other systems in that the concentration is independent of incidence angle and the concentrator is easy to produce. The device needs no tracking system and will concentrate on a cloudy day.

Experimental Determination of Demand Response Control Models and Cost of Control for Ensembles of Window-Mount Air Conditioners

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

Geller, Drew Adam; Backhaus, Scott N.

Control of consumer electrical devices for providing electrical grid services is expanding in both the scope and the diversity of loads that are engaged in control, but there are few experimentally-based models of these devices suitable for control designs and for assessing the cost of control. A laboratory-scale test system is developed to experimentally evaluate the use of a simple window-mount air conditioner for electrical grid regulation services. The experimental test bed is a single, isolated air conditioner embedded in a test system that both emulates the thermodynamics of an air conditioned room and also isolates the air conditioner frommore » the real-world external environmental and human variables that perturb the careful measurements required to capture a model that fully characterizes both the control response functions and the cost of control. The control response functions and cost of control are measured using harmonic perturbation of the temperature set point and a test protocol that further isolates the air conditioner from low frequency environmental variability.« less

Experimental QR code optical encryption: noise-free data recovering.

PubMed

Barrera, John Fredy; Mira-Agudelo, Alejandro; Torroba, Roberto

2014-05-15

We report, to our knowledge for the first time, the experimental implementation of a quick response (QR) code as a "container" in an optical encryption system. A joint transform correlator architecture in an interferometric configuration is chosen as the experimental scheme. As the implementation is not possible in a single step, a multiplexing procedure to encrypt the QR code of the original information is applied. Once the QR code is correctly decrypted, the speckle noise present in the recovered QR code is eliminated by a simple digital procedure. Finally, the original information is retrieved completely free of any kind of degradation after reading the QR code. Additionally, we propose and implement a new protocol in which the reception of the encrypted QR code and its decryption, the digital block processing, and the reading of the decrypted QR code are performed employing only one device (smartphone, tablet, or computer). The overall method probes to produce an outcome far more attractive to make the adoption of the technique a plausible option. Experimental results are presented to demonstrate the practicality of the proposed security system.

Simple online recognition of optical data strings based on conservative optical logic

NASA Astrophysics Data System (ADS)

Caulfield, H. John; Shamir, Joseph; Zavalin, Andrey I.; Silberman, Enrique; Qian, Lei; Vikram, Chandra S.

2006-06-01

Optical packet switching relies on the ability of a system to recognize header information on an optical signal. Unless the headers are very short with large Hamming distances, optical correlation fails and optical logic becomes attractive because it can handle long headers with Hamming distances as low as 1. Unfortunately, the only optical logic gates fast enough to keep up with current communication speeds involve semiconductor optical amplifiers and do not lend themselves to the incorporation of large numbers of elements for header recognition and would consume a lot of power as well. The ideal system would operate at any bandwidth with no power consumption. We describe how to design and build such a system by using passive optical logic. This too leads to practical problems that we discuss. We show theoretically various ways to use optical interferometric logic for reliable recognition of long data streams such as headers in optical communication. In addition, we demonstrate one particularly simple experimental approach using interferometric coinc gates.

An Alternative Derivation of the Energy Levels of the "Particle on a Ring" System

NASA Astrophysics Data System (ADS)

Vincent, Alan

1996-10-01

All acceptable wave functions must be continuous mathematical functions. This criterion limits the acceptable functions for a particle in a linear 1-dimensional box to sine functions. If, however, the linear box is bent round into a ring, acceptable wave functions are those which are continuous at the 'join'. On this model some acceptable linear functions become unacceptable for the ring and some unacceptable cosine functions become acceptable. This approach can be used to produce a straightforward derivation of the energy levels and wave functions of the particle on a ring. These simple wave mechanical systems can be used as models of linear and cyclic delocalised systems such as conjugated hydrocarbons or the benzene ring. The promotion energy of an electron can then be used to calculate the wavelength of absorption of uv light. The simple model gives results of the correct order of magnitude and shows that, as the chain length increases, the uv maximum moves to longer wavelengths, as found experimentally.

The effect of the configuration of a single electrode corona discharge on its acoustic characteristics

NASA Astrophysics Data System (ADS)

Zhu, Xinlei; Zhang, Liancheng; Huang, Yifan; Wang, Jin; Liu, Zhen; Yan, Keping

2017-07-01

A new sparker system based on pulsed spark discharge with a single electrode has already been utilized for oceanic seismic exploration. However, the electro-acoustic energy efficiency of this system is lower than that of arc discharge based systems. A simple electrode structure was investigated in order to improve the electro-acoustic energy efficiency of the spark discharge. Experiments were carried out on an experimental setup with discharge in water driven by a pulsed power source. The voltage-current waveform, acoustic signal and bubble oscillation were recorded when the relative position of the electrode varied. The electro-acoustic energy efficiency was also calculated. The load voltage had a saltation for the invaginated electrode tip, namely an obvious voltage remnant. The more the electrode tip was invaginated, the larger the pressure peaks and first period became. The results show that electrode recessing into the insulating layer is a simple and effective way to improve the electro-acoustic energy efficiency from 2% to about 4%.

Postreceptoral chromatic-adaptation mechanisms in the red-green and blue-yellow systems using simple reaction times

NASA Astrophysics Data System (ADS)

Medina, José M.; Díaz, José A.

2006-05-01

Simple visual-reaction times (VRT) were measured for a variety of stimuli selected along red-green (L-M axis) and blue-yellow [S-(L+M) axis] directions in the isoluminant plane under different adaptation stimuli. Data were plotted in terms of the RMS cone contrast in contrast-threshold units. For each opponent system, a modified Piéron function was fitted in each experimental configuration and on all adaptation stimuli. A single function did not account for all the data, confirming the existence of separate postreceptoral adaptation mechanisms in each opponent system under suprathreshold conditions. The analysis of the VRT-hazard functions suggested that both color-opponent mechanisms present a well-defined, transient-sustained structure at marked suprathreshold conditions. The influence of signal polarity and chromatic adaptation on each color axis proves the existence of asymmetries in the integrated hazard functions, suggesting separate detection mechanisms for each pole (red, green, blue, and yellow detectors).

Mechanical system diagnostics using vibration testing techniques

NASA Technical Reports Server (NTRS)

Mcleod, Catherine D.; Raju, P. K.; Crocker, M. J.

1990-01-01

The 'Cepstrum' technique of vibration-path identification allows the recovery of the transfer function of a system with little knowledge as to its excitation force, by means of a mathematical manipulation of the system output in conjunction with subtraction of part of the output and suitable signal processing. An experimental program has been conducted to evaluate the usefulness of this technique in the cases of simple, cantilever-beam and free-free plate structures as well as in that of a complex mechanical system. On the basis of the transfer functions thus recovered, it was possible to evaluate the shifts in the resonance frequencies of a structure due to the presence of defects.

A CAI System for Visually Impaired Children to Improve Abilities of Orientation and Mobility

NASA Astrophysics Data System (ADS)

Yoneda, Takahiro; Kudo, Hiroaki; Minagawa, Hiroki; Ohnishi, Noboru; Matsubara, Shizuya

Some visually impaired children have difficulty in simple locomotion, and need orientation and mobility training. We developed a computer assisted instruction system which assists this training. A user realizes a task given by a tactile map and synthesized speech. The user walks around a room according to the task. The system gives the gap of walk path from its target path via both auditory and tactile feedback after the end of a task. Then the user can understand how well the user walked. We describe the detail of the proposed system and task, and the experimental result with three visually impaired children.

Multilevel recording of complex amplitude data pages in a holographic data storage system using digital holography.

PubMed

Nobukawa, Teruyoshi; Nomura, Takanori

2016-09-05

A holographic data storage system using digital holography is proposed to record and retrieve multilevel complex amplitude data pages. Digital holographic techniques are capable of modulating and detecting complex amplitude distribution using current electronic devices. These techniques allow the development of a simple, compact, and stable holographic storage system that mainly consists of a single phase-only spatial light modulator and an image sensor. As a proof-of-principle experiment, complex amplitude data pages with binary amplitude and four-level phase are recorded and retrieved. Experimental results show the feasibility of the proposed holographic data storage system.

A study on the dynamic interfacial tension of acidic crude oil/alkali (alkali-polymer) systems--

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

Huang, Y.; Yang, P.; Qin, T.

1989-01-01

This paper describes the investigation of dynamic interfacial tension (DIFT) between the acidic Liao-He crude oil and two types of brine: a simple alkali system and a combined alkali-polymer system. It was found that interfacial tension (IFT) changed markedly with time and that the history of DIFT depended upon the concentration of alkali in the brine. The experimental results also showed that the IFT dropped dramatically as soon as the fresh oil contacted brine causing spontaneous emulsification to occur. The steady-state value of DIFT {gamma} st can be lower with the combined alkali-polymer system than with the simple alkali system.more » The results indicate that biopolymer is more effective than partially hydrolyzed polyacrylamide (PHPAM) for lowering {gamma} st and that Na{sub 2}Co{sub 1} causes a lower {gamma} st than NaOH in the combined alkali-polymer system. Optimized formulations containing Na{sub 2}CO{sub 3} added biopolymer can reduce {gamma} st by two orders of magnitude, and PHPAM can reduce {gamma} st by one order of magnitude. The interaction between alkali and polymer in the combined alkali-polymer system is discussed.« less

The Effects of Direct Oxygen Supply During Static Cold Preservation of Rat Livers: An Experimental Study.

PubMed

Zumrutdal, Emin; Karateke, Faruk; Eser, Pınar Eylem; Turan, Umit; Ozyazici, Sefa; Sozutek, Alper; Gulkaya, Mustafa; Kunt, Mevlut

2016-12-01

We aimed to determine the biochemical and histopathologic effects of direct oxygen supply to the preservation fluid of static cold storage system with a simple method on rat livers. Sixteen rats were randomly divided into 2 groups: the control group, which contained Ringer's lactate as preservation fluid; and the oxygen group, which contained oxygen and Ringer's lactate for preservation. Each liver was placed in a bag containing 50 mL Ringer's lactate and placed in ice-filled storage containers. One hundred percent oxygen supplies were given via a simple, inexpensive system created in our laboratory, to the livers in oxygen group. We obtained samples for histopathologic evaluation in the 12th hour. In addition, 3 mL of preservation fluid was subjected to biochemical analysis at 0, sixth, and twelfth hours. Aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and pH levels were measured from the preservation fluid. In oxygen-supplemented group, the acceleration speed of increase in alanine aminotransferase and lactate dehydrogenase levels at sixth hour and lactate dehydrogenase, alanine aminotransferase, and lactate dehydrogenase levels at 12th hour were statistically significantly reduced. In histopathologic examination, all parameters except ballooning were statistically significantly better in the oxygen-supplemented group. This simple system for oxygenation of liver tissues during static cold storage was shown to be effective with good results in biochemical and histopathologic assessments. Because this is a simple, inexpensive, and easily available method, larger studies are warranted to evaluate its effects (especially in humans).

A Simulation Study on the Performance of the Simple Difference and Covariance-Adjusted Scores in Randomized Experimental Designs

ERIC Educational Resources Information Center

Petscher, Yaacov; Schatschneider, Christopher

2011-01-01

Research by Huck and McLean (1975) demonstrated that the covariance-adjusted score is more powerful than the simple difference score, yet recent reviews indicate researchers are equally likely to use either score type in two-wave randomized experimental designs. A Monte Carlo simulation was conducted to examine the conditions under which the…

Control of the collapse distance in atmospheric propagation

NASA Astrophysics Data System (ADS)

Fibich, Gadi; Sivan, Yonatan; Ehrlich, Yosi; Louzon, Einat; Fraenkel, Moshe; Eisenmann, Shmuel; Katzir, Yiftach; Zigler, Arie

2006-06-01

We show experimentally for ultrashort laser pulses propagating in air, that the collapse/filamentation distance of intense laser pulses in the atmosphere can be extended and controlled with a simple double-lens setup. We derive a simple formula for the filamentation distance, and confirm its agreement with the experimental results. We also observe that delaying the onset of filamentation increases the filament length.

A low-cost, computer-controlled robotic flower system for behavioral experiments.

PubMed

Kuusela, Erno; Lämsä, Juho

2016-04-01

Human observations during behavioral studies are expensive, time-consuming, and error prone. For this reason, automatization of experiments is highly desirable, as it reduces the risk of human errors and workload. The robotic system we developed is simple and cheap to build and handles feeding and data collection automatically. The system was built using mostly off-the-shelf components and has a novel feeding mechanism that uses servos to perform refill operations. We used the robotic system in two separate behavioral studies with bumblebees (Bombus terrestris): The system was used both for training of the bees and for the experimental data collection. The robotic system was reliable, with no flight in our studies failing due to a technical malfunction. The data recorded were easy to apply for further analysis. The software and the hardware design are open source. The development of cheap open-source prototyping platforms during the recent years has opened up many possibilities in designing of experiments. Automatization not only reduces workload, but also potentially allows experimental designs never done before, such as dynamic experiments, where the system responds to, for example, learning of the animal. We present a complete system with hardware and software, and it can be used as such in various experiments requiring feeders and collection of visitation data. Use of the system is not limited to any particular experimental setup or even species.

Histological analysis of the repair of dural lesions with silicone mesh in rats subjected to experimental lesions

PubMed Central

da Rosa, Fernando William Figueiredo; Pohl, Pedro Henrique Isoldi; Mader, Ana Maria Amaral Antônio; de Paiva, Carla Peluso; dos Santos, Aline Amaro; Bianco, Bianca; Rodrigues, Luciano Miller Reis

2015-01-01

ABSTRACT Objective To evaluate inflammatory reaction, fibrosis and neovascularization in dural repairs in Wistar rats using four techniques: simple suture, bovine collagen membrane, silicon mesh and silicon mesh with suture. Methods Thirty Wistar rats were randomized in five groups: the first was the control group, submitted to dural tear only. The others underwent durotomy and simple suture, bovine collagen membrane, silicon mesh and silicon mesh with suture. Animals were euthanized and the spine was submitted to histological evaluation with a score system (ranging from zero to 3) for inflammation, neovascularization and fibrosis. Results Fibrosis was significantly different between simple suture and silicon mesh (p=0.005) and between simple suture and mesh with suture (p=0.015), showing that fibrosis is more intense when a foreign body is used in the repair. Bovine membrane was significantly different from mesh plus suture (p=0.011) regarding vascularization. Inflammation was significantly different between simple suture and bovine collagen membrane. Conclusion Silicon mesh, compared to other commercial products available, is a possible alternative for dural repair. More studies are necessary to confirm these findings. PMID:26761555

Generation of flower high-order Poincaré sphere laser beams from a spatial light modulator

NASA Astrophysics Data System (ADS)

Lu, T. H.; Huang, T. D.; Wang, J. G.; Wang, L. W.; Alfano, R. R.

2016-12-01

We propose and experimentally demonstrate a new complex laser beam with inhomogeneous polarization distributions mapping onto high-order Poincaré spheres (HOPSs). The complex laser mode is achieved by superposition of Laguerre-Gaussian modes and manifests exotic flower-like localization on intensity and phase profiles. A simple optical system is used to generate a polarization-variant distribution on the complex laser mode by superposition of orthogonal circular polarizations with opposite topological charges. Numerical analyses of the polarization distribution are consistent with the experimental results. The novel flower HOPS beams can act as a new light source for photonic applications.

Nonlinear dispersive waves in repulsive lattices

NASA Astrophysics Data System (ADS)

Mehrem, A.; Jiménez, N.; Salmerón-Contreras, L. J.; García-Andrés, X.; García-Raffi, L. M.; Picó, R.; Sánchez-Morcillo, V. J.

2017-07-01

The propagation of nonlinear waves in a lattice of repelling particles is studied theoretically and experimentally. A simple experimental setup is proposed, consisting of an array of coupled magnetic dipoles. By driving harmonically the lattice at one boundary, we excite propagating waves and demonstrate different regimes of mode conversion into higher harmonics, strongly influenced by dispersion and discreteness. The phenomenon of acoustic dilatation of the chain is also predicted and discussed. The results are compared with the theoretical predictions of the α -Fermi-Pasta-Ulam equation, describing a chain of masses connected by nonlinear quadratic springs and numerical simulations. The results can be extrapolated to other systems described by this equation.

High-pressure-assisted X-ray-induced damage as a new route for materials synthesis

DOE PAGES

Evlyukhin, Egor; Kim, Eunja; Goldberger, David; ...

2018-01-01

X-ray radiation induced damage has been known for decades and has largely been viewed as a tremendous nuisance; e.g., most X-ray-related studies of organic and inorganic materials suffer X-ray damage to varying degrees. Although, recent theoretical and experimental investigation of the response of simple chemical systems to X-rays offered better understanding of the mechanistic details of X-ray induced damage, the question about useful applicability of this technique is still unclear. Furthermore we experimentally demonstrate that by tuning pressure and X-ray energy, the radiation induced damage can be controlled and used for synthesis of novel materials.

Effects of crowders on the equilibrium and kinetic properties of protein aggregation

NASA Astrophysics Data System (ADS)

Bridstrup, John; Yuan, Jian-Min

2016-08-01

The equilibrium and kinetic properties of protein aggregation systems in the presence of crowders are investigated using simple, illuminating models based on mass-action laws. Our model yields analytic results for equilibrium properties of protein aggregates, which fit experimental data of actin and ApoC-II with crowders reasonably well. When the effects of crowders on rate constants are considered, our kinetic model is in good agreement with experimental results for actin with dextran as the crowder. Furthermore, the model shows that as crowder volume fraction increases, the length distribution of fibrils becomes narrower and shifts to shorter values due to volume exclusion.

High-speed holocinematographic velocimeter for studying turbulent flow control physics

NASA Technical Reports Server (NTRS)

Weinstein, L. M.; Beeler, G. B.; Lindemann, A. M.

1985-01-01

Use of a dual view, high speed, holographic movie technique is examined for studying turbulent flow control physics. This approach, which eliminates some of the limitations of previous holographic techniques, is termed a holocinematographic velocimeter (HCV). The data from this system can be used to check theoretical turbulence modeling and numerical simulations, visualize and measure coherent structures in 'non-simple' turbulent flows, and examine the mechanisms operative in various turbulent control/drag reduction concepts. This system shows promise for giving the most complete experimental characterization of turbulent flows yet available.

Sequence design and software environment for real-time navigation of a wireless ferromagnetic device using MRI system and single echo 3D tracking.

PubMed

Chanu, A; Aboussouan, E; Tamaz, S; Martel, S

2006-01-01

Software architecture for the navigation of a ferromagnetic untethered device in a 1D and 2D phantom environment is briefly described. Navigation is achieved using the real-time capabilities of a Siemens 1.5 T Avanto MRI system coupled with a dedicated software environment and a specially developed 3D tracking pulse sequence. Real-time control of the magnetic core is executed through the implementation of a simple PID controller. 1D and 2D experimental results are presented.

Microcomputer technology applications: Charger and regulator software for a breadboard programmable power processor

NASA Technical Reports Server (NTRS)

Green, D. M.

1978-01-01

Software programs are described, one which implements a voltage regulation function, and one which implements a charger function with peak-power tracking of its input. The software, written in modular fashion, is intended as a vehicle for further experimentation with the P-3 system. A control teleprinter allows an operator to make parameter modifications to the control algorithm during experiments. The programs require 3K ROM and 2K ram each. User manuals for each system are included as well as a third program for simple I/O control.

Dynamic characteristics of a vibrating beam with periodic variation in bending stiffness

NASA Technical Reports Server (NTRS)

Townsend, John S.

1987-01-01

A detailed dynamic analysis is performed of a vibrating beam with bending stiffness periodic in the spatial coordinate. The effects of system parameters on beam response are explored with a perturbation expansion technique. It is found that periodic stiffness acts to modulate the modal displacements from the characteristic shape of a simple sine wave. The results are verified by a finite element solution and through experimental testing.

Investigations and Tests in the Towing Basin at Guidonia

NASA Technical Reports Server (NTRS)

Cremona, C

1939-01-01

The experimental methods at the Guidonia towing basin are discussed including specifications. Some of the components examined are the bridge towing carriage, side towing carriage, catapult installation, and dynamometer systems. Tests were performed on hulls and floats, as well as motor boats and torpedo shaped bodies. Theoretical investigations were also performed to determine pressure distributions on geometrically simple bodies, propagation of small wave motions, and planing and submerged surfaces.

Review of Surface Properties of Thermal Protection Materials for the Design of IXV Thermal Protection System

NASA Astrophysics Data System (ADS)

Thoemel, J.; Cosson, E.; Chazot, O.

2009-01-01

In the framework of the creation of an aerothermodynamic database for the design the Intermediate Experimental Vehicle, surface properties of heat shield materials that represent the boundary conditions are reviewed. Catalytic and radiative characteristics available in the literature are critically analyzed and summarized. It turns out that large uncertainties on the parameters exist. Finally, simple and conservative values are proposed.

SOAR: An Architecture for General Intelligence

DTIC Science & Technology

1987-12-01

these tasks, and (3) learn about all aspects of the tasks and its performance on them. Soar has existed since mid 1982 as an experimental software system...intelligence. Soar’s behavior has already been studied over a range of tasks and methods (Figure 1), which sample its intended range, though...in multiple small tasks: Generate and test, AND/OR search, hill climbing ( simple and steepest-ascent), means-ends analysis, operator subgoaling

Extraction of In-Medium Nucleon-Nucleon Amplitude From Experiment

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

1998-01-01

The in-medium nucleon-nucleon amplitudes are extracted from the available proton-nucleus total reaction cross sections data. The retrieval of the information from the experiment makes the estimate of reaction cross sections very reliable. Simple expressions are given for the in-medium nucleon-nucleon amplitudes for any system of colliding nuclei as a function of energy. Excellent agreement with experimental observations is demonstrated in the ion-nucleus interactions.

A new fitting law of rovibrationally inelastic rate constants for rapidly rotating molecules

NASA Astrophysics Data System (ADS)

Strekalov, M. L.

2005-04-01

Semiclassical scattering of a particle from a three-dimensional ellipsoid with internal structure is used to model vibration-rotation-translation (VRT) collisional transfer between atoms and diatomic molecules. The result is a very simple analytical expression containing two variable parameters that have a clear physical meaning. Predictions of the model for the Li 2 + Ne system are in reasonably good agreement with experimental results.

A novel method for the accurate evaluation of Poisson's ratio of soft polymer materials.

PubMed

Lee, Jae-Hoon; Lee, Sang-Soo; Chang, Jun-Dong; Thompson, Mark S; Kang, Dong-Joong; Park, Sungchan; Park, Seonghun

2013-01-01

A new method with a simple algorithm was developed to accurately measure Poisson's ratio of soft materials such as polyvinyl alcohol hydrogel (PVA-H) with a custom experimental apparatus consisting of a tension device, a micro X-Y stage, an optical microscope, and a charge-coupled device camera. In the proposed method, the initial positions of the four vertices of an arbitrarily selected quadrilateral from the sample surface were first measured to generate a 2D 1st-order 4-node quadrilateral element for finite element numerical analysis. Next, minimum and maximum principal strains were calculated from differences between the initial and deformed shapes of the quadrilateral under tension. Finally, Poisson's ratio of PVA-H was determined by the ratio of minimum principal strain to maximum principal strain. This novel method has an advantage in the accurate evaluation of Poisson's ratio despite misalignment between specimens and experimental devices. In this study, Poisson's ratio of PVA-H was 0.44 ± 0.025 (n = 6) for 2.6-47.0% elongations with a tendency to decrease with increasing elongation. The current evaluation method of Poisson's ratio with a simple measurement system can be employed to a real-time automated vision-tracking system which is used to accurately evaluate the material properties of various soft materials.

PREFACE: Ionic fluids Ionic fluids

NASA Astrophysics Data System (ADS)

Levin, Yan; Kornyshev, Alexei; Barbosa, Marcia C.

2009-10-01

In spite of its apparent simplicity Coulomb law, when applied to many body systems, leads to an amazingly rich mathematical structure. The simple idea that two similarly charged objects always repel, is not necessarily true in a colloidal suspension or a dusty plasma. Neither can one simply predict the direction of the electrophoretic motion of a polyion from only knowing its chemical charge. Strong Coulomb correlations in ionic fluids result in instabilities very similar to the gas--liquid phase separation observed in atomic fluids. It is fair to say that bulk behavior of simple aqueous monovalent electrolytes is now very well understood. Unfortunately this is not the case for multivalent electrolytes or molten salts. In these systems cation-anion association leads to strong non-linear effects which manifest themselves in formations of tightly bound ionic clusters. In spite of the tremendous effort invested over the years, our understanding of these systems remains qualitative. In this special issue we have collected articles from some of the biggest experts working on ionic fluids. The papers are both experimental and theoretical. They range from simple electrolytes in the bulk and near interfaces, to polyelectrolytes, colloids, and molten salts. The special issue, covers a wide spectrum of the ongoing research on ionic fluids. All readers should find something of interest here.

Simple and efficient machine learning frameworks for identifying protein-protein interaction relevant articles and experimental methods used to study the interactions.

PubMed

Agarwal, Shashank; Liu, Feifan; Yu, Hong

2011-10-03

Protein-protein interaction (PPI) is an important biomedical phenomenon. Automatically detecting PPI-relevant articles and identifying methods that are used to study PPI are important text mining tasks. In this study, we have explored domain independent features to develop two open source machine learning frameworks. One performs binary classification to determine whether the given article is PPI relevant or not, named "Simple Classifier", and the other one maps the PPI relevant articles with corresponding interaction method nodes in a standardized PSI-MI (Proteomics Standards Initiative-Molecular Interactions) ontology, named "OntoNorm". We evaluated our system in the context of BioCreative challenge competition using the standardized data set. Our systems are amongst the top systems reported by the organizers, attaining 60.8% F1-score for identifying relevant documents, and 52.3% F1-score for mapping articles to interaction method ontology. Our results show that domain-independent machine learning frameworks can perform competitively well at the tasks of detecting PPI relevant articles and identifying the methods that were used to study the interaction in such articles. Simple Classifier is available at http://sourceforge.net/p/simpleclassify/home/ and OntoNorm at http://sourceforge.net/p/ontonorm/home/.

Modelling melting in crustal environments, with links to natural systems in the Nepal Himalayas

NASA Astrophysics Data System (ADS)

Isherwood, C.; Holland, T.; Bickle, M.; Harris, N.

2003-04-01

Melt bodies of broadly granitic character occur frequently in mountain belts such as the Himalayan chain which exposes leucogranitic intrusions along its entire length (e.g. Le Fort, 1975). The genesis and disposition of these bodies have considerable implications for the development of tectonic evolution models for such mountain belts. However, melting processes and melt migration behaviour are influenced by many factors (Hess, 1995; Wolf &McMillan, 1995) which are as yet poorly understood. Recent improvements in internally consistent thermodynamic datasets have allowed the modelling of simple granitic melt systems (Holland &Powell, 2001) at pressures below 10 kbar, of which Himalayan leucogranites provide a good natural example. Model calculations such as these have been extended to include an asymmetrical melt-mixing model based on the Van Laar approach, which uses volumes (or pseudovolumes) for the different end-members in a mixture to control the asymmetry of non-ideal mixing. This asymmetrical formalism has been used in conjunction with several different entropy of mixing assumptions in an attempt to find the closest fit to available experimental data for melting in simple binary and ternary haplogranite systems. The extracted mixing data are extended to more complex systems and allow the construction of phase relations in NKASH necessary to model simple haplogranitic melts involving albite, K-feldspar, quartz, sillimanite and {H}2{O}. The models have been applied to real bulk composition data from Himalayan leucogranites.

Experimental Investigation of the Flow on a Simple Frigate Shape (SFS)

PubMed Central

Mora, Rafael Bardera

2014-01-01

Helicopters operations on board ships require special procedures introducing additional limitations known as ship helicopter operational limitations (SHOLs) which are a priority for all navies. This paper presents the main results obtained from the experimental investigation of a simple frigate shape (SFS) which is a typical case of study in experimental and computational aerodynamics. The results obtained in this investigation are used to make an assessment of the flow predicted by the SFS geometry in comparison with experimental data obtained testing a ship model (reduced scale) in the wind tunnel and on board (full scale) measurements performed on a real frigate type ship geometry. PMID:24523646

Models of cooperative dynamics from biomolecules to magnets

NASA Astrophysics Data System (ADS)

Mobley, David Lowell

This work details application of computer models to several biological systems (prion diseases and Alzheimer's disease) and a magnetic system. These share some common themes, which are discussed. Here, simple lattice-based models are applied to aggregation of misfolded protein in prion diseases like Mad Cow disease. These can explain key features of the diseases. The modeling is based on aggregation being essential in establishing the time-course of infectivity. Growth of initial aggregates is assumed to dominate the experimentally observed lag phase. Subsequent fission, regrowth, and fission set apart the exponential doubling phase in disease progression. We explore several possible modes of growth for 2-D aggregates and suggest the model providing the best explanation for the experimental data. We develop testable predictions from this model. Like prion disease, Alzheimer's disease (AD) is an amyloid disease characterized by large aggregates in the brain. However, evidence increasingly points away from these as the toxic agent and towards oligomers of the Abeta peptide. We explore one possible toxicity mechanism---insertion of Abeta into cell membranes and formation of harmful ion channels. We find that mutations in this peptide which cause familial Alzheimer's disease (FAD) also affect the insertion of this peptide into membranes in a fairly consistent way, suggesting that this toxicity mechanism may be relevant biologically. We find a particular inserted configuration which may be especially harmful and develop testable predictions to verify whether or not this is the case. Nucleation is an essential feature of our models for prion disease, in that it protects normal, healthy individuals from getting prion disease. Nucleation is important in many other areas, and we modify our lattice-based nucleation model to apply to a hysteretic magnetic system where nucleation has been suggested to be important. From a simple model, we find qualitative agreement with experiment, and make testable experimental predictions concerning time-dependence and temperature-dependence of the major hysteresis loop and reversal curves which have been experimentally verified. We argue why this model may be suitable for systems like these and explain implications for Ising-like models. We suggest implications for future modeling work. Finally, we present suggestions for future work in all three areas.

A Virtual Blind Cane Using a Line Laser-Based Vision System and an Inertial Measurement Unit

PubMed Central

Dang, Quoc Khanh; Chee, Youngjoon; Pham, Duy Duong; Suh, Young Soo

2016-01-01

A virtual blind cane system for indoor application, including a camera, a line laser and an inertial measurement unit (IMU), is proposed in this paper. Working as a blind cane, the proposed system helps a blind person find the type of obstacle and the distance to it. The distance from the user to the obstacle is estimated by extracting the laser coordinate points on the obstacle, as well as tracking the system pointing angle. The paper provides a simple method to classify the obstacle’s type by analyzing the laser intersection histogram. Real experimental results are presented to show the validity and accuracy of the proposed system. PMID:26771618

Automation effects in a stereotypical multiloop manual control system. [for aircraft

NASA Technical Reports Server (NTRS)

Hess, R. A.; Mcnally, B. D.

1984-01-01

The increasing reliance of state-of-the art, high performance aircraft on high authority stability and command augmentation systems, in order to obtain satisfactory performance and handling qualities, has made critical the achievement of a better understanding of human capabilities, limitations, and preferences during interactions with complex dynamic systems that involve task allocation between man and machine. An analytical and experimental study has been undertaken to investigate human interaction with a simple, multiloop dynamic system in which human activity was systematically varied by changing the levels of automation. Task definition has led to a control loop structure which parallels that for any multiloop manual control system, and may therefore be considered a stereotype.

Flight evaluation of a simple total energy-rate system with potential wind-shear application

NASA Technical Reports Server (NTRS)

Ostroff, A. J.; Hueschen, R. M.; Hellbaum, R. F.; Creedon, J. F.

1981-01-01

Wind shears can create havoc during aircraft terminal area operations and have been cited as the primary cause of several major aircraft accidents. A simple sensor, potentially having application to the wind-shear problem, was developed to rapidly measure aircraft total energy relative to the air mass. Combining this sensor with either a variometer or a rate-of-climb indicator provides a total energy-rate system which was successfully applied in soaring flight. The measured rate of change of aircraft energy can potentially be used on display/control systems of powered aircraft to reduce glide-slope deviations caused by wind shear. The experimental flight configuration and evaluations of the energy-rate system are described. Two mathematical models are developed: the first describes operation of the energy probe in a linear design region and the second model is for the nonlinear region. The calculated total rate is compared with measured signals for many different flight tests. Time history plots show the tow curves to be almost the same for the linear operating region and very close for the nonlinear region.

Title: Experimental and analytical study of frictional anisotropy of nanotubes

NASA Astrophysics Data System (ADS)

Riedo, Elisa; Gao, Yang; Li, Tai-De; Chiu, Hsiang-Chih; Kim, Suenne; Klinke, Christian; Tosatti, Erio

The frictional properties of Carbon and Boron Nitride nanotubes (NTs) are very important in a variety of applications, including composite materials, carbon fibers, and micro/nano-electromechanical systems. Atomic force microscopy (AFM) is a powerful tool to investigate with nanoscale resolution the frictional properties of individual NTs. Here, we report on an experimental study of the frictional properties of different types of supported nanotubes by AFM. We also propose a quantitative model to describe and then predict the frictional properties of nanotubes sliding on a substrate along (longitudinal friction) or perpendicular (transverse friction) their axis. This model provides a simple but general analytical relationship that well describes the acquired experimental data. As an example of potential applications, this experimental method combined with the proposed model can guide to design better NTs-ceramic composites, or to self-assemble the nanotubes on a surface in a given direction. M. Lucas et al., Nature Materials 8, 876-881 (2009).

Asymmetric Marcus-Hush theory for voltammetry.

PubMed

Laborda, Eduardo; Henstridge, Martin C; Batchelor-McAuley, Christopher; Compton, Richard G

2013-06-21

The current state-of-the-art in modeling the rate of electron transfer between an electroactive species and an electrode is reviewed. Experimental studies show that neither the ubiquitous Butler-Volmer model nor the more modern symmetric Marcus-Hush model are able to satisfactorily reproduce the experimental voltammetry for both solution-phase and surface-bound redox couples. These experimental deviations indicate the need for revision of the simplifying approximations used in the above models. Within this context, models encompassing asymmetry are considered which include different vibrational and solvation force constants for the electroactive species. The assumption of non-adiabatic electron transfer is also examined. These refinements have provided more satisfactory models of the electron transfer process and they enable us to gain more information about the microscopic characteristics of the system by means of simple electrochemical measurements.

An experimental study on the effect of temperature on piezoelectric sensors for impedance-based structural health monitoring.

PubMed

Baptista, Fabricio G; Budoya, Danilo E; de Almeida, Vinicius A D; Ulson, Jose Alfredo C

2014-01-10

The electromechanical impedance (EMI) technique is considered to be one of the most promising methods for developing structural health monitoring (SHM) systems. This technique is simple to implement and uses small and inexpensive piezoelectric sensors. However, practical problems have hindered its application to real-world structures, and temperature effects have been cited in the literature as critical problems. In this paper, we present an experimental study of the effect of temperature on the electrical impedance of the piezoelectric sensors used in the EMI technique. We used 5H PZT (lead zirconate titanate) ceramic sensors, which are commonly used in the EMI technique. The experimental results showed that the temperature effects were strongly frequency-dependent, which may motivate future research in the SHM field.

Experimental and theoretical investigation of the stability of stepwise pH gradients in continuous flow electrophoresis

NASA Technical Reports Server (NTRS)

Kuhn, Reinhard; Wagner, Horst; Mosher, Richard A.; Thormann, Wolfgang

1987-01-01

Isoelectric focusing in the continuous flow mode can be more quickly and economically performed by admitting a stepwise pH gradient composed of simple buffers instead of uniform mixtures of synthetic carrier ampholytes. The time-consuming formation of the pH gradient by the electric field is thereby omitted. The stability of a three-step system with arginine - morpholinoethanesulfonic acid/glycylglycine - aspartic acid is analyzed theoretically by one-dimensional computer simulation as well as experimentally at various flow rates in a continuous flow apparatus. Excellent agreement between experimental and theoretical data was obtained. This metastable configuration was found to be suitable for focusing of proteins under continuous flow conditions. The influence of various combinations of electrolytes and membranes between electrophoresis chamber and electrode compartments is also discussed.

Experimental evidence for an effect of early-diagenetic interaction between labile and refractory marine sedimentary organic matter on nitrogen dynamics

NASA Astrophysics Data System (ADS)

Turnewitsch, Robert; Domeyer, Bettina; Graf, Gerhard

2007-05-01

In most natural sedimentary systems labile and refractory organic material (OM) occur concomitantly. Little, however, is known on how different kinds of OM interact and how such interactions affect early diagenesis in sediments. In a simple sediment experiment, we investigated how interactions of OM substrates of different degradability affect benthic nitrogen (N) dynamics. Temporal evolution of a set of selected biogeochemical parameters was monitored in sandy sediment over 116 days in three experimental set-ups spiked with labile OM (tissue of Mytilus edulis), refractory OM (mostly aged Zostera marina and macroalgae), and a 1:1 mixture of labile and refractory OM. The initial amounts of particulate organic carbon (POC) were identical in the three set-ups. To check for non-linear interactions between labile and refractory OM, the evolution of the mixture system was compared with the evolution of the simple sum of the labile and refractory systems, divided by two. The sum system is the experimental control where labile and refractory OM are virtually combined but not allowed to interact. During the first 30 days there was evidence for net dissolved-inorganic-nitrogen (DIN) production followed by net DIN consumption. (Here 'DIN' is the sum of ammonium, nitrite and nitrate.) After ˜ 30 days a quasi steady state was reached. Non-linear interactions between the two types of OM were reflected by three main differences between the early-diagenetic evolutions of nitrogen dynamics of the mixture and sum (control) systems: (1) In the mixture system the phases of net DIN production and consumption commenced more rapidly and were more intense. (2) The mixture system was shifted towards a more oxidised state of DIN products [as indicated by increased (nitrite + nitrate)/(ammonium) ratios]. (3) There was some evidence that more OM, POC and particulate nitrogen were preserved in the mixture system. That is, in the mixture system more particulate OM was preserved while a higher proportion of the decomposed particulate N was converted into inorganic N. It can be concluded that during the first days and weeks of early diagenesis the magnitude and composition of the flux of decompositional dissolved N-compounds from sediments into the overlying water was influenced by non-linear interactions of OM substrates of different degradability. Given these experimental results it is likely that the relative spatial distributions of OM of differing degradability in sediments control the magnitude and composition of the return flux of dissolved N-bearing compounds from sediments into the overlying water column.

[A simple testing installation for the production of aerosols with constant bacteria-contaminated concentrations].

PubMed

Herbst, M; Lehmhus, H; Oldenburg, B; Orlowski, C; Ohgke, H

1983-04-01

A simple experimental set for the production and investigation of bacterially contaminated solid-state aerosols with constant concentration is described. The experimental set consists mainly of a fluidized bed-particle generator within a modified chamber for formaldehyde desinfection. The special conditions for the production of a defined concentration of particles and microorganisms are to be found out empirically. In a first application aerosol-sizing of an Andersen sampler is investigated. The findings of Andersen (1) are confirmed with respect to our experimental conditions.

A Simple Laboratory Class Using a "Pseudomonas aeruginosa" Auxotroph to Illustrate UV-Mutagenic Killing, DNA Photorepair and Mutagenic DNA Repair

ERIC Educational Resources Information Center

Sobrero, Patricio; Valverde, Claudio

2013-01-01

A simple and cheap laboratory class is proposed to illustrate the lethal effect of UV radiation on bacteria and the operation of different DNA repair mechanisms. The class is divided into two sessions, an initial 3-hour experimental session and a second 2-hour analytical session. The experimental session involves two separate experiments: one…

A simple model of proton damage in GaAs solar cells

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Walker, G. H.; Outlaw, R. A.

1982-01-01

A simple proton damage model for GaAs solar cells is derived and compared to experimental values of change in short circuit currents. The recombination cross section associated with the defects was determined from the experimental comparison to be approximately 1.2 x 10 to the -13th power sq cm in fair agreement with values determined from the deep level transient spectroscopy technique.

An efficient planar accordion-shaped micromixer: from biochemical mixing to biological application

PubMed Central

Cosentino, Armando; Madadi, Hojjat; Vergara, Paola; Vecchione, Raffaele; Causa, Filippo; Netti, Paolo Antonio

2015-01-01

Micromixers are the key component that allow lab-on-a-chip and micro total analysis systems to reach the correct level of mixing for any given process. This paper proposes a novel, simple, passive micromixer design characterized by a planar accordion-shape geometry. The geometrical characteristics of the presented design were analyzed numerically in the range of 0.01 < Re < 100 based on the micromixer performance. The performance of the most efficient design was experimentally investigated by means of fluorescence microscopy for a range of low diffusion coefficients, 10−12 < D < 10−11 m2/s. The micromixer structure was fabricated in a simple single-step process using maskless lithography and soft lithography. The experimental results showed a very good agreement with the predicted numerical results. This micromixer design including a single serpentine unit (1-SERP) displayed an efficiency higher than 90% (mixing length = 6.4 mm) creating a pressure drop of about 500 Pa at Re = 0.1 and 60 kPa at Re = 10. A mixing efficiency of almost 100% was readily reached when three serpentine units were included (3-SERP). Finally, the potential diagnostic value of the presented microdevice was validated experimentally for Red Blood Cell (RBC) lysis. PMID:26658848

An efficient planar accordion-shaped micromixer: from biochemical mixing to biological application

NASA Astrophysics Data System (ADS)

Cosentino, Armando; Madadi, Hojjat; Vergara, Paola; Vecchione, Raffaele; Causa, Filippo; Netti, Paolo Antonio

2015-12-01

Micromixers are the key component that allow lab-on-a-chip and micro total analysis systems to reach the correct level of mixing for any given process. This paper proposes a novel, simple, passive micromixer design characterized by a planar accordion-shape geometry. The geometrical characteristics of the presented design were analyzed numerically in the range of 0.01 < Re < 100 based on the micromixer performance. The performance of the most efficient design was experimentally investigated by means of fluorescence microscopy for a range of low diffusion coefficients, 10-12 < D < 10-11 m2/s. The micromixer structure was fabricated in a simple single-step process using maskless lithography and soft lithography. The experimental results showed a very good agreement with the predicted numerical results. This micromixer design including a single serpentine unit (1-SERP) displayed an efficiency higher than 90% (mixing length = 6.4 mm) creating a pressure drop of about 500 Pa at Re = 0.1 and 60 kPa at Re = 10. A mixing efficiency of almost 100% was readily reached when three serpentine units were included (3-SERP). Finally, the potential diagnostic value of the presented microdevice was validated experimentally for Red Blood Cell (RBC) lysis.

An efficient planar accordion-shaped micromixer: from biochemical mixing to biological application.

PubMed

Cosentino, Armando; Madadi, Hojjat; Vergara, Paola; Vecchione, Raffaele; Causa, Filippo; Netti, Paolo Antonio

2015-12-14

Micromixers are the key component that allow lab-on-a-chip and micro total analysis systems to reach the correct level of mixing for any given process. This paper proposes a novel, simple, passive micromixer design characterized by a planar accordion-shape geometry. The geometrical characteristics of the presented design were analyzed numerically in the range of 0.01 < Re < 100 based on the micromixer performance. The performance of the most efficient design was experimentally investigated by means of fluorescence microscopy for a range of low diffusion coefficients, 10(-12) < D < 10(-11) m(2)/s. The micromixer structure was fabricated in a simple single-step process using maskless lithography and soft lithography. The experimental results showed a very good agreement with the predicted numerical results. This micromixer design including a single serpentine unit (1-SERP) displayed an efficiency higher than 90% (mixing length = 6.4 mm) creating a pressure drop of about 500 Pa at Re = 0.1 and 60 kPa at Re = 10. A mixing efficiency of almost 100% was readily reached when three serpentine units were included (3-SERP). Finally, the potential diagnostic value of the presented microdevice was validated experimentally for Red Blood Cell (RBC) lysis.

Refined Dummy Atom Model of Mg(2+) by Simple Parameter Screening Strategy with Revised Experimental Solvation Free Energy.

PubMed

Jiang, Yang; Zhang, Haiyang; Feng, Wei; Tan, Tianwei

2015-12-28

Metal ions play an important role in the catalysis of metalloenzymes. To investigate metalloenzymes via molecular modeling, a set of accurate force field parameters for metal ions is highly imperative. To extend its application range and improve the performance, the dummy atom model of metal ions was refined through a simple parameter screening strategy using the Mg(2+) ion as an example. Using the AMBER ff03 force field with the TIP3P model, the refined model accurately reproduced the experimental geometric and thermodynamic properties of Mg(2+). Compared with point charge models and previous dummy atom models, the refined dummy atom model yields an enhanced performance for producing reliable ATP/GTP-Mg(2+)-protein conformations in three metalloenzyme systems with single or double metal centers. Similar to other unbounded models, the refined model failed to reproduce the Mg-Mg distance and favored a monodentate binding of carboxylate groups, and these drawbacks needed to be considered with care. The outperformance of the refined model is mainly attributed to the use of a revised (more accurate) experimental solvation free energy and a suitable free energy correction protocol. This work provides a parameter screening strategy that can be readily applied to refine the dummy atom models for metal ions.

Detection of Suspicious Persons using Internet Camera

NASA Astrophysics Data System (ADS)

Terada, Kenji; Kamogashira, Daisuke

Recently, many brutal crimes have shocked us. Therefore, the importance of security and self-defense have increased more and more. It is necessary to develop an automatic method of detecting suspicious persons. In this paper, we propose a method of detecting suspicious persons using the internet camera. An image sequence is obtained by the internet camera. By using these images, the recognition of suspicious persons is carried out. Our method classifies the condition of the target person into 3 postures: walking, staying and sitting. The system employs the subspace method which uses three features: the value of movement, the number of looking around restlessly, and the rate of stopping and going. Some experimental results using a simple experimental system are also reported, which indicate effectiveness of the proposed method. In most scenes, the suspicious persons are able to be detected by the proposed method.

Comment on ``(Au-Ag)144(SR)60 alloy nanomolecules'' by C. Kumara and A. Dass, Nanoscale, 2011, 3, 3064

NASA Astrophysics Data System (ADS)

Barcaro, Giovanni; Sementa, Luca; Fortunelli, Alessandro; Stener, Mauro

2015-04-01

A recent paper in this journal reported the synthesis and characterization via electrospray ionization mass spectroscopy and UV-vis spectroscopy of (Au-Ag)144(SR)60 alloy nanomolecules with different compositions, ranging from 1 : 0 to 1 : 0.75 Au : Ag ratios. The UV-vis spectra of such systems were found to exhibit absorption peaks at 310 nm, 425 nm and 560 nm, interpreted as reminiscent of the silver surface plasmon resonance band due to simple atomic replacement of Au by Ag atoms in a fixed structural framework. On the basis of a comparison of experimentally observed and theoretically simulated optical absorption spectra, we conclude that the experimental situation must be more complicated, and that further work is needed to achieve atomistic insight into these fascinating systems.

Preliminary Analysis of a Water Shield for a Surface Power Reactor

NASA Technical Reports Server (NTRS)

Pearson, J. Boise

2006-01-01

A water based shielding system is being investigated for use on initial lunar surface power systems. The use of water may lower overall cost (as compared to development cost for other materials) and simplify operations in the setup and handling. The thermal hydraulic performance of the shield is of significant interest. The mechanism for transferring heat through the shield is natural convection. A simple 1-D thermal model indicates the necessity of natural convection to maintain acceptable temperatures and pressures in the water shield. CFD analysis is done to quantify the natural convection in the shield, and predicts sufficient natural convection to transfer heat through the shield with small temperature gradients. A test program will he designed to experimentally verify the thermal hydraulic performance of the shield, and to anchor the CFD models to experimental results.

Combined Theoretical and Experimental Study of Refractive Indices of Water-Acetonitrile-Salt Systems.

PubMed

An, Ni; Zhuang, Bilin; Li, Minglun; Lu, Yuyuan; Wang, Zhen-Gang

2015-08-20

We propose a simple theoretical formula for describing the refractive indices in binary liquid mixtures containing salt ions. Our theory is based on the Clausius-Mossotti equation; it gives the refractive index of the mixture in terms of the refractive indices of the pure liquids and the polarizability of the ionic species, by properly accounting for the volume change upon mixing. The theoretical predictions are tested by extensive experimental measurements of the refractive indices for water-acetonitrile-salt systems for several liquid compositions, different salt species, and a range of salt concentrations. Excellent agreement is obtained in all cases, especially at low salt concentrations, with no fitting parameters. A simplified expression of the refractive index for low salt concentration is also given, which can be the theoretical basis for determination of salt concentration using refractive index measurements.

Experience with high performance V/STOL fighter projects at MBB

NASA Technical Reports Server (NTRS)

Aulehla, F.; Kissel, G. K.

1981-01-01

Flight control systems and aerodynamic aspects of experimental V/STOL aircraft are discussed. The VJ 101 C featured tilting engines for increased thrust, reheat for takeoff, simple translation, triangular decentralization of the engines for thrust modulation, and moderate ground effects. Two experimental aircraft were built, with and without reheat, capable of Mach 2 and Mach 1.04, respectively. The mechanical flight control system and tests are outlined, both for hover rig and flight configurations. Ground suction, acoustic and thermal loading, sodium silicate coatings to avoid ground corrosion, and recirculation are considered. Results of the follow-on project to the VJ 101 C, the AVS, which was developed by NASA, are reviewed, and it is noted that trends toward thrust-to-weight ratios exceeding one, in concert with low wing loading, favor the development of V/STOL aircraft.

Experimental study and finite element analysis based on equivalent load method for laser ultrasonic measurement of elastic constants.

PubMed

Zhan, Yu; Liu, Changsheng; Zhang, Fengpeng; Qiu, Zhaoguo

2016-07-01

The laser ultrasonic generation of Rayleigh surface wave and longitudinal wave in an elastic plate is studied by experiment and finite element method. In order to eliminate the measurement error and the time delay of the experimental system, the linear fitting method of experimental data is applied. The finite element analysis software ABAQUS is used to simulate the propagation of Rayleigh surface wave and longitudinal wave caused by laser excitation on a sheet metal sample surface. The equivalent load method is proposed and applied. The pulsed laser is equivalent to the surface load in time and space domain to meet the Gaussian profile. The relationship between the physical parameters of the laser and the load is established by the correction factor. The numerical solution is in good agreement with the experimental result. The simple and effective numerical and experimental methods for laser ultrasonic measurement of the elastic constants are demonstrated. Copyright © 2016. Published by Elsevier B.V.

Evolution equation for quantum coherence

PubMed Central

Hu, Ming-Liang; Fan, Heng

2016-01-01

The estimation of the decoherence process of an open quantum system is of both theoretical significance and experimental appealing. Practically, the decoherence can be easily estimated if the coherence evolution satisfies some simple relations. We introduce a framework for studying evolution equation of coherence. Based on this framework, we prove a simple factorization relation (FR) for the l1 norm of coherence, and identified the sets of quantum channels for which this FR holds. By using this FR, we further determine condition on the transformation matrix of the quantum channel which can support permanently freezing of the l1 norm of coherence. We finally reveal the universality of this FR by showing that it holds for many other related coherence and quantum correlation measures. PMID:27382933

A facile fluorescent "turn-off" method for sensing paraquat based on pyranine-paraquat interaction

NASA Astrophysics Data System (ADS)

Zhao, Zuzhi; Zhang, Fengwei; Zhang, Zipin

2018-06-01

Development of a technically simple yet effective method for paraquat (PQ) detection is of great importance due to its high clinical and environmental relevance. In this study, we developed a pyranine-based fluorescent "turn-off" method for PQ sensing based on pyranine-PQ interaction. We investigated the dependence of analytical performance of this method on the experimental conditions, such as the ion strength, medium pH, and so on. Under the optimized conditions, the method is sensitive and selective, and could be used for PQ detection in real-world sample. This study essentially provides a readily accessible fluorescent system for PQ sensing which is cheap, robust, and technically simple, and it is envisaged to find more interesting clinical and environmental applications.

Easy monitoring of velocity fields in microfluidic devices using spatiotemporal image correlation spectroscopy.

PubMed

Travagliati, Marco; Girardo, Salvatore; Pisignano, Dario; Beltram, Fabio; Cecchini, Marco

2013-09-03

Spatiotemporal image correlation spectroscopy (STICS) is a simple and powerful technique, well established as a tool to probe protein dynamics in cells. Recently, its potential as a tool to map velocity fields in lab-on-a-chip systems was discussed. However, the lack of studies on its performance has prevented its use for microfluidics applications. Here, we systematically and quantitatively explore STICS microvelocimetry in microfluidic devices. We exploit a simple experimental setup, based on a standard bright-field inverted microscope (no fluorescence required) and a high-fps camera, and apply STICS to map liquid flow in polydimethylsiloxane (PDMS) microchannels. Our data demonstrates optimal 2D velocimetry up to 10 mm/s flow and spatial resolution down to 5 μm.

A simple microgravity table for the Orbiter or Space Station

NASA Technical Reports Server (NTRS)

Garriott, O. K.; Debra, D. B.

1985-01-01

Methods of limiting perturbations in microgravity experiments are proposed. An acceleration level below 10 to the -4th m/s-squared is necessary to maintain an undisturbed microgravity environment. Machinery vibrations, crew motion, and the firing of vernier thrusters produce acceleration levels greate than 10 to the -4th m/s-squared. The use of a weak spring system or simple electromagnets to isolate an experimental table from these factors is described. The manners in which crew motion and vernier firing are countered by the springs are examined. The steady acceleration caused by atmospheric drag, gravity gradient force, and steady rotation can be maintained below 10 to the -th m/s-squared; however, the springs can protect the table from these accelerations if required.

Active identification and control of aerodynamic instabilities in axial and centrifugal compressors

NASA Astrophysics Data System (ADS)

Krichene, Assad

In this thesis, it is experimentally shown that dynamic cursors to stall and surge exist in both axial and centrifugal compressors using the experimental axial and centrifugal compressor rigs located in the School of Aerospace Engineering at the Georgia Institute of Technology. Further, it is shown that the dynamic cursors to stall and surge can be identified in real-time and they can be used in a simple control scheme to avoid the occurrence of stall and surge instabilities altogether. For the centrifugal compressor, a previously developed real-time observer is used in order to detect dynamic cursors to surge in real-time. An off-line analysis using the Fast Fourier Transform (FFT) of the open loop experimental data from the centrifugal compressor rig is carried out to establish the influence of compressor speed on the dynamic cursor frequency. The variation of the amplitude of dynamic cursors with compressor operating condition from experimental data is qualitatively compared with simulation results obtained using a generic compression system model subjected to white noise excitation. Using off-line analysis results, a simple control scheme based on fuzzy logic is synthesized for surge avoidance and recovery. The control scheme is implemented in the centrifugal compressor rig using compressor bleed as well as fuel flow to the combustor. Closed loop experimental results are obtained to demonstrate the effectiveness of the controller for both surge avoidance and surge recovery. The existence of stall cursors in an axial compression system is established using the observer scheme from off-line analysis of an existing database of a commercial gas turbine engine. However, the observer scheme is found to be ineffective in detecting stall cursors in the experimental axial compressor rig in the School of Aerospace Engineering at the Georgia Institute of Technology. An alternate scheme based on the amplitude of pressure data content at the blade passage frequency obtained using a pressure sensor located (in the casing) over the blade row is developed and used in the axial compressor rig for stall and surge avoidance and recovery. (Abstract shortened by UMI.)

An automated psychoacoustic testing apparatus for use in cats.

PubMed

Benovitski, Yuri B; Blamey, Peter J; Rathbone, Graeme D; Fallon, James B

2014-03-01

Animal behavioral studies make a significant contribution to hearing research and provide vital information which is not available from human subjects. Animal psychoacoustics is usually extremely time consuming and labor intensive; in addition, animals may become stressed, especially if restraints or negative reinforcers such as electric shocks are used. We present a novel behavioral experimental system that was developed to allow efficient animal training in response to acoustic stimuli. Cats were required to perform a relatively simple task of moving toward and away from the device depending on whether the members of a tone pair were different or the same in frequency (go/no-go task). The experimental setup proved to be effective, with all animals (N = 7) performing at above 90% correct on an easy task. Animals were trained within 2-4 weeks and then generated a total of 150-200 trials per day, distributed within approximately 8 self initiated sessions. Data collected using this system were stable over 1 week and repeatable over long test periods (14 weeks). Measured frequency discrimination thresholds from 3 animals at 3 different reference frequencies were comparable with previously published results. The main advantages of the system are: relatively simple setup; large amounts of data can be generated without the need of researcher supervision; multiple animals can be tested simultaneously without removal from home pens; and no electric shocks or restraints are required. Copyright © 2013 Elsevier B.V. All rights reserved.

A Ulexite-based animation recording system by random reference patterns

NASA Astrophysics Data System (ADS)

Ishii, Yuko; Irisawa, Misako; Takayama, Yoshihisa; Watanabe, Eriko; Kodate, Kashiko

2006-02-01

We propose a simple, compact and high-security holographic optical memory system using Ulexite in order to produce random patterns of reference beam. 100 hologram multiplexing was achieved by multiplexing exposure, rotating Ulexite by 0.2 degrees every time with LiNbO 3 crystal as a recording medium. Moreover, with this system, animation readout images can play for approximately 8 seconds by continuous rotation of Ulexite. As a natural stone, the exactly same Ulexite is very difficult to be found or replicated. Basic experimental results show that Ulexite can be used as a security key for its image-reproducibility and BER calculations.

All-optical animation projection system with rotating fieldstone.

PubMed

Ishii, Yuko; Takayama, Yoshihisa; Kodate, Kashiko

2007-06-11

A simple and compact rewritable holographic memory system using a fieldstone of Ulexite is proposed. The role of the fieldstone is to impose random patterns on the reference beam to record plural images with the random-reference multiplexing scheme. The operations for writing and reading holograms are carried out by simply rotating the fieldstone in one direction. One of the features of this approach is found in a way to generate random patterns without computer drawings. The experimental study confirms that our system enables the smooth readout of the stored images one after another so that the series of reproduced images are projected as an animation.

All-optical animation projection system with rotating fieldstone

NASA Astrophysics Data System (ADS)

Ishii, Yuko; Takayama, Yoshihisa; Kodate, Kashiko

2007-06-01

A simple and compact rewritable holographic memory system using a fieldstone of Ulexite is proposed. The role of the fieldstone is to impose random patterns on the reference beam to record plural images with the random-reference multiplexing scheme. The operations for writing and reading holograms are carried out by simply rotating the fieldstone in one direction. One of the features of this approach is found in a way to generate random patterns without computer drawings. The experimental study confirms that our system enables the smooth readout of the stored images one after another so that the series of reproduced images are projected as an animation.

Research on the thickness control method of workbench oil film based on theoretical model

NASA Astrophysics Data System (ADS)

Pei, Tang; Lin, Lin; Liu, Ge; Yu, Liping; Xu, Zhen; Zhao, Di

2018-06-01

To improve the thickness adjustability of the workbench oil film, we designed a software system to control the thickness of oil film based on the Siemens 840dsl CNC system and set up an experimental platform. A regulation scheme of oil film thickness based on theoretical model is proposed, the accuracy and feasibility of which is proved by experiment results. It's verified that the method mentioned above can meet the demands of workbench oil film thickness control, the experiment is simple and efficient with high control precision. Reliable theory support is supplied for the development of workbench oil film active control system as well.

Experimental OAI-Based Digital Library Systems

NASA Technical Reports Server (NTRS)

Nelson, Michael L. (Editor); Maly, Kurt (Editor); Zubair, Mohammad (Editor); Rusch-Feja, Diann (Editor)

2002-01-01

The objective of Open Archives Initiative (OAI) is to develop a simple, lightweight framework to facilitate the discovery of content in distributed archives (http://www.openarchives.org). The focus of the workshop held at the 5th European Conference on Research and Advanced Technology for Digital Libraries (ECDL 2001) was to bring researchers in the area of digital libraries who are building OAI based systems so as to share their experiences, problems they are facing, and approaches they are taking to address them. The workshop consisted of invited talks from well-established researchers working in building OAI based digital library system along with short paper presentations.

Computational studies of photoluminescence from disordered nanocrystalline systems

NASA Astrophysics Data System (ADS)

John, George

2000-03-01

The size (d) dependence of emission energies from semiconductor nanocrystallites have been shown to follow an effective exponent ( d^-β) determined by the disorder in the system(V.Ranjan, V.A.Singh and G.C.John, Phys. Rev B 58), 1158 (1998). Our earlier calculation was based on a simple quantum confinement model assuming a normal distribution of crystallites. This model is now extended to study the effects of realistic systems with a lognormal distribution in particle size, accounting for carrier hopping and nonradiative transitions. Computer simulations of this model performed using the Microcal Origin software can explain several conflicting experimental results reported in literature.

A Sensing System for Simultaneous Detection of Urine and its Components Using Plastic Optical Fibers

NASA Astrophysics Data System (ADS)

Ejaz, Tahseen; Takemae, Tadashi; Egami, Chikara; Tsuboi, Naoyuki

A sensing system using plastic optical fibers and reagent papers was developed for the detection of urine and abnormal level of its components simultaneously. Among several components of urine the detection of two main components namely, protein and glucose was confirmed experimentally. Three states of the papers namely dry and wet with and without change in color, were taken into consideration. These three states were divided by setting the lower and upper threshold voltages at 2.2 V and 5.5 V, respectively. This system is considered to be simple in construction, easy to operate and cost-efficient.

Modeling of the First Layers in the Fly's Eye

NASA Technical Reports Server (NTRS)

Moya, J. A.; Wilcox, M. J.; Donohoe, G. W.

1997-01-01

Increased autonomy of robots would yield significant advantages in the exploration of space. The shortfalls of computer vision can, however, pose significant limitations on a robot's potential. At the same time, simple insects which are largely hard-wired have effective visual systems. The understanding of insect vision systems thus may lead to improved approaches to visual tasks. A good starting point for the study of a vision system is its eye. In this paper, a model of the sensory portion of the fly's eye is presented. The effectiveness of the model is briefly addressed by a comparison of its performance to experimental data.

Mesoscopic Dynamical Differences from Quantum State Preparation in a Bose-Hubbard Trimer

NASA Astrophysics Data System (ADS)

Olsen, M. K.; Neely, T. W.; Bradley, A. S.

2018-06-01

Conventional wisdom is that quantum effects will tend to disappear as the number of quanta in a system increases, and the evolution of a system will become closer to that described by mean-field classical equations. In this Letter we combine newly developed theoretical and experimental techniques to propose and analyze an experiment using a Bose-Hubbard trimer where the opposite is the case. We find that differences in the preparation of a centrally evacuated trimer can lead to readily observable differences in the subsequent dynamics which increase with system size. Importantly, these differences can be detected by the simple measurements of atomic number.

Expansion of the Center for Network Innovation and Experimentation (CENETIX) Network to a Worldwide Presence

DTIC Science & Technology

2006-09-01

data transform set contains : the security protocol (AH and/or ESP, connection mode (tunnel or transport), encryption information (DES, 3DES, AES...Management Information Base, version 2) objects are variables that contain data about the system. They are defined as part of the Simple Network...Avon Park was configured for access on the concentrator. c. Security Association (SA) • A security association contains all of the information

Coherent direct sequence optical code multiple access encoding-decoding efficiency versus wavelength detuning.

PubMed

Pastor, D; Amaya, W; García-Olcina, R; Sales, S

2007-07-01

We present a simple theoretical model of and the experimental verification for vanishing of the autocorrelation peak due to wavelength detuning on the coding-decoding process of coherent direct sequence optical code multiple access systems based on a superstructured fiber Bragg grating. Moreover, the detuning vanishing effect has been explored to take advantage of this effect and to provide an additional degree of multiplexing and/or optical code tuning.

Computer modeling of pulsed CO2 lasers for lidar applications

NASA Technical Reports Server (NTRS)

Spiers, Gary D.; Smithers, Martin E.; Murty, Rom

1991-01-01

The experimental results will enable a comparison of the numerical code output with experimental data. This will ensure verification of the validity of the code. The measurements were made on a modified commercial CO2 laser. Results are listed as following. (1) The pulse shape and energy dependence on gas pressure were measured. (2) The intrapulse frequency chirp due to plasma and laser induced medium perturbation effects were determined. A simple numerical model showed quantitative agreement with these measurements. The pulse to pulse frequency stability was also determined. (3) The dependence was measured of the laser transverse mode stability on cavity length. A simple analysis of this dependence in terms of changes to the equivalent fresnel number and the cavity magnification was performed. (4) An analysis was made of the discharge pulse shape which enabled the low efficiency of the laser to be explained in terms of poor coupling of the electrical energy into the vibrational levels. And (5) the existing laser resonator code was changed to allow it to run on the Cray XMP under the new operating system.

Optical activity and electronic absorption spectra of some simple nucleosides related to cytidine and uridine: all-valence-shell molecular orbital calculations.

PubMed Central

Miles, D W; Redington, P K; Miles, D L; Eyring, H

1981-01-01

The circular dichroism and electronic absorption of three simple model systems for cytidine and uridine have been measured to 190 nm. The molecular spectral properties (excitation wavelengths, oscillator strengths, rotational strengths, and polarization directions) and electronic transitional patterns were investigated by using wave functions of the entire nucleoside with the goal of establishing the reliability of the theoretical method. The computed electronic absorption quantities were shown to be in satisfactory agreement with experimental data. It was found that the computed optical rotatory strengths of the B2u and E1u electronic transitions and lowest observed n-pi transition are in good agreement with experimental values. Electronic transitions were characterized by their electronic transitional patterns derived from population analysis of the transition density matrix. The theoretical rotational strengths associated with the B2u and E1u transitions stabilize after the use of just a few singly excited configurations in the configuration interaction basis and, hypothetically, are more reliable as indicators of conformation in pyrimidine nucleosides related to cytidine. PMID:6950393

Design of flat pneumatic artificial muscles

NASA Astrophysics Data System (ADS)

Wirekoh, Jackson; Park, Yong-Lae

2017-03-01

Pneumatic artificial muscles (PAMs) have gained wide use in the field of robotics due to their ability to generate linear forces and motions with a simple mechanism, while remaining lightweight and compact. However, PAMs are limited by their traditional cylindrical form factors, which must increase radially to improve contraction force generation. Additionally, this form factor results in overly complicated fabrication processes when embedded fibers and sensor elements are required to provide efficient actuation and control of the PAMs while minimizing the bulkiness of the overall robotic system. In order to overcome these limitations, a flat two-dimensional PAM capable of being fabricated using a simple layered manufacturing process was created. Furthermore, a theoretical model was developed using Von Karman’s formulation for large deformations and the energy methods. Experimental characterizations of two different types of PAMs, a single-cell unit and a multi-cell unit, were performed to measure the maximum contraction lengths and forces at input pressures ranging from 0 to 150 kPa. Experimental data were then used to verify the fidelity of the theoretical model.

The Effects of Pre- Versus Post-Presentation Input Flooding via Reading on the Young Iranian EFL Learners' Acquisition of Simple Past Tense

ERIC Educational Resources Information Center

Rikhtegar, Omid; Gholami, Javad

2015-01-01

The purpose of this study was to find out the possible effects of pre-versus post-presentation input flooding via reading on simple past tense acquisition among young Iranian EFL learners. Sixty one elementary EFL learners were divided into two experimental and one control group. The experimental groups were exposed to pre and post presentation…

The Limitations of Model-Based Experimental Design and Parameter Estimation in Sloppy Systems.

PubMed

White, Andrew; Tolman, Malachi; Thames, Howard D; Withers, Hubert Rodney; Mason, Kathy A; Transtrum, Mark K

2016-12-01

We explore the relationship among experimental design, parameter estimation, and systematic error in sloppy models. We show that the approximate nature of mathematical models poses challenges for experimental design in sloppy models. In many models of complex biological processes it is unknown what are the relevant physical mechanisms that must be included to explain system behaviors. As a consequence, models are often overly complex, with many practically unidentifiable parameters. Furthermore, which mechanisms are relevant/irrelevant vary among experiments. By selecting complementary experiments, experimental design may inadvertently make details that were ommitted from the model become relevant. When this occurs, the model will have a large systematic error and fail to give a good fit to the data. We use a simple hyper-model of model error to quantify a model's discrepancy and apply it to two models of complex biological processes (EGFR signaling and DNA repair) with optimally selected experiments. We find that although parameters may be accurately estimated, the discrepancy in the model renders it less predictive than it was in the sloppy regime where systematic error is small. We introduce the concept of a sloppy system-a sequence of models of increasing complexity that become sloppy in the limit of microscopic accuracy. We explore the limits of accurate parameter estimation in sloppy systems and argue that identifying underlying mechanisms controlling system behavior is better approached by considering a hierarchy of models of varying detail rather than focusing on parameter estimation in a single model.

Solar thermophotovoltaic system using nanostructures.

PubMed

Ungaro, Craig; Gray, Stephen K; Gupta, Mool C

2015-09-21

This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is both easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids.

Double quantum dot memristor

NASA Astrophysics Data System (ADS)

Li, Ying; Holloway, Gregory W.; Benjamin, Simon C.; Briggs, G. Andrew D.; Baugh, Jonathan; Mol, Jan A.

2017-08-01

Memristive systems are generalizations of memristors, which are resistors with memory. In this paper, we present a quantum description of quantum dot memristive systems. Using this model we propose and experimentally demonstrate a simple and practical scheme for realizing memristive systems with quantum dots. The approach harnesses a phenomenon that is commonly seen as a bane of nanoelectronics, i.e., switching of a trapped charge in the vicinity of the device. We show that quantum dot memristive systems have hysteresis current-voltage characteristics and quantum jump-induced stochastic behavior. While our experiment requires low temperatures, the same setup could, in principle, be realized with a suitable single-molecule transistor and operated at or near room temperature.

A validation study of the simulation software gprMax by varying antenna stand-off height

NASA Astrophysics Data System (ADS)

Wilkinson, Josh; Davidson, Nigel

2018-04-01

The design and subsequent testing of suitable antennas and of complete ground-penetrating radar (GPR) systems can be both time consuming and expensive, with the need to understand the performance of a system in realistic environments of great importance to the end user. Through the use of suitably validated simulations, these costs could be significantly reduced, allowing an economical capability to be built which can accurately predict the performance of novel GPR antennas and existing commercial-off-the-shelf (COTS) systems in a user defined environment. This paper focuses on a preliminary validation of the open source software gprMax1 which features the ability to custom define antennas, targets, clutter objects and realistic heterogeneous soils. As an initial step in the assessment of the software, a comparison of the modelled response of targets buried in sand to experimental data has been undertaken, with the variation in response with antenna stand-off height investigated. This was conducted for both a simple bespoke bow-tie antenna design as well as for a Geophysical Survey Systems, Inc. (GSSI) commercial system,2 building upon previous work3 which explored the fidelity of gprMax in reproducing the S11 of simple antenna designs.

COTS technologies for telemedicine applications.

PubMed

Triunfo, Riccardo; Tumbarello, Roberto; Sulis, Alessandro; Zanetti, Gianluigi; Lianas, Luca; Meloni, Vittorio; Frexia, Francesca

2010-01-01

To demonstrate a simple low-cost system for tele-echocardiology, focused on paediatric cardiology applications. The system was realized using open-source software and COTS technologies. It is based on the transmission of two simultaneous video streams, obtained by direct digitization of the output of an ultrasound machine and by a netcam showing the examination that is taking place. These streams are then embedded into a web page so they are accessible, together with basic video controls, via a standard web browser. The system can also record video streams on a server for further use. The system was tested on a small group of neonatal cases with suspected cardiopathies for a preliminary assessment of its features and diagnostic capabilities. Both the clinical and technological results were encouraging and are leading the way for further experimentation. The presented system can transfer clinical images and videos in an efficient way and in real time. It can be used in the same hospital to support internal consultancy requests, in remote areas using Internet connections and for didactic purposes using low cost COTS appliances and simple interfaces for end users. The solution proposed can be extended to control different medical appliances in those remote hospitals.

Anticipatory Cognitive Systems: a Theoretical Model

NASA Astrophysics Data System (ADS)

Terenzi, Graziano

This paper deals with the problem of understanding anticipation in biological and cognitive systems. It is argued that a physical theory can be considered as biologically plausible only if it incorporates the ability to describe systems which exhibit anticipatory behaviors. The paper introduces a cognitive level description of anticipation and provides a simple theoretical characterization of anticipatory systems on this level. Specifically, a simple model of a formal anticipatory neuron and a model (i.e. the τ-mirror architecture) of an anticipatory neural network which is based on the former are introduced and discussed. The basic feature of this architecture is that a part of the network learns to represent the behavior of the other part over time, thus constructing an implicit model of its own functioning. As a consequence, the network is capable of self-representation; anticipation, on a oscopic level, is nothing but a consequence of anticipation on a microscopic level. Some learning algorithms are also discussed together with related experimental tasks and possible integrations. The outcome of the paper is a formal characterization of anticipation in cognitive systems which aims at being incorporated in a comprehensive and more general physical theory.

Carbon dot-Au(i)Ag(0) assembly for the construction of an artificial light harvesting system.

PubMed

Jana, Jayasmita; Aditya, Teresa; Pal, Tarasankar

2018-03-06

Artificial light harvesting systems (LHS) with inorganic counterparts are considered to be robust as well as mechanistically simple, where the system follows the donor-acceptor principle with an unchanged structural pattern. Plasmonic gold or silver nanoparticles are mostly chosen as inorganic counterparts to design artificial LHS. To capitalize on its electron accepting capability, Au(i) has been considered in this work for the synergistic stabilization of a system with intriguingly fluorescing silver(0) clusters produced in situ. Thus a stable fluorescent Au(i)Ag(0) assembly is generated with electron accepting capabilities. On the other hand, carbon dots have evolved as new fluorescent probes due to their unique physicochemical properties. Utilizing the simple electronic behavior of carbon dots, an electronic interaction between the fluorescent Au(i)Ag(0) and a carbon dot has been investigated for the construction of a new artificial light harvesting system. This coinage metal assembly allows surface energy transfer where it acts as an acceptor, while the carbon dot behaves as a good donor. The energy transfer efficiency has been calculated experimentally to be significant (81.3%) and the Au(i)Ag(0)-carbon dot assembly paves the way for efficient artificial LHS.

New approach in the quantum statistical parton distribution

NASA Astrophysics Data System (ADS)

Sohaily, Sozha; Vaziri (Khamedi), Mohammad

2017-12-01

An attempt to find simple parton distribution functions (PDFs) based on quantum statistical approach is presented. The PDFs described by the statistical model have very interesting physical properties which help to understand the structure of partons. The longitudinal portion of distribution functions are given by applying the maximum entropy principle. An interesting and simple approach to determine the statistical variables exactly without fitting and fixing parameters is surveyed. Analytic expressions of the x-dependent PDFs are obtained in the whole x region [0, 1], and the computed distributions are consistent with the experimental observations. The agreement with experimental data, gives a robust confirm of our simple presented statistical model.

Single particle fluorescence: a simple experimental approach to evaluate coincidence effects.

PubMed

Wu, Xihong; Omenetto, Nicoló; Smith, Benjamin W; Winefordner, James D

2007-07-01

Real-time characterization of the chemical and physical properties of individual aerosol particles is an important issue in environmental studies. A well-established way of accomplishing this task relies on the use of laser-induced fluorescence or laser ionization mass spectrometry. We describe here a simple approach aimed at experimentally verifying that single particles are indeed addressed. The approach has been tested with a system consisting of a series of aerodynamic lenses to form a beam of dye-doped particles aerosolized from a solution of known concentration with a medical nebulizer. Two independent spectral detection channels simultaneously measure the fluorescence signals generated in two different spectral regions by the passage of a mixture of two dye-doped particles through a focused laser beam in a vacuum chamber. Coincidence effects, arising from the simultaneous observation of both fluorescence emissions, can then be directly observed. Both dual-color fluorescence and pulse height distribution have been analyzed. As expected, the probability of single- or multiple-particle interaction strongly depends on the particle flux in the chamber, which is related to the concentration of particles in the nebulized solution. In our case, to achieve a two-particle coincidence smaller than 10%, a particle concentration lower than 1.2x10(5) particles/mL is required. Moreover, it was found that the experimental observations are in agreement with a simple mathematical model based on Poisson statistics. Although the results obtained refer to particle concentrations in solution, our approach can equally be applicable to experiments involving direct air sampling, provided that the number density of particles in air can be measured a priori, e.g., with a particle counter.

Fast and precise thermoregulation system in physiological brain slice experiment

NASA Astrophysics Data System (ADS)

Sheu, Y. H.; Young, M. S.

1995-12-01

We have developed a fast and precise thermoregulation system incorporated within a physiological experiment on a brain slice. The thermoregulation system is used to control the temperature of a recording chamber in which the brain slice is placed. It consists of a single-chip microcomputer, a set command module, a display module, and an FLC module. A fuzzy control algorithm was developed and a fuzzy logic controller then designed for achieving fast, smooth thermostatic performance and providing precise temperature control with accuracy to 0.1 °C, from room temperature through 42 °C (experimental temperature range). The fuzzy logic controller is implemented by microcomputer software and related peripheral hardware circuits. Six operating modes of thermoregulation are offered with the system and this can be further extended according to experimental needs. The test results of this study demonstrate that the fuzzy control method is easily implemented by a microcomputer and also verifies that this method provides a simple way to achieve fast and precise high-performance control of a nonlinear thermoregulation system in a physiological brain slice experiment.

Experimental and numerical investigation of the nonlinear dynamics of compliant mechanisms for deployable structures

NASA Astrophysics Data System (ADS)

Dewalque, Florence; Schwartz, Cédric; Denoël, Vincent; Croisier, Jean-Louis; Forthomme, Bénédicte; Brüls, Olivier

2018-02-01

This paper studies the dynamics of tape springs which are characterised by a highly geometrical nonlinear behaviour including buckling, the formation of folds and hysteresis. An experimental set-up is designed to capture these complex nonlinear phenomena. The experimental data are acquired by the means of a 3D motion analysis system combined with a synchronised force plate. Deployment tests show that the motion can be divided into three phases characterised by different types of folds, frequencies of oscillation and damping behaviours. Furthermore, the reproducibility quality of the dynamic and quasi-static results is validated by performing a large number of tests. In parallel, a nonlinear finite element model is developed. The required model parameters are identified based on simple experimental tests such as static deformed configurations and small amplitude vibration tests. In the end, the model proves to be well correlated with the experimental results in opposite sense bending, while in equal sense, both the experimental set-up and the numerical model are particularly sensitive to the initial conditions.

Drainage fracture networks in elastic solids with internal fluid generation

NASA Astrophysics Data System (ADS)

Kobchenko, Maya; Hafver, Andreas; Jettestuen, Espen; Galland, Olivier; Renard, François; Meakin, Paul; Jamtveit, Bjørn; Dysthe, Dag K.

2013-06-01

Experiments in which CO2 gas was generated by the yeast fermentation of sugar in an elastic layer of gelatine gel confined between two glass plates are described and analyzed theoretically. The CO2 gas pressure causes the gel layer to fracture. The gas produced is drained on short length scales by diffusion and on long length scales by flow in a fracture network, which has topological properties that are intermediate between river networks and hierarchical-fracture networks. A simple model for the experimental system with two parameters that characterize the disorder and the intermediate (river-fracture) topology of the network was developed and the results of the model were compared with the experimental results.

Equipment for neutron measurements at VR-1 Sparrow training reactor.

PubMed

Kolros, Antonin; Huml, Ondrej; Kríz, Martin; Kos, Josef

2010-01-01

The VR-1 sparrow reactor is an experimental nuclear facility for training, student education and teaching purposes. The sparrow reactor is an educational platform for the basic experiments at the reactor physic and dosimetry. The aim of this article is to describe the new experimental equipment EMK310 features and possibilities for neutron detection by different gas filled detectors at VR-1 reactor. Among the EMK310 equipment typical attributes belong precise set-up, simple control, resistance to electromagnetic interference, high throughput (counting rate), versatility and remote controllability. The methods for non-linearity correction of pulse neutron detection system and reactimeter application are presented. Copyright 2009. Published by Elsevier Ltd.

Experimental and rendering-based investigation of laser radar cross sections of small unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Laurenzis, Martin; Bacher, Emmanuel; Christnacher, Frank

2017-12-01

Laser imaging systems are prominent candidates for detection and tracking of small unmanned aerial vehicles (UAVs) in current and future security scenarios. Laser reflection characteristics for laser imaging (e.g., laser gated viewing) of small UAVs are investigated to determine their laser radar cross section (LRCS) by analyzing the intensity distribution of laser reflection in high resolution images. For the first time, LRCSs are determined in a combined experimental and computational approaches by high resolution laser gated viewing and three-dimensional rendering. An optimized simple surface model is calculated taking into account diffuse and specular reflectance properties based on the Oren-Nayar and the Cook-Torrance reflectance models, respectively.

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam.

PubMed

Warwick, J; Dzelzainis, T; Dieckmann, M E; Schumaker, W; Doria, D; Romagnani, L; Poder, K; Cole, J M; Alejo, A; Yeung, M; Krushelnick, K; Mangles, S P D; Najmudin, Z; Reville, B; Samarin, G M; Symes, D D; Thomas, A G R; Borghesi, M; Sarri, G

2017-11-03

We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥1  T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of ε_{B}≈10^{-3} is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

NASA Astrophysics Data System (ADS)

Warwick, J.; Dzelzainis, T.; Dieckmann, M. E.; Schumaker, W.; Doria, D.; Romagnani, L.; Poder, K.; Cole, J. M.; Alejo, A.; Yeung, M.; Krushelnick, K.; Mangles, S. P. D.; Najmudin, Z.; Reville, B.; Samarin, G. M.; Symes, D. D.; Thomas, A. G. R.; Borghesi, M.; Sarri, G.

2017-11-01

We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥1 T ) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of ɛB≈10-3 is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.

Achilles tendon reflex measuring system

NASA Astrophysics Data System (ADS)

Szebeszczyk, Janina; Straszecka, Joanna

1995-06-01

The examination of Achilles tendon reflex is widely used as a simple, noninvasive clinical test in diagnosis and pharmacological therapy monitoring in such diseases as: hypothyroidism, hyperthyroidism, diabetic neuropathy, the lower limbs obstructive angiopathies and intermittent claudication. Presented Achilles tendon reflect measuring system is based on the piezoresistive sensor connected with the cylinder-piston system. To determinate the moment of Achilles tendon stimulation a detecting circuit was used. The outputs of the measuring system are connected to the PC-based data acquisition board. Experimental results showed that the measurement accuracy and repeatability is good enough for diagnostics and therapy monitoring purposes. A user friendly, easy-to-operate measurement system fulfills all the requirements related to recording, presentation and storing of the patients' reflexograms.

Dynamic Investigation of Static Divergence: Analysis and Testing

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

2000-01-01

The phenomenon known as aeroelastic divergence is the focus of this work. The analyses and experiment presented here show that divergence can occur without a structural dynamic mode losing its oscillatory nature. Aeroelastic divergence occurs when the structural restorative capability or stiffness of a structure is overwhelmed by the static aerodynamic moment. This static aeroelastic coupling does not require the structural dynamic system behavior to cease, however. Aeroelastic changes in the dynamic mode behavior are governed not only by the stiffness, but by damping and inertial properties. The work presented here supports these fundamental assertions by examining a simple system: a typical section airfoil with only a rotational structural degree of freedom. Analytical results identified configurations that exhibit different types of dynamic mode behavior as the system encounters divergence. A wind tunnel model was designed and tested to examine divergence experimentally. The experimental results validate the analytical calculations and explicitly examine the divergence phenomenon where the dynamic mode persists. Three configurations of the wind tunnel model were tested. The experimental results agree very well with the analytical predictions of subcritical characteristics, divergence velocity, and behavior of the noncritical dynamic mode at divergence.

Gain-Scheduled Complementary Filter Design for a MEMS Based Attitude and Heading Reference System

PubMed Central

Yoo, Tae Suk; Hong, Sung Kyung; Yoon, Hyok Min; Park, Sungsu

2011-01-01

This paper describes a robust and simple algorithm for an attitude and heading reference system (AHRS) based on low-cost MEMS inertial and magnetic sensors. The proposed approach relies on a gain-scheduled complementary filter, augmented by an acceleration-based switching architecture to yield robust performance, even when the vehicle is subject to strong accelerations. Experimental results are provided for a road captive test during which the vehicle dynamics are in high-acceleration mode and the performance of the proposed filter is evaluated against the output from a conventional linear complementary filter. PMID:22163824

Virtual Induction Loops Based on Cooperative Vehicular Communications

PubMed Central

Gramaglia, Marco; Bernardos, Carlos J.; Calderon, Maria

2013-01-01

Induction loop detectors have become the most utilized sensors in traffic management systems. The gathered traffic data is used to improve traffic efficiency (i.e., warning users about congested areas or planning new infrastructures). Despite their usefulness, their deployment and maintenance costs are expensive. Vehicular networks are an emerging technology that can support novel strategies for ubiquitous and more cost-effective traffic data gathering. In this article, we propose and evaluate VIL (Virtual Induction Loop), a simple and lightweight traffic monitoring system based on cooperative vehicular communications. The proposed solution has been experimentally evaluated through simulation using real vehicular traces. PMID:23348033

Slip control for LIM propelled transit vehicles

NASA Astrophysics Data System (ADS)

Wallace, A. K.; Parker, J. H.; Dawson, G. E.

1980-09-01

Short stator linear induction motors, with an iron-backed aluminum sheet reaction rail and powered by a controlled inverter, have been selected as the propulsion system for transit vehicles in an intermediate capacity system (12-20,000 pphpd). The linear induction motor is capable of adhesion independent braking and acceleration levels which permit safe, close headways. In addition, simple control is possible allowing moving block automatic train control. This paper presents a slip frequency control scheme for the LIM. Experimental results for motoring and braking obtained from a test vehicle are also presented. These values are compared with theoretical predictions.

Response of a small-turboshaft-engine compression system to inlet temperature distortion

NASA Technical Reports Server (NTRS)

Biesiadny, T. J.; Klann, G. A.; Little, J. K.

1984-01-01

An experimental investigation was conducted into the response of a small-turboshaft-engine compression system to steady-state and transient inlet temperature distortions. Transient temperature ramps range from less than 100 K/sec to above 610 K/sec and generated instantaneous temperatures to 420 K above ambient. Steady-state temperature distortion levels were limited by the engine hardware temperature list. Simple analysis of the steady-state distortion data indicated that a particle separator at the engine inlet permitted higher levels of temperature distortion before onset of compressor surge than would be expected without the separator.

Measurement techniques for analysis of fission fragment excited gases

NASA Technical Reports Server (NTRS)

Schneider, R. T.; Carroll, E. E.; Davis, J. F.; Davie, R. N.; Maguire, T. C.; Shipman, R. G.

1976-01-01

Spectroscopic analysis of fission fragment excited He, Ar, Xe, N2, Ne, Ar-N2, and Ne-N2 have been conducted. Boltzmann plot analysis of He, Ar and Xe have indicated a nonequilibrium, recombining plasma, and population inversions have been found in these gases. The observed radiating species in helium have been adequately described by a simple kinetic model. A more extensive model for argon, nitrogen and Ar-N2 mixtures was developed which adequately describes the energy flow in the system and compares favorably with experimental measurements. The kinetic processes involved in these systems are discussed.

Quantitative polarized light microscopy using spectral multiplexing interferometry.

PubMed

Li, Chengshuai; Zhu, Yizheng

2015-06-01

We propose an interferometric spectral multiplexing method for measuring birefringent specimens with simple configuration and high sensitivity. The retardation and orientation of sample birefringence are simultaneously encoded onto two spectral carrier waves, generated interferometrically by a birefringent crystal through polarization mixing. A single interference spectrum hence contains sufficient information for birefringence determination, eliminating the need for mechanical rotation or electrical modulation. The technique is analyzed theoretically and validated experimentally on cellulose film. System simplicity permits the possibility of mitigating system birefringence background. Further analysis demonstrates the technique's exquisite sensitivity as high as ∼20  pm for retardation measurement.

Interstitial-phase precipitation in iron-base alloys: a comparative study

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

Pelton, A.R.

1982-06-01

Recent developments have elucidated the atomistic mechanisms of precipitation of interstitial elements in simple alloy systems. However, in the more technologically important iron base alloys, interstitial phase precipitation is generally not well understood. The present experimental study was therefore designed to test the applicability of these concepts to more complex ferrous alloys. Hence, a comparative study was made of interstitial phase precipitation in ferritic Fe-Si-C and in austenitic phosphorus-containing Fe-Cr-Ni steels. These systems were subjected to a variety of quench-age thermal treatments, and the microstructural development was subsequently characterized by transmission electron microscopy.

Modeling, system identification, and control of ASTREX

NASA Technical Reports Server (NTRS)

Abhyankar, Nandu S.; Ramakrishnan, J.; Byun, K. W.; Das, A.; Cossey, Derek F.; Berg, J.

1993-01-01

The modeling, system identification and controller design aspects of the ASTREX precision space structure are presented in this work. Modeling of ASTREX is performed using NASTRAN, TREETOPS and I-DEAS. The models generated range from simple linear time-invariant models to nonlinear models used for large angle simulations. Identification in both the time and frequency domains are presented. The experimental set up and the results from the identification experiments are included. Finally, controller design for ASTREX is presented. Simulation results using this optimal controller demonstrate the controller performance. Finally the future directions and plans for the facility are addressed.

Coupled electromagnetic-thermodynamic simulations of microwave heating problems using the FDTD algorithm.

PubMed

Kopyt, Paweł; Celuch, Małgorzata

2007-01-01

A practical implementation of a hybrid simulation system capable of modeling coupled electromagnetic-thermodynamic problems typical in microwave heating is described. The paper presents two approaches to modeling such problems. Both are based on an FDTD-based commercial electromagnetic solver coupled to an external thermodynamic analysis tool required for calculations of heat diffusion. The first approach utilizes a simple FDTD-based thermal solver while in the second it is replaced by a universal commercial CFD solver. The accuracy of the two modeling systems is verified against the original experimental data as well as the measurement results available in literature.

Inverter design for high frequency power distribution

NASA Technical Reports Server (NTRS)

King, R. J.

1985-01-01

A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

A system for intelligent teleoperation research

NASA Technical Reports Server (NTRS)

Orlando, N. E.

1983-01-01

The Automation Technology Branch of NASA Langley Research Center is developing a research capability in the field of artificial intelligence, particularly as applicable in teleoperator/robotics development for remote space operations. As a testbed for experimentation in these areas, a system concept has been developed and is being implemented. This system termed DAISIE (Distributed Artificially Intelligent System for Interacting with the Environment), interfaces the key processes of perception, reasoning, and manipulation by linking hardware sensors and manipulators to a modular artificial intelligence (AI) software system in a hierarchical control structure. Verification experiments have been performed: one experiment used a blocksworld database and planner embedded in the DAISIE system to intelligently manipulate a simple physical environment; the other experiment implemented a joint-space collision avoidance algorithm. Continued system development is planned.

On the analysis of photo-electron spectra

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

Gao, C.-Z., E-mail: gao@irsamc.ups-tlse.fr; CNRS, LPT; Dinh, P.M.

2015-09-15

We analyze Photo-Electron Spectra (PES) for a variety of excitation mechanisms from a simple mono-frequency laser pulse to involved combination of pulses as used, e.g., in attosecond experiments. In the case of simple pulses, the peaks in PES reflect the occupied single-particle levels in combination with the given laser frequency. This usual, simple rule may badly fail in the case of excitation pulses with mixed frequencies and if resonant modes of the system are significantly excited. We thus develop an extension of the usual rule to cover all possible excitation scenarios, including mixed frequencies in the attosecond regime. We find thatmore » the spectral distributions of dipole, monopole and quadrupole power for the given excitation taken together and properly shifted by the single-particle energies provide a pertinent picture of the PES in all situations. This leads to the derivation of a generalized relation allowing to understand photo-electron yields even in complex experimental setups.« less

Chaotic He-Ne laser

NASA Astrophysics Data System (ADS)

Kuusela, Tom A.

2017-09-01

A He-Ne laser is an example of a class A laser, which can be described by a single nonlinear differential equation of the complex electric field. This laser system has only one degree of freedom and is thus inherently stable. A He-Ne laser can be driven to the chaotic condition when a large fraction of the output beam is injected back to the laser. In practice, this can be done simply by adding an external mirror. In this situation, the laser system has infinite degrees of freedom and therefore it can have a chaotic attractor. We show the fundamental laser equations and perform elementary stability analysis. In experiments, the laser intensity variations are measured by a simple photodiode circuit. The laser output intensity time series is studied using nonlinear analysis tools which can be found freely on the internet. The results show that the laser system with feedback has an attractor of a reasonably high dimension and that the maximal Lyapunov exponent is positive, which is clear evidence of chaotic behaviour. The experimental setup and analysis steps are so simple that the studies can even be implemented in the undergraduate physics laboratory.

Validation of a pair of computer codes for estimation and optimization of subsonic aerodynamic performance of simple hinged-flap systems for thin swept wings

NASA Technical Reports Server (NTRS)

Carlson, Harry W.; Darden, Christine M.

1988-01-01

Extensive correlations of computer code results with experimental data are employed to illustrate the use of linearized theory attached flow methods for the estimation and optimization of the aerodynamic performance of simple hinged flap systems. Use of attached flow methods is based on the premise that high levels of aerodynamic efficiency require a flow that is as nearly attached as circumstances permit. A variety of swept wing configurations are considered ranging from fighters to supersonic transports, all with leading- and trailing-edge flaps for enhancement of subsonic aerodynamic efficiency. The results indicate that linearized theory attached flow computer code methods provide a rational basis for the estimation and optimization of flap system aerodynamic performance at subsonic speeds. The analysis also indicates that vortex flap design is not an opposing approach but is closely related to attached flow design concepts. The successful vortex flap design actually suppresses the formation of detached vortices to produce a small vortex which is restricted almost entirely to the leading edge flap itself.

PLDAPS: A Hardware Architecture and Software Toolbox for Neurophysiology Requiring Complex Visual Stimuli and Online Behavioral Control.

PubMed

Eastman, Kyler M; Huk, Alexander C

2012-01-01

Neurophysiological studies in awake, behaving primates (both human and non-human) have focused with increasing scrutiny on the temporal relationship between neural signals and behaviors. Consequently, laboratories are often faced with the problem of developing experimental equipment that can support data recording with high temporal precision and also be flexible enough to accommodate a wide variety of experimental paradigms. To this end, we have developed a MATLAB toolbox that integrates several modern pieces of equipment, but still grants experimenters the flexibility of a high-level programming language. Our toolbox takes advantage of three popular and powerful technologies: the Plexon apparatus for neurophysiological recordings (Plexon, Inc., Dallas, TX, USA), a Datapixx peripheral (Vpixx Technologies, Saint-Bruno, QC, Canada) for control of analog, digital, and video input-output signals, and the Psychtoolbox MATLAB toolbox for stimulus generation (Brainard, 1997; Pelli, 1997; Kleiner et al., 2007). The PLDAPS ("Platypus") system is designed to support the study of the visual systems of awake, behaving primates during multi-electrode neurophysiological recordings, but can be easily applied to other related domains. Despite its wide range of capabilities and support for cutting-edge video displays and neural recording systems, the PLDAPS system is simple enough for someone with basic MATLAB programming skills to design their own experiments.

Magnetic domain-wall tilting due to domain-wall speed asymmetry

NASA Astrophysics Data System (ADS)

Kim, Dae-Yun; Park, Min-Ho; Park, Yong-Keun; Kim, Joo-Sung; Nam, Yoon-Seok; Hwang, Hyun-Seok; Kim, Duck-Ho; Je, Soong-Geun; Min, Byoung-Chul; Choe, Sug-Bong

2018-04-01

Broken symmetries in diverse systems generate a number of intriguing phenomena and the analysis on such broken symmetries often provides decisive clues for exploring underlying physics in the systems. Recently, in magnetic thin-film systems, the Dzyaloshinskii-Moriya interaction (DMI)—induced by the broken symmetry of structural inversion—accounts for various chiral phenomena, which are of timely issues in spintronics. Here, we report an experimental observation on unexpected tilting of magnetic domain walls (DWs) due to the broken symmetry under the application of the magnetic field transverse to the magnetic wire systems. It has been predicted that the DMI possibly causes such DW tilting in the direction of the energy minimization. However, very interestingly, experimental observation reveals that the DW tilting does not follow the prediction based on the energy minimization, even for the tilting direction. Instead, the DW tilting is governed by the DW speed asymmetry that is initiated by the DW pinning at wire edges. A simple analytic model is proposed in consideration of the DW speed asymmetry at wire edges, which successfully explains the experimental observation of the DW tilting directions and angles, as confirmed by numerical simulation. The present study manifests the decisive role of the DW pinning with the DW speed asymmetry, which determines the DW configuration and consequently, the dynamics.

PubSearch and PubFetch: a simple management system for semiautomated retrieval and annotation of biological information from the literature.

PubMed

Yoo, Danny; Xu, Iris; Berardini, Tanya Z; Rhee, Seung Yon; Narayanasamy, Vijay; Twigger, Simon

2006-03-01

For most systems in biology, a large body of literature exists that describes the complexity of the system based on experimental results. Manual review of this literature to extract targeted information into biological databases is difficult and time consuming. To address this problem, we developed PubSearch and PubFetch, which store literature, keyword, and gene information in a relational database, index the literature with keywords and gene names, and provide a Web user interface for annotating the genes from experimental data found in the associated literature. A set of protocols is provided in this unit for installing, populating, running, and using PubSearch and PubFetch. In addition, we provide support protocols for performing controlled vocabulary annotations. Intended users of PubSearch and PubFetch are database curators and biology researchers interested in tracking the literature and capturing information about genes of interest in a more effective way than with conventional spreadsheets and lab notebooks.

Measurement and compensation schemes for the pulse front distortion of ultra-intensity ultra-short laser pulses

NASA Astrophysics Data System (ADS)

Wu, Fenxiang; Xu, Yi; Yu, Linpeng; Yang, Xiaojun; Li, Wenkai; Lu, Jun; Leng, Yuxin

2016-11-01

Pulse front distortion (PFD) is mainly induced by the chromatic aberration in femtosecond high-peak power laser systems, and it can temporally distort the pulse in the focus and therefore decrease the peak intensity. A novel measurement scheme is proposed to directly measure the PFD of ultra-intensity ultra-short laser pulses, which can work not only without any extra struggle for the desired reference pulse, but also largely reduce the size of the required optical elements in measurement. The measured PFD in an experimental 200TW/27fs laser system is in good agreement with the calculated result, which demonstrates the validity and feasibility of this method effectively. In addition, a simple compensation scheme based on the combination of concave lens and parabolic lens is also designed and proposed to correct the PFD. Based on the theoretical calculation, the PFD of above experimental laser system can almost be completely corrected by using this compensator with proper parameters.

Causal Modeling the Delayed-Choice Experiment

NASA Astrophysics Data System (ADS)

Chaves, Rafael; Lemos, Gabriela Barreto; Pienaar, Jacques

2018-05-01

Wave-particle duality has become one of the flagships of quantum mechanics. This counterintuitive concept is highlighted in a delayed-choice experiment, where the experimental setup that reveals either the particle or wave nature of a quantum system is decided after the system has entered the apparatus. Here we consider delayed-choice experiments from the perspective of device-independent causal models and show their equivalence to a prepare-and-measure scenario. Within this framework, we consider Wheeler's original proposal and its variant using a quantum control and show that a simple classical causal model is capable of reproducing the quantum mechanical predictions. Nonetheless, among other results, we show that, in a slight variant of Wheeler's gedanken experiment, a photon in an interferometer can indeed generate statistics incompatible with any nonretrocausal hidden variable model, whose dimensionality is the same as that of the quantum system it is supposed to mimic. Our proposal tolerates arbitrary losses and inefficiencies, making it specially suited to loophole-free experimental implementations.

Customization of ¹³C-MFA strategy according to cell culture system.

PubMed

Quek, Lake-Ee; Nielsen, Lars K

2014-01-01

(13)C-MFA is far from being a simple assay for quantifying metabolic activity. It requires considerable up-front experimental planning and familiarity with the cell culture system in question, as well as optimized analytics and adequate computation frameworks. The success of a (13)C-MFA experiment is ultimately rated by the ability to accurately quantify the flux of one or more reactions of interest. In this chapter, we describe the different (13)C-MFA strategies that have been developed for the various fermentation or cell culture systems, as well as the limitations of the respective strategies. The strategies are affected by many factors and the (13)C-MFA modeling and experimental strategy must be tailored to conditions. The prevailing philosophy in the computation process is that any metabolic processes that produce significant systematic bias in the labeling pattern of the metabolites being measured must be described in the model. It is equally important to plan a labeling strategy by analytical screening or by heuristics.

The data sharing advantage in astrophysics

NASA Astrophysics Data System (ADS)

Dorch, Bertil F.; Drachen, Thea M.; Ellegaard, Ole

2016-10-01

We present here evidence for the existence of a citation advantage within astrophysics for papers that link to data. Using simple measures based on publication data from NASA Astrophysics Data System we find a citation advantage for papers with links to data receiving on the average significantly more citations per paper than papers without links to data. Furthermore, using INSPEC and Web of Science databases we investigate whether either papers of an experimental or theoretical nature display different citation behavior.

Exploring the atmosphere using smartphones

NASA Astrophysics Data System (ADS)

Monteiro, Martín; Vogt, Patrik; Stari, Cecilia; Cabeza, Cecilia; Marti, Arturo C.

2016-05-01

The characteristics of the inner layer of the atmosphere, the troposphere, are determinant for Earth's life. In this experience we explore the first hundreds of meters using a smartphone mounted on a quadcopter. Both the altitude and the pressure are obtained using the smartphone's sensors. We complement these measures with data collected from the flight information system of an aircraft. The experimental results are compared with the International Standard Atmosphere and other simple approximations: isothermal and constant density atmospheres.

Bayesian Inference for Source Term Estimation: Application to the International Monitoring System Radionuclide Network

DTIC Science & Technology

2014-10-01

de l’exactitude et de la précision), comparativement au modèle de mesure plus simple qui n’utilise pas de multiplicateurs. Importance pour la défense...3) Bayesian experimental design for receptor placement in order to maximize the expected information in the measured concen- tration data for...applications of the Bayesian inferential methodology for source recon- struction have used high-quality concentration data from well- designed atmospheric

Diffraction-Based Density Restraints for Membrane and Membrane-Peptide Molecular Dynamics Simulations

PubMed Central

Benz, Ryan W.; Nanda, Hirsh; Castro-Román, Francisco; White, Stephen H.; Tobias, Douglas J.

2006-01-01

We have recently shown that current molecular dynamics (MD) atomic force fields are not yet able to produce lipid bilayer structures that agree with experimentally-determined structures within experimental errors. Because of the many advantages offered by experimentally validated simulations, we have developed a novel restraint method for membrane MD simulations that uses experimental diffraction data. The restraints, introduced into the MD force field, act upon specified groups of atoms to restrain their mean positions and widths to values determined experimentally. The method was first tested using a simple liquid argon system, and then applied to a neat dioleoylphosphatidylcholine (DOPC) bilayer at 66% relative humidity and to the same bilayer containing the peptide melittin. Application of experiment-based restraints to the transbilayer double-bond and water distributions of neat DOPC bilayers led to distributions that agreed with the experimental values. Based upon the experimental structure, the restraints improved the simulated structure in some regions while introducing larger differences in others, as might be expected from imperfect force fields. For the DOPC-melittin system, the experimental transbilayer distribution of melittin was used as a restraint. The addition of the peptide caused perturbations of the simulated bilayer structure, but which were larger than observed experimentally. The melittin distribution of the simulation could be fit accurately to a Gaussian with parameters close to the observed ones, indicating that the restraints can be used to produce an ensemble of membrane-bound peptide conformations that are consistent with experiments. Such ensembles pave the way for understanding peptide-bilayer interactions at the atomic level. PMID:16950837

Experimental Verification of Electric Drive Technologies Based on Artificial Intelligence Tools

NASA Technical Reports Server (NTRS)

Rubaai, Ahmed; Ricketts, Daniel; Kotaru, Raj; Thomas, Robert; Noga, Donald F. (Technical Monitor); Kankam, Mark D. (Technical Monitor)

2000-01-01

In this report, a fully integrated prototype of a flight servo control system is successfully developed and implemented using brushless dc motors. The control system is developed by the fuzzy logic theory, and implemented with a multilayer neural network. First, a neural network-based architecture is introduced for fuzzy logic control. The characteristic rules and their membership functions of fuzzy systems are represented as the processing nodes in the neural network structure. The network structure and the parameter learning are performed simultaneously and online in the fuzzy-neural network system. The structure learning is based on the partition of input space. The parameter learning is based on the supervised gradient decent method, using a delta adaptation law. Using experimental setup, the performance of the proposed control system is evaluated under various operating conditions. Test results are presented and discussed in the report. The proposed learning control system has several advantages, namely, simple structure and learning capability, robustness and high tracking performance and few nodes at hidden layers. In comparison with the PI controller, the proposed fuzzy-neural network system can yield a better dynamic performance with shorter settling time, and without overshoot. Experimental results have shown that the proposed control system is adaptive and robust in responding to a wide range of operating conditions. In summary, the goal of this study is to design and implement-advanced servosystems to actuate control surfaces for flight vehicles, namely, aircraft and helicopters, missiles and interceptors, and mini- and micro-air vehicles.

Safe drinking water and clean air: an experimental study evaluating the concept of combining household water treatment and indoor air improvement using the Water Disinfection Stove (WADIS).

PubMed

Christen, Andri; Navarro, Carlos Morante; Mäusezahl, Daniel

2009-09-01

Indoor air pollution and unsafe water remain two of the most important environmental risk factors for the global burden of infectious diseases. Improved stoves and household water treatment (HWT) methods represent two of the most effective interventions to fight respiratory and diarrhoeal illnesses at household level. Since new improved stoves are highly accepted and HWT methods have their drawbacks regarding sustained use, combining the two interventions in one technical solution could result in notable positive convenience and health benefits. A WAter DIsinfection Stove (WADIS) based on a Lorena-stove design with a simple flow-through boiling water-treatment system was developed and tested by a pilot experimental study in rural Bolivia. The results of a post-implementation evaluation of two WADIS and 27 Lorena-stoves indicate high social acceptance rather due to convenience gains of the stove than to perceived health improvements. The high efficacy of the WADIS-water treatment system, with a reduction of microbiological contamination load in the treated water from 87600 thermotolerant coliform colony forming units per 100mL (CFU/100mL) to zero is indicative. The WADIS concept unifies two interventions addressing two important global burdens of disease. WADIS' simple design, relying on locally available materials and low manufacturing costs (approx. 6 US) indicates potential for spontaneous diffusion and scaling up.

Check the Lambert-Beer-Bouguer law: a simple trick to boost the confidence of students toward both exponential laws and the discrete approach to experimental physics

NASA Astrophysics Data System (ADS)

Di Capua, R.; Offi, F.; Fontana, F.

2014-07-01

Exponential decay is a prototypical functional behaviour for many physical phenomena, and therefore it deserves great attention in physics courses at an academic level. The absorption of the electromagnetic radiation that propagates in a dissipative medium provides an example of the decay of light intensity, as stated by the law of Lambert-Beer-Bourguer. We devised a very simple experiment to check this law. The experimental setup, its realization, and the data analysis of the experiment are definitely simple. Our main goal was to create an experiment that is accessible to all students, including those in their first year of academic courses and those with poorly equipped laboratories. As illustrated in this paper, our proposal allowed us to develop a deep discussion about some general mathematical and numerical features of exponential decay. Furthermore, the special setup of the absorbing medium (sliced in finite thickness slabs) and the experimental outcomes allow students to understand the transition from the discrete to the continuum approach in experimental physics.

Seeking maximum linearity of transfer functions

NASA Astrophysics Data System (ADS)

Silva, Filipi N.; Comin, Cesar H.; Costa, Luciano da F.

2016-12-01

Linearity is an important and frequently sought property in electronics and instrumentation. Here, we report a method capable of, given a transfer function (theoretical or derived from some real system), identifying the respective most linear region of operation with a fixed width. This methodology, which is based on least squares regression and systematic consideration of all possible regions, has been illustrated with respect to both an analytical (sigmoid transfer function) and a simple situation involving experimental data of a low-power, one-stage class A transistor current amplifier. Such an approach, which has been addressed in terms of transfer functions derived from experimentally obtained characteristic surface, also yielded contributions such as the estimation of local constants of the device, as opposed to typically considered average values. The reported method and results pave the way to several further applications in other types of devices and systems, intelligent control operation, and other areas such as identifying regions of power law behavior.

NEW MODEL AND MEASUREMENT PRINCIPLE OF FLOWING AND HEAT TRANSFER CHARACTERISTICS OF REGENERATOR

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

Chen, Y. Y.; Graduate University of the Chinese Academy of Sciences, Beijing, 100049; Luo, E. C.

2008-03-16

Regenerators play key role in oscillating-flow cryocoolers or thermoacoustic heat engine systems. However, their flowing and heat transfer mechanism is still not well understood. The complexities of the oscillating flow regenerator make traditional method of heat transfer research become difficult or helpless. In this paper, a model for porous media regenerator was given based on the linear thermoacoustic theory. Then the correlations for characteristic parameters were obtained by deducing universal expressions for thermoacoustic viscous function F{sub v} and thermal function F{sub T}. A simple acoustical method and experimental system to get F{sub v} and F{sub T} via measurements of isothermalmore » regenerators were presented. Some measurements of packed stainless screen regenerators were performed, and preliminary experimental results for flow and convective coefficients were derived, which showing flowing friction factor is approximately within 132/Re to 173/Re.« less

Experimental exploration of the Mulliken-Hush relationship for intramolecular electron transfer reactions.

PubMed

Mukherjee, Tamal; Ito, Naoki; Gould, Ian R

2011-03-17

The Mulliken-Hush (M-H) relationship provides the critical link between optical and thermal electron transfer processes, and yet very little direct experimental support for its applicability has been provided. Dicyanovinylazaadamantane (DCVA) represents a simple two-state (neutral/charge-transfer) intramolecular electron transfer system that exhibits charge-transfer absorption and emission spectra that are readily measurable in solvents with a wide range of polarities. In this regard it represents an ideal model system for studying the factors that control both optical charge separation (absorption) and recombination (emission) processes in solution. Here we explore the applicability of the M-H relation to quantitative descriptions of the optical charge-transfer processes in DCVA. For DCVA, the measured radiative rate constants exhibit a linear dependence on transition energy, and transition dipole moments exhibit an inverse dependence on transition energy, consistent with the M-H relationship.

A simple and accurate method for calculation of the structure factor of interacting charged spheres.

PubMed

Wu, Chu; Chan, Derek Y C; Tabor, Rico F

2014-07-15

Calculation of the structure factor of a system of interacting charged spheres based on the Ginoza solution of the Ornstein-Zernike equation has been developed and implemented on a stand-alone spreadsheet. This facilitates direct interactive numerical and graphical comparisons between experimental structure factors with the pioneering theoretical model of Hayter-Penfold that uses the Hansen-Hayter renormalisation correction. The method is used to fit example experimental structure factors obtained from the small-angle neutron scattering of a well-characterised charged micelle system, demonstrating that this implementation, available in the supplementary information, gives identical results to the Hayter-Penfold-Hansen approach for the structure factor, S(q) and provides direct access to the pair correlation function, g(r). Additionally, the intermediate calculations and outputs can be readily accessed and modified within the familiar spreadsheet environment, along with information on the normalisation procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

Simple electrical model and initial experiments for intra-body communications.

PubMed

Gao, Y M; Pun, S H; Du, M; Mak, P U; Vai, M I

2009-01-01

Intra-Body Communication(IBC) is a short range "wireless" communication technique appeared in recent years. This technique relies on the conductive property of human tissue to transmit the electric signal among human body. This is beneficial for devices networking and sensors among human body, and especially suitable for wearable sensors, telemedicine system and home health care system as in general the data rates of physiologic parameters are low. In this article, galvanic coupling type IBC application on human limb was investigated in both its mathematical model and related experiments. The experimental results showed that the proposed mathematical model was capable in describing the galvanic coupling type IBC under low frequency. Additionally, the calculated result and experimental result also indicated that the electric signal induced by the transmitters of IBC can penetrate deep into human muscle and thus, provide an evident that IBC is capable of acting as networking technique for implantable devices.

Free-space laser communication technologies IV; Proceedings of the 4th Conference, Los Angeles, CA, Jan. 23, 24, 1992

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1992-01-01

Papers included in this volume are grouped under topics of receivers; laser transmitters; components; system analysis, performance, and applications; and beam control (pointing, acquisition, and tracking). Papers are presented on an experimental determination of power penalty contributions in an optical Costas-type phase-locked loop receiver, a resonant laser receiver for free-space laser communications, a simple low-loss technique for frequency-locking lasers, direct phase modulation of laser diodes, and a silex beacon. Particular attention is given to experimental results on an optical array antenna for nonmechanical beam steering, a potassium Faraday anomalous dispersion optical filter, a 100-Mbps resonant cavity phase modulator for coherent optical communications, a numerical simulation of a 325-Mbit/s QPPM optical communication system, design options for an optical multiple-access data relay terminal, CCD-based optical tracking loop design trades, and an analysis of a spatial-tracking subsystem for optical communications.

Technical Note: Procedure for the calibration and validation of kilo-voltage cone-beam CT models

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

Vilches-Freixas, Gloria; Létang, Jean Michel; Rit,

2016-09-15

Purpose: The aim of this work is to propose a general and simple procedure for the calibration and validation of kilo-voltage cone-beam CT (kV CBCT) models against experimental data. Methods: The calibration and validation of the CT model is a two-step procedure: the source model then the detector model. The source is described by the direction dependent photon energy spectrum at each voltage while the detector is described by the pixel intensity value as a function of the direction and the energy of incident photons. The measurements for the source consist of a series of dose measurements in air performedmore » at each voltage with varying filter thicknesses and materials in front of the x-ray tube. The measurements for the detector are acquisitions of projection images using the same filters and several tube voltages. The proposed procedure has been applied to calibrate and assess the accuracy of simple models of the source and the detector of three commercial kV CBCT units. If the CBCT system models had been calibrated differently, the current procedure would have been exclusively used to validate the models. Several high-purity attenuation filters of aluminum, copper, and silver combined with a dosimeter which is sensitive to the range of voltages of interest were used. A sensitivity analysis of the model has also been conducted for each parameter of the source and the detector models. Results: Average deviations between experimental and theoretical dose values are below 1.5% after calibration for the three x-ray sources. The predicted energy deposited in the detector agrees with experimental data within 4% for all imaging systems. Conclusions: The authors developed and applied an experimental procedure to calibrate and validate any model of the source and the detector of a CBCT unit. The present protocol has been successfully applied to three x-ray imaging systems. The minimum requirements in terms of material and equipment would make its implementation suitable in most clinical environments.« less

A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater.

PubMed

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza

2016-04-01

A simple and sensitive flow injection chemiluminescence (CL) method in which CdS quantum dots (QDs) enhanced the CL intensity of a KMnO4-formaldehyde (HCHO) reaction was offered for the determination of HCHO. This CL system was based on the catalytic activity of CdS QDs and their participation in the CL resonance energy transfer (CRET) phenomenon. A possible mechanism for the supplied CL system was proposed using the kinetic curves of the CL systems and the spectra of CL, photoluminescence (PL) and ultraviolet-visible (UV-Vis). The emanated CL intensity of the KMnO4-CdS QDs system was amplified in the presence of a trace level of HCHO. Based on this enhancement effect, a simple and sensitive flow injection CL method was suggested for the determination of HCHO concentration in environmental water and wastewater samples. Under selected optimized experimental conditions, the increased CL intensity was proportional to the HCHO concentration in the range of 0.03-4.5 μg L(-1) and 4.5-10.0 μg L(-1). The detection limits (3σ) were 0.0003 μg L(-1) and 1.2 μg L(-1). The relative standard deviations (RSD%) for eleven replicate determinations of 4.0 μg L(-1) HCHO were 2.2%. Furthermore, the feasibility of the developed method was investigated via the determination of HCHO concentration in environmental water and wastewater samples.

Synthesis of full Poincaré beams by means of uniaxial crystals

NASA Astrophysics Data System (ADS)

Piquero, G.; Monroy, L.; Santarsiero, M.; Alonzo, M.; de Sande, J. C. G.

2018-06-01

A simple optical system is proposed to generate full-Poincaré beams (FPBs), i.e. beams presenting all possible states of (total) polarization across their transverse section. The method consists in focusing a uniformly polarized laser beam onto a uniaxial crystal having its optic axis parallel to the propagation axis of the impinging beam. A simple approximated model is used to obtain the analytical expression of the beam polarization at the output of the crystal. The output beam is then proved to be a FPB. By changing the polarization state of the input field, full-Poincaré beams are still obtained, but presenting different distributions of the polarization state across the beam section. Experimental results are reported, showing an excellent agreement with the theoretical predictions.

Tunable, Flexible, and Efficient Optimization of Control Pulses for Practical Qubits

NASA Astrophysics Data System (ADS)

Machnes, Shai; Assémat, Elie; Tannor, David; Wilhelm, Frank K.

2018-04-01

Quantum computation places very stringent demands on gate fidelities, and experimental implementations require both the controls and the resultant dynamics to conform to hardware-specific constraints. Superconducting qubits present the additional requirement that pulses must have simple parameterizations, so they can be further calibrated in the experiment, to compensate for uncertainties in system parameters. Other quantum technologies, such as sensing, require extremely high fidelities. We present a novel, conceptually simple and easy-to-implement gradient-based optimal control technique named gradient optimization of analytic controls (GOAT), which satisfies all the above requirements, unlike previous approaches. To demonstrate GOAT's capabilities, with emphasis on flexibility and ease of subsequent calibration, we optimize fast coherence-limited pulses for two leading superconducting qubits architectures—flux-tunable transmons and fixed-frequency transmons with tunable couplers.

Non-invasive continuous imaging of drug release from soy-based skin equivalent using wide-field interferometry

NASA Astrophysics Data System (ADS)

Gabai, Haniel; Baranes-Zeevi, Maya; Zilberman, Meital; Shaked, Natan T.

2013-04-01

We propose an off-axis interferometric imaging system as a simple and unique modality for continuous, non-contact and non-invasive wide-field imaging and characterization of drug release from its polymeric device used in biomedicine. In contrast to the current gold-standard methods in this field, usually based on chromatographic and spectroscopic techniques, our method requires no user intervention during the experiment, and only one test-tube is prepared. We experimentally demonstrate imaging and characterization of drug release from soy-based protein matrix, used as skin equivalent for wound dressing with controlled anesthetic, Bupivacaine drug release. Our preliminary results demonstrate the high potential of our method as a simple and low-cost modality for wide-field imaging and characterization of drug release from drug delivery devices.

The Webcam system: a simple, automated, computer-based video system for quantitative measurement of movement in nonhuman primates.

PubMed

Togasaki, Daniel M; Hsu, Albert; Samant, Meghana; Farzan, Bijan; DeLanney, Louis E; Langston, J William; Di Monte, Donato A; Quik, Maryka

2005-06-30

Investigations using models of neurologic disease frequently involve quantifying animal motor activity. We developed a simple method for measuring motor activity using a computer-based video system (the Webcam system) consisting of an inexpensive video camera connected to a personal computer running customized software. Images of the animals are captured at half-second intervals and movement is quantified as the number of pixel changes between consecutive images. The Webcam system allows measurement of motor activity of the animals in their home cages, without devices affixed to their bodies. Webcam quantification of movement was validated by correlation with measures simultaneously obtained by two other methods: measurement of locomotion by interruption of infrared beams; and measurement of general motor activity using portable accelerometers. In untreated squirrel monkeys, correlations of Webcam and locomotor activity exceeded 0.79, and correlations with general activity counts exceeded 0.65. Webcam activity decreased after the monkeys were rendered parkinsonian by treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), but the correlations with the other measures of motor activity were maintained. Webcam activity also correlated with clinical ratings of parkinsonism. These results indicate that the Webcam system is reliable under both untreated and experimental conditions and is an excellent method for quantifying motor activity in animals.

Simulation of green roof runoff under different substrate depths and vegetation covers by coupling a simple conceptual and a physically based hydrological model.

PubMed

Soulis, Konstantinos X; Valiantzas, John D; Ntoulas, Nikolaos; Kargas, George; Nektarios, Panayiotis A

2017-09-15

In spite of the well-known green roof benefits, their widespread adoption in the management practices of urban drainage systems requires the use of adequate analytical and modelling tools. In the current study, green roof runoff modeling was accomplished by developing, testing, and jointly using a simple conceptual model and a physically based numerical simulation model utilizing HYDRUS-1D software. The use of such an approach combines the advantages of the conceptual model, namely simplicity, low computational requirements, and ability to be easily integrated in decision support tools with the capacity of the physically based simulation model to be easily transferred in conditions and locations other than those used for calibrating and validating it. The proposed approach was evaluated with an experimental dataset that included various green roof covers (either succulent plants - Sedum sediforme, or xerophytic plants - Origanum onites, or bare substrate without any vegetation) and two substrate depths (either 8 cm or 16 cm). Both the physically based and the conceptual models matched very closely the observed hydrographs. In general, the conceptual model performed better than the physically based simulation model but the overall performance of both models was sufficient in most cases as it is revealed by the Nash-Sutcliffe Efficiency index which was generally greater than 0.70. Finally, it was showcased how a physically based and a simple conceptual model can be jointly used to allow the use of the simple conceptual model for a wider set of conditions than the available experimental data and in order to support green roof design. Copyright © 2017 Elsevier Ltd. All rights reserved.

Numerical model for the thermal behavior of thermocline storage tanks

NASA Astrophysics Data System (ADS)

Ehtiwesh, Ismael A. S.; Sousa, Antonio C. M.

2018-03-01

Energy storage is a critical factor in the advancement of solar thermal power systems for the sustained delivery of electricity. In addition, the incorporation of thermal energy storage into the operation of concentrated solar power systems (CSPs) offers the potential of delivering electricity without fossil-fuel backup even during peak demand, independent of weather conditions and daylight. Despite this potential, some areas of the design and performance of thermocline systems still require further attention for future incorporation in commercial CSPs, particularly, their operation and control. Therefore, the present study aims to develop a simple but efficient numerical model to allow the comprehensive analysis of thermocline storage systems aiming better understanding of their dynamic temperature response. The validation results, despite the simplifying assumptions of the numerical model, agree well with the experiments for the time evolution of the thermocline region. Three different cases are considered to test the versatility of the numerical model; for the particular type of a storage tank with top round impingement inlet, a simple analytical model was developed to take into consideration the increased turbulence level in the mixing region. The numerical predictions for the three cases are in general good agreement against the experimental results.

Study on transient beam loading compensation for China ADS proton linac injector II

NASA Astrophysics Data System (ADS)

Gao, Zheng; He, Yuan; Wang, Xian-Wu; Chang, Wei; Zhang, Rui-Feng; Zhu, Zheng-Long; Zhang, Sheng-Hu; Chen, Qi; Powers, Tom

2016-05-01

Significant transient beam loading effects were observed during beam commissioning tests of prototype II of the injector for the accelerator driven sub-critical (ADS) system, which took place at the Institute of Modern Physics, Chinese Academy of Sciences, between October and December 2014. During these tests experiments were performed with continuous wave (CW) operation of the cavities with pulsed beam current, and the system was configured to make use of a prototype digital low level radio frequency (LLRF) controller. The system was originally operated in pulsed mode with a simple proportional plus integral and deviation (PID) feedback control algorithm, which was not able to maintain the desired gradient regulation during pulsed 10 mA beam operations. A unique simple transient beam loading compensation method which made use of a combination of proportional and integral (PI) feedback and feedforward control algorithm was implemented in order to significantly reduce the beam induced transient effect in the cavity gradients. The superconducting cavity field variation was reduced to less than 1.7% after turning on this control algorithm. The design and experimental results of this system are presented in this paper. Supported by National Natural Science Foundation of China (91426303, 11525523)

Architectural-level power estimation and experimentation

NASA Astrophysics Data System (ADS)

Ye, Wu

With the emergence of a plethora of embedded and portable applications and ever increasing integration levels, power dissipation of integrated circuits has moved to the forefront as a design constraint. Recent years have also seen a significant trend towards designs starting at the architectural (or RT) level. Those demand accurate yet fast RT level power estimation methodologies and tools. This thesis addresses issues and experiments associate with architectural level power estimation. An execution driven, cycle-accurate RT level power simulator, SimplePower, was developed using transition-sensitive energy models. It is based on the architecture of a five-stage pipelined RISC datapath for both 0.35mum and 0.8mum technology and can execute the integer subset of the instruction set of SimpleScalar . SimplePower measures the energy consumed in the datapath, memory and on-chip buses. During the development of SimplePower , a partitioning power modeling technique was proposed to model the energy consumed in complex functional units. The accuracy of this technique was validated with HSPICE simulation results for a register file and a shifter. A novel, selectively gated pipeline register optimization technique was proposed to reduce the datapath energy consumption. It uses the decoded control signals to selectively gate the data fields of the pipeline registers. Simulation results show that this technique can reduce the datapath energy consumption by 18--36% for a set of benchmarks. A low-level back-end compiler optimization, register relabeling, was applied to reduce the on-chip instruction cache data bus switch activities. Its impact was evaluated by SimplePower. Results show that it can reduce the energy consumed in the instruction data buses by 3.55--16.90%. A quantitative evaluation was conducted for the impact of six state-of-art high-level compilation techniques on both datapath and memory energy consumption. The experimental results provide a valuable insight for designers to develop future power-aware compilation frameworks for embedded systems.

Development of a proof of concept low temperature 4He Superfluid Magnetic Pump

NASA Astrophysics Data System (ADS)

Jahromi, Amir E.; Miller, Franklin K.

2017-03-01

We describe the development and experimental results of a proof of concept Superfluid Magnetic Pump in this work. This novel low temperature, no moving part pump can replace the existing bellows-piston driven 4He or 3He-4He mixture compressor/circulators used in various sub Kelvin refrigeration systems such as dilution, Superfluid pulse tube, Stirling, or active magnetic regenerative refrigerators. Due to the superior thermal transport properties of sub-Lambda 4He this pump can also be used as a simple circulator to distribute cooling over large surface areas. Our pump was experimentally shown to produce a maximum flow rate of 440 mg/s (averaged over cycle), 665 mg/s (peak) and produced a maximum pressure difference of 2323 Pa using only the more common isotope of helium, 4He. This pump worked in an ;ideal; thermodynamic state: The experimental results matched with the theoretical values predicted by a computer model. Pump curves were developed to map the performance of this pump. This successful demonstration will enable this novel pump to be implemented in suitable sub Kelvin refrigeration systems.

Kalman filter based control for Adaptive Optics

NASA Astrophysics Data System (ADS)

Petit, Cyril; Quiros-Pacheco, Fernando; Conan, Jean-Marc; Kulcsár, Caroline; Raynaud, Henri-François; Fusco, Thierry

2004-12-01

Classical Adaptive Optics suffer from a limitation of the corrected Field Of View. This drawback has lead to the development of MultiConjugated Adaptive Optics. While the first MCAO experimental set-ups are presently under construction, little attention has been paid to the control loop. This is however a key element in the optimization process especially for MCAO systems. Different approaches have been proposed in recent articles for astronomical applications : simple integrator, Optimized Modal Gain Integrator and Kalman filtering. We study here Kalman filtering which seems a very promising solution. Following the work of Brice Leroux, we focus on a frequential characterization of kalman filters, computing a transfer matrix. The result brings much information about their behaviour and allows comparisons with classical controllers. It also appears that straightforward improvements of the system models can lead to static aberrations and vibrations filtering. Simulation results are proposed and analysed thanks to our frequential characterization. Related problems such as model errors, aliasing effect reduction or experimental implementation and testing of Kalman filter control loop on a simplified MCAO experimental set-up could be then discussed.

The Limitations of Model-Based Experimental Design and Parameter Estimation in Sloppy Systems

PubMed Central

Tolman, Malachi; Thames, Howard D.; Mason, Kathy A.

2016-01-01

We explore the relationship among experimental design, parameter estimation, and systematic error in sloppy models. We show that the approximate nature of mathematical models poses challenges for experimental design in sloppy models. In many models of complex biological processes it is unknown what are the relevant physical mechanisms that must be included to explain system behaviors. As a consequence, models are often overly complex, with many practically unidentifiable parameters. Furthermore, which mechanisms are relevant/irrelevant vary among experiments. By selecting complementary experiments, experimental design may inadvertently make details that were ommitted from the model become relevant. When this occurs, the model will have a large systematic error and fail to give a good fit to the data. We use a simple hyper-model of model error to quantify a model’s discrepancy and apply it to two models of complex biological processes (EGFR signaling and DNA repair) with optimally selected experiments. We find that although parameters may be accurately estimated, the discrepancy in the model renders it less predictive than it was in the sloppy regime where systematic error is small. We introduce the concept of a sloppy system–a sequence of models of increasing complexity that become sloppy in the limit of microscopic accuracy. We explore the limits of accurate parameter estimation in sloppy systems and argue that identifying underlying mechanisms controlling system behavior is better approached by considering a hierarchy of models of varying detail rather than focusing on parameter estimation in a single model. PMID:27923060

Modelling Simple Experimental Platform for In Vitro Study of Drug Elution from Drug Eluting Stents (DES)

NASA Astrophysics Data System (ADS)

Kalachev, L. V.

2016-06-01

We present a simple model of experimental setup for in vitro study of drug release from drug eluting stents and drug propagation in artificial tissue samples representing blood vessels. The model is further reduced using the assumption on vastly different characteristic diffusion times in the stent coating and in the artificial tissue. The model is used to derive a relationship between the times at which the measurements have to be taken for two experimental platforms, with corresponding artificial tissue samples made of different materials with different drug diffusion coefficients, to properly compare the drug release characteristics of drug eluting stents.

Bell's Theorem and Einstein's "Spooky Actions" from a Simple Thought Experiment

ERIC Educational Resources Information Center

Kuttner, Fred; Rosenblum, Bruce

2010-01-01

In 1964 John Bell proved a theorem allowing the experimental test of whether what Einstein derided as "spooky actions at a distance" actually exist. We will see that they "do". Bell's theorem can be displayed with a simple, nonmathematical thought experiment suitable for a physics course at "any" level. And a simple, semi-classical derivation of…

CMOS Active-Pixel Image Sensor With Simple Floating Gates

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

1996-01-01

Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

SNMP-SI: A Network Management Tool Based on Slow Intelligence System Approach

NASA Astrophysics Data System (ADS)

Colace, Francesco; de Santo, Massimo; Ferrandino, Salvatore

The last decade has witnessed an intense spread of computer networks that has been further accelerated with the introduction of wireless networks. Simultaneously with, this growth has increased significantly the problems of network management. Especially in small companies, where there is no provision of personnel assigned to these tasks, the management of such networks is often complex and malfunctions can have significant impacts on their businesses. A possible solution is the adoption of Simple Network Management Protocol. Simple Network Management Protocol (SNMP) is a standard protocol used to exchange network management information. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP provides a tool for network administrators to manage network performance, find and solve network problems, and plan for network growth. SNMP has a big disadvantage: its simple design means that the information it deals with is neither detailed nor well organized enough to deal with the expanding modern networking requirements. Over the past years much efforts has been given to improve the lack of Simple Network Management Protocol and new frameworks has been developed: A promising approach involves the use of Ontology. This is the starting point of this paper where a novel approach to the network management based on the use of the Slow Intelligence System methodologies and Ontology based techniques is proposed. Slow Intelligence Systems is a general-purpose systems characterized by being able to improve performance over time through a process involving enumeration, propagation, adaptation, elimination and concentration. Therefore, the proposed approach aims to develop a system able to acquire, according to an SNMP standard, information from the various hosts that are in the managed networks and apply solutions in order to solve problems. To check the feasibility of this model first experimental results in a real scenario are showed.

Revisiting the Electronic Structure of FeS Monomers Using ab Initio Ligand Field Theory and the Angular Overlap Model.

PubMed

Chilkuri, Vijay Gopal; DeBeer, Serena; Neese, Frank

2017-09-05

Iron-sulfur (FeS) proteins are universally found in nature with actives sites ranging in complexity from simple monomers to multinuclear sites from two up to eight iron atoms. These sites include mononuclear (rubredoxins), dinuclear (ferredoxins and Rieske proteins), trinuclear (e.g., hydrogenases), and tetranuclear (various ferredoxins and high-potential iron-sulfur proteins). The electronic structure of the higher-nuclearity clusters is inherently extremely complex. Hence, it is reasonable to take a bottom-up approach in which clusters of increasing nuclearity are analyzed in terms of the properties of their lower nuclearity constituents. In the present study, the first step is taken by an in-depth analysis of mononuclear FeS systems. Two different FeS molecules with phenylthiolate and methylthiolate as ligands are studied in their oxidized and reduced forms using modern wave function-based ab initio methods. The ab initio electronic spectra and wave function are presented and analyzed in detail. The very intricate electronic structure-geometry relationship in these systems is analyzed using ab initio ligand field theory (AILFT) in conjunction with the angular overlap model (AOM) parametrization scheme. The simple AOM model is used to explain the effect of geometric variations on the electronic structure. Through a comparison of the ab initio computed UV-vis absorption spectra and the available experimental spectra, the low-energy part of the many-particle spectrum is carefully analyzed. We show ab initio calculated magnetic circular dichroism spectra and present a comparison with the experimental spectrum. Finally, AILFT parameters and the ab initio spectra are compared with those obtained experimentally to understand the effect of the increased covalency of the thiolate ligands on the electronic structure of FeS monomers.

Pad-mode-induced instantaneous mode instability for simple models of brake systems

NASA Astrophysics Data System (ADS)

Oberst, S.; Lai, J. C. S.

2015-10-01

Automotive disc brake squeal is fugitive, transient and remains difficult to predict. In particular, instantaneous mode squeal observed experimentally does not seem to be associated with mode coupling and its mechanism is not clear. The effects of contact pressures, friction coefficients as well as material properties (pressure and temperature dependency and anisotropy) for brake squeal propensity have not been systematically explored. By analysing a finite element model of an isotropic pad sliding on a plate similar to that of a previously reported experimental study, pad modes have been identified and found to be stable using conventional complex eigenvalue analysis. However, by subjecting the model to contact pressure harmonic excitation for a range of pressures and friction coefficients, a forced response analysis reveals that the dissipated energy for pad modes is negative and becomes more negative with increasing contact pressures and friction coefficients, indicating the potential for instabilities. The frequency of the pad mode in the sliding direction is within the range of squeal frequencies observed experimentally. Nonlinear time series analysis of the vibration velocity also confirms the evolution of instabilities induced by pad modes as the friction coefficient increases. By extending this analysis to a more realistic but simple brake model in the form of a pad-on-disc system, in-plane pad-modes, which a complex eigenvalue analysis predicts to be stable, have also been identified by negative dissipated energy for both isotropic and anisotropic pad material properties. The influence of contact pressures on potential instabilities has been found to be more dominant than changes in material properties owing to changes in pressure or temperature. Results here suggest that instantaneous mode squeal is likely caused by in-plane pad-mode instabilities.

Evidence of complex contagion of information in social media: An experiment using Twitter bots.

PubMed

Mønsted, Bjarke; Sapieżyński, Piotr; Ferrara, Emilio; Lehmann, Sune

2017-01-01

It has recently become possible to study the dynamics of information diffusion in techno-social systems at scale, due to the emergence of online platforms, such as Twitter, with millions of users. One question that systematically recurs is whether information spreads according to simple or complex dynamics: does each exposure to a piece of information have an independent probability of a user adopting it (simple contagion), or does this probability depend instead on the number of sources of exposure, increasing above some threshold (complex contagion)? Most studies to date are observational and, therefore, unable to disentangle the effects of confounding factors such as social reinforcement, homophily, limited attention, or network community structure. Here we describe a novel controlled experiment that we performed on Twitter using 'social bots' deployed to carry out coordinated attempts at spreading information. We propose two Bayesian statistical models describing simple and complex contagion dynamics, and test the competing hypotheses. We provide experimental evidence that the complex contagion model describes the observed information diffusion behavior more accurately than simple contagion. Future applications of our results include more effective defenses against malicious propaganda campaigns on social media, improved marketing and advertisement strategies, and design of effective network intervention techniques.

Deconstructing Memory in Drosophila

PubMed Central

Margulies, Carla; Tully, Tim; Dubnau, Josh

2011-01-01

Unlike most organ systems, which have evolved to maintain homeostasis, the brain has been selected to sense and adapt to environmental stimuli by constantly altering interactions in a gene network that functions within a larger neural network. This unique feature of the central nervous system provides a remarkable plasticity of behavior, but also makes experimental investigations challenging. Each experimental intervention ramifies through both gene and neural networks, resulting in unpredicted and sometimes confusing phenotypic adaptations. Experimental dissection of mechanisms underlying behavioral plasticity ultimately must accomplish an integration across many levels of biological organization, including genetic pathways acting within individual neurons, neural network interactions which feed back to gene function, and phenotypic observations at the behavioral level. This dissection will be more easily accomplished for model systems such as Drosophila, which, compared with mammals, have relatively simple and manipulable nervous systems and genomes. The evolutionary conservation of behavioral phenotype and the underlying gene function ensures that much of what we learn in such model systems will be relevant to human cognition. In this essay, we have not attempted to review the entire Drosophila memory field. Instead, we have tried to discuss particular findings that provide some level of intellectual synthesis across three levels of biological organization: behavior, neural circuitry and biochemical pathways. We have attempted to use this integrative approach to evaluate distinct mechanistic hypotheses, and to propose critical experiments that will advance this field. PMID:16139203

Playing a quantum game with a qutrit

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

Sinha, Urbasi; Kolenderski, Piotr; Youning, Li

The Aharon Vaidman (AV) quantum game [1] demonstrates the advantage of using simple quantum systems to outperform classical strategies. We present an experimental test of this quantum advantage by using a three-state quantum system (qutrit) encoded in a spatial mode of a single photon passing through a system of three slits [2,3]. We prepare its states by controlling the photon propagation and the number of open and closed slits. We perform POVM measurements by placing detectors in the positions corresponding to near and far field. These tools allow us to perform tomographic reconstructions of qutrit states and play the AVmore » game with compelling evidence of the quantum advantage.« less

Microgravity effects on electrodeposition of metals and metal-cermet mixtures

NASA Technical Reports Server (NTRS)

Maybee, George W.; Riley, Clyde; Coble, H. Dwain

1987-01-01

An experimental system, designed to investigate the potential advantages of electrodeposition in microgravity, is being developed by the McDonnell Douglas Astronautics Company-Huntsville Division and the University of Alabama in Huntsville. It is intended to fly as an Orbiter payload when NASA resumes STS operations. The system will provide power, thermal conditioning, command and control for the production of electrodeposits; system performance data will be recorded for post-flight analysis. Plated metal surfaces will be created using simple electrolytic cells with pure metal electrodes immersed in aqueous electrolytic solutions. Crystalline structure and other properties will be analyzed to identify differences between samples produced in flight and those obtained from ground-based operations.

Comparison of Hansen--Roach and ENDF/B-IV cross sections for $sup 233$U criticality calculations

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

McNeany, S. R.; Jenkins, J. D.

A comparison is made between criticality calculations performed using ENDF/B-IV cross sections and the 16-group Hansen-- Roach library at ORNL. The area investigated is homogeneous systems of highly enriched $sup 233$U in simple geometries. Calculations are compared with experimental data for a wide range of H/$sup 233$U ratios. Results show that calculations of k/sub eff/ made with the Hansen--Roach cross sections agree within 1.5 percent for the experiments considered. Results using ENDF/B-IV cross sections were in good agreement for well-thermalized systems, but discrepancies up to 7 percent in k/sub eff/ were observed in fast and epithermal systems. (auth)

Replication Strategy for Spatiotemporal Data Based on Distributed Caching System

PubMed Central

Xiong, Lian; Tao, Yang; Xu, Juan; Zhao, Lun

2018-01-01

The replica strategy in distributed cache can effectively reduce user access delay and improve system performance. However, developing a replica strategy suitable for varied application scenarios is still quite challenging, owing to differences in user access behavior and preferences. In this paper, a replication strategy for spatiotemporal data (RSSD) based on a distributed caching system is proposed. By taking advantage of the spatiotemporal locality and correlation of user access, RSSD mines high popularity and associated files from historical user access information, and then generates replicas and selects appropriate cache node for placement. Experimental results show that the RSSD algorithm is simple and efficient, and succeeds in significantly reducing user access delay. PMID:29342897

Experimental verification of multidimensional quantum steering

NASA Astrophysics Data System (ADS)

Li, Che-Ming; Lo, Hsin-Pin; Chen, Liang-Yu; Yabushita, Atsushi

2018-03-01

Quantum steering enables one party to communicate with another remote party even if the sender is untrusted. Such characteristics of quantum systems not only provide direct applications to quantum information science, but are also conceptually important for distinguishing between quantum and classical resources. While concrete illustrations of steering have been shown in several experiments, quantum steering has not been certified for higher dimensional systems. Here, we introduce a simple method to experimentally certify two different kinds of quantum steering: Einstein-Podolsky-Rosen (EPR) steering and single-system (SS) steering (i.e., temporal steering), for dimensionality (d) up to d = 16. The former reveals the steerability among bipartite systems, whereas the latter manifests itself in single quantum objects. We use multidimensional steering witnesses to verify EPR steering of polarization-entangled pairs and SS steering of single photons. The ratios between the measured witnesses and the maximum values achieved by classical mimicries are observed to increase with d for both EPR and SS steering. The designed scenario offers a new method to study further the genuine multipartite steering of large dimensionality and potential uses in quantum information processing.

Lateral-Line Detection of Underwater Objects: From Goldfish to Submarines

NASA Astrophysics Data System (ADS)

van Hemmen, J. Leo

2010-03-01

Fish and some aquatic amphibians use their mechanosensory lateral-line system to navigate by means of hydrodynamic cues. How a fish determines an object's position and shape only through the lateral-line system and the ensuing neuronal processing is still a challenging problem. Our studies have shown that both stimulus position and stimulus form can be determined within the range of about one fish length and are encoded through the response of the afferent nerves originating from the detectors. A minimal detection model of a vibrating sphere (a dipole) has now been extended to other stimuli such as translating spheres, ellipsoids, or even wakes (vortex rings). The theoretical model is fully verified by experimental data. We have also constructed an underwater robot with an artificial lateral-line system designed to detect e.g. the presence of walls by measuring the change of water flow around the body. We will show how a simple model fits experimental results obtained from trout and goldfish and how a submarine may well be able to detect underwater objects by using an artificial lateral-line system.

Minimizing irreversible losses in quantum systems by local counterdiabatic driving

PubMed Central

Sels, Dries; Polkovnikov, Anatoli

2017-01-01

Counterdiabatic driving protocols have been proposed [Demirplak M, Rice SA (2003) J Chem Phys A 107:9937–9945; Berry M (2009) J Phys A Math Theor 42:365303] as a means to make fast changes in the Hamiltonian without exciting transitions. Such driving in principle allows one to realize arbitrarily fast annealing protocols or implement fast dissipationless driving, circumventing standard adiabatic limitations requiring infinitesimally slow rates. These ideas were tested and used both experimentally and theoretically in small systems, but in larger chaotic systems, it is known that exact counterdiabatic protocols do not exist. In this work, we develop a simple variational approach allowing one to find the best possible counterdiabatic protocols given physical constraints, like locality. These protocols are easy to derive and implement both experimentally and numerically. We show that, using these approximate protocols, one can drastically suppress heating and increase fidelity of quantum annealing protocols in complex many-particle systems. In the fast limit, these protocols provide an effective dual description of adiabatic dynamics, where the coupling constant plays the role of time and the counterdiabatic term plays the role of the Hamiltonian. PMID:28461472

High speed imaging of dynamic processes with a switched source x-ray CT system

NASA Astrophysics Data System (ADS)

Thompson, William M.; Lionheart, William R. B.; Morton, Edward J.; Cunningham, Mike; Luggar, Russell D.

2015-05-01

Conventional x-ray computed tomography (CT) scanners are limited in their scanning speed by the mechanical constraints of their rotating gantries and as such do not provide the necessary temporal resolution for imaging of fast-moving dynamic processes, such as moving fluid flows. The Real Time Tomography (RTT) system is a family of fast cone beam CT scanners which instead use multiple fixed discrete sources and complete rings of detectors in an offset geometry. We demonstrate the potential of this system for use in the imaging of such high speed dynamic processes and give results using simulated and real experimental data. The unusual scanning geometry results in some challenges in image reconstruction, which are overcome using algebraic iterative reconstruction techniques and explicit regularisation. Through the use of a simple temporal regularisation term and by optimising the source firing pattern, we show that temporal resolution of the system may be increased at the expense of spatial resolution, which may be advantageous in some situations. Results are given showing temporal resolution of approximately 500 µs with simulated data and 3 ms with real experimental data.

Probing quasi-one-dimensional band structures by plasmon spectroscopy

NASA Astrophysics Data System (ADS)

Lichtenstein, T.; Mamiyev, Z.; Braun, C.; Sanna, S.; Schmidt, W. G.; Tegenkamp, C.; Pfnür, H.

2018-04-01

The plasmon dispersion is inherently related to the continuum of electron-hole pair excitations. Therefore, the comparison of this continuum, as derived from band structure calculations, with experimental data of plasmon dispersion, can yield direct information about the form of the occupied as well as the unoccupied band structure in the vicinity of the Fermi level. The relevance of this statement is illustrated by a detailed analysis of plasmon dispersions in quasi-one-dimensional systems combining experimental electron energy loss spectroscopy with quantitative density-functional theory (DFT) calculations. Si(557)-Au and Si(335)-Au with single atomic chains per terrace are compared with the Si(775)-Au system, which has a double Au chain on each terrace. We demonstrate that both hybridization between Si surface states and the Au chains as well as electronic correlations lead to increasing deviations from the nearly free electron picture that is suggested by a too simple interpretation of data of angular resolved photoemission (ARPES) of these systems, particularly for the double chain system. These deviations are consistently predicted by the DFT calculations. Thus also dimensional crossover can be explained.

Analytical and experimental study of the vibration of bonded beams with a lap joint

NASA Technical Reports Server (NTRS)

Rao, M. D.; Crocker, M. J.

1990-01-01

A theoretical model to study the flexural vibration of a bonded lap joint system is described in this paper. First, equations of motion at the joint region are derived using a differential element approach. The transverse displacements of the upper and lower beam are considered to be different. The adhesive is assumed to be linearly viscoelastic and the widely used Kelvin-Voight model is used to represent the viscoelastic behavior of the adhesive. The shear force at the interface between the adhesive and the beam is obtained from the simple bending motion equations of the two beams. The resulting equations of motion are combined with the equations of transverse vibration of the beams in the unjointed regions. These are later solved as a boundary value problem to obtain the eigenvalues and eigenvectors of the system. The model can be used to predict the natural frequencies, modal damping ratios, and mode shapes of the system for free vibration. Good agreement between numerical and experimental results was obtained for a system of graphite epoxy beams lap-jointed by an epoxy adhesive.

Development of a dual-field heteropoplar power converter

NASA Technical Reports Server (NTRS)

Eisenhaure, D. B.; Johnson, B.; Bliamptis, T.; St. George, E.

1981-01-01

The design and testing of a 400 watt, dual phase, dual rotor, field modulated inductor alternator is described. The system is designed for use as a flywheel to ac utility line or flywheel to dc bus (electric vehicle) power converter. The machine is unique in that it uses dual rotors and separately controlled fields to produce output current and voltage which are in phase with each other. Having the voltage and current in phase allows the power electronics to be made of simple low cost components. Based on analytical predictions and experimental results, development of a complete 22 kilowatt (30 Hp) power conversion system is recommended. This system would include power electronics and controls and would replace the inductor alternator with an improved electromagnetic conversion system.

Solar thermophotovoltaic system using nanostructures

DOE PAGES

Ungaro, Craig; Gray, Stephen K.; Gupta, Mool C.

2015-08-20

This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is bothmore » easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids.« less

Open quantum random walks: Bistability on pure states and ballistically induced diffusion

NASA Astrophysics Data System (ADS)

Bauer, Michel; Bernard, Denis; Tilloy, Antoine

2013-12-01

Open quantum random walks (OQRWs) deal with quantum random motions on a line for systems with internal and orbital degrees of freedom. The internal system behaves as a quantum random gyroscope coding for the direction of the orbital moves. We reveal the existence of a transition, depending on OQRW moduli, in the internal system behaviors from simple oscillations to random flips between two unstable pure states. This induces a transition in the orbital motions from the usual diffusion to ballistically induced diffusion with a large mean free path and large effective diffusion constant at large times. We also show that mixed states of the internal system are converted into random pure states during the process. We touch upon possible experimental realizations.

Control technology development

NASA Astrophysics Data System (ADS)

Schaechter, D. B.

1982-03-01

The main objectives of the control technology development task are given in the slide below. The first is to develop control design techniques based on flexible structural models, rather than simple rigid-body models. Since large space structures are distributed parameter systems, a new degree of freedom, that of sensor/actuator placement, may be exercised for improving control system performance. Another characteristic of large space structures is numerous oscillatory modes within the control bandwidth. Reduced-order controller design models must be developed which produce stable closed-loop systems when combined with the full-order system. Since the date of an actual large-space-structure flight is rapidly approaching, it is vitally important that theoretical developments are tested in actual hardware. Experimental verification is a vital counterpart of all current theoretical developments.

Back to the Basics: Cnidarians Start to Fire

PubMed Central

Bosch, Thomas C. G.; Klimovich, Alexander; Domazet-Lošo, Tomislav; Gründer, Stefan; Holstein, Thomas W.; Jékely, Gáspár; Miller, David J.; Murillo-Rincon, Andrea P.; Rentzsch, Fabian; Richards, Gemma S.; Schröder, Katja; Technau, Ulrich; Yuste, Rafael

2016-01-01

The nervous systems of cnidarians, pre-bilaterian animals that diverged close to the base of the metazoan radiation, are structurally simple and thus have great potential to inform us about basic structural and functional principles of neural circuits. Unfortunately, cnidarians have thus far been relatively intractable to electrophysiological and genetic techniques and consequently have been largely passed over by neurobiologists. However, recent advances in molecular and imaging methods are fueling a renaissance of interest in and research into cnidarians nervous systems. Here, we review current knowledge on the nervous systems of some cnidarian species and propose that researchers should seize this opportunity and undertake the study of this phylum as strategic experimental systems with great basic and translational relevance for neuroscience. PMID:28041633

Back to the Basics: Cnidarians Start to Fire.

PubMed

Bosch, Thomas C G; Klimovich, Alexander; Domazet-Lošo, Tomislav; Gründer, Stefan; Holstein, Thomas W; Jékely, Gáspár; Miller, David J; Murillo-Rincon, Andrea P; Rentzsch, Fabian; Richards, Gemma S; Schröder, Katja; Technau, Ulrich; Yuste, Rafael

2017-02-01

The nervous systems of cnidarians, pre-bilaterian animals that diverged close to the base of the metazoan radiation, are structurally simple and thus have great potential to reveal fundamental principles of neural circuits. Unfortunately, cnidarians have thus far been relatively intractable to electrophysiological and genetic techniques and consequently have been largely passed over by neurobiologists. However, recent advances in molecular and imaging methods are fueling a renaissance of interest in and research into cnidarians nervous systems. Here, we review current knowledge on the nervous systems of cnidarian species and propose that researchers should seize this opportunity and undertake the study of members of this phylum as strategic experimental systems with great basic and translational relevance for neuroscience. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling and experimental study on characterization of micromachined thermal gas inertial sensors.

PubMed

Zhu, Rong; Ding, Henggao; Su, Yan; Yang, Yongjun

2010-01-01

Micromachined thermal gas inertial sensors based on heat convection are novel devices that compared with conventional micromachined inertial sensors offer the advantages of simple structures, easy fabrication, high shock resistance and good reliability by virtue of using a gaseous medium instead of a mechanical proof mass as key moving and sensing elements. This paper presents an analytical modeling for a micromachined thermal gas gyroscope integrated with signal conditioning. A simplified spring-damping model is utilized to characterize the behavior of the sensor. The model relies on the use of the fluid mechanics and heat transfer fundamentals and is validated using experimental data obtained from a test-device and simulation. Furthermore, the nonideal issues of the sensor are addressed from both the theoretical and experimental points of view. The nonlinear behavior demonstrated in experimental measurements is analyzed based on the model. It is concluded that the sources of nonlinearity are mainly attributable to the variable stiffness of the sensor system and the structural asymmetry due to nonideal fabrication.

Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes.

PubMed

Haddock, Luis J; Kim, David Y; Mukai, Shizuo

2013-01-01

Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

A Practice-Oriented Bifurcation Analysis for Pulse Energy Converters: A Stability Margin

NASA Astrophysics Data System (ADS)

Kolokolov, Yury; Monovskaya, Anna

The popularity of systems of pulse energy conversion (PEC-systems) for practical applications is due to the heightened efficiency of energy conversion processes with comparatively simple realizations. Nevertheless, a PEC-system represents a nonlinear object with a variable structure, and the bifurcation analysis remains the basic tool to describe PEC dynamics evolution. The paper is devoted to the discussion on whether the scientific viewpoint on the natural nonlinear dynamics evolution can be involved in practical applications. We focus on the problems connected with stability boundaries of an operating regime. The results of both small-signal analysis and computational bifurcation analysis are considered in the parametrical space in comparison with the results of the experimental identification of the zonal heterogeneity of the operating process. This allows to propose an adapted stability margin as a sufficiently safe distance before the point after which the operating process begins to lose the stability. Such stability margin can extend the permissible operating domain in the parametrical space at the expense of using cause-and-effect relations in the context of natural regularities of nonlinear dynamics. Reasoning and discussion are based on the experimental and computational results for a synchronous buck converter with a pulse-width modulation. The presented results can be useful, first of all, for PEC-systems with significant variation of equivalent inductance and/or capacity. We believe that the discussion supports a viewpoint by which the contemporary methods of the computational and experimental bifurcation analyses possess both analytical abilities and experimental techniques for promising solutions which could be practice-oriented for PEC-systems.

Implementation of a cloud-based electronic medical record exchange system in compliance with the integrating healthcare enterprise's cross-enterprise document sharing integration profile.

PubMed

Wu, Chien Hua; Chiu, Ruey Kei; Yeh, Hong Mo; Wang, Da Wei

2017-11-01

In 2011, the Ministry of Health and Welfare of Taiwan established the National Electronic Medical Record Exchange Center (EEC) to permit the sharing of medical resources among hospitals. This system can presently exchange electronic medical records (EMRs) among hospitals, in the form of medical imaging reports, laboratory test reports, discharge summaries, outpatient records, and outpatient medication records. Hospitals can send or retrieve EMRs over the virtual private network by connecting to the EEC through a gateway. International standards should be adopted in the EEC to allow users with those standards to take advantage of this exchange service. In this study, a cloud-based EMR-exchange prototyping system was implemented on the basis of the Integrating the Healthcare Enterprise's Cross-Enterprise Document Sharing integration profile and the existing EMR exchange system. RESTful services were used to implement the proposed prototyping system on the Microsoft Azure cloud-computing platform. Four scenarios were created in Microsoft Azure to determine the feasibility and effectiveness of the proposed system. The experimental results demonstrated that the proposed system successfully completed EMR exchange under the four scenarios created in Microsoft Azure. Additional experiments were conducted to compare the efficiency of the EMR-exchanging mechanisms of the proposed system with those of the existing EEC system. The experimental results suggest that the proposed RESTful service approach is superior to the Simple Object Access Protocol method currently implemented in the EEC system, according to the irrespective response times under the four experimental scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.

Simple Perturbation Example for Quantum Chemistry.

ERIC Educational Resources Information Center

Goodfriend, P. L.

1985-01-01

Presents a simple example that illustrates various aspects of the Rayleigh-Schrodinger perturbation theory. The example is a particularly good one because it is straightforward and can be compared with both the exact solution and with experimental data. (JN)

A More Rigorous Quasi-Experimental Alternative to the One-Group Pretest-Posttest Design.

ERIC Educational Resources Information Center

Johnson, Craig W.

1986-01-01

A simple quasi-experimental design is described which may have utility in a variety of applied and laboratory research settings where ordinarily the one-group pretest-posttest pre-experimental design might otherwise be the procedure of choice. The design approaches the internal validity of true experimental designs while optimizing external…

The Parallel Worm Tracker: A Platform for Measuring Average Speed and Drug-Induced Paralysis in Nematodes

PubMed Central

Ramot, Daniel; Johnson, Brandon E.; Berry, Tommie L.; Carnell, Lucinda; Goodman, Miriam B.

2008-01-01

Background Caenorhabditis elegans locomotion is a simple behavior that has been widely used to dissect genetic components of behavior, synaptic transmission, and muscle function. Many of the paradigms that have been created to study C. elegans locomotion rely on qualitative experimenter observation. Here we report the implementation of an automated tracking system developed to quantify the locomotion of multiple individual worms in parallel. Methodology/Principal Findings Our tracking system generates a consistent measurement of locomotion that allows direct comparison of results across experiments and experimenters and provides a standard method to share data between laboratories. The tracker utilizes a video camera attached to a zoom lens and a software package implemented in MATLAB®. We demonstrate several proof-of-principle applications for the tracker including measuring speed in the absence and presence of food and in the presence of serotonin. We further use the tracker to automatically quantify the time course of paralysis of worms exposed to aldicarb and levamisole and show that tracker performance compares favorably to data generated using a hand-scored metric. Conclusions/Signficance Although this is not the first automated tracking system developed to measure C. elegans locomotion, our tracking software package is freely available and provides a simple interface that includes tools for rapid data collection and analysis. By contrast with other tools, it is not dependent on a specific set of hardware. We propose that the tracker may be used for a broad range of additional worm locomotion applications including genetic and chemical screening. PMID:18493300

A bubble column evaporator with basic flat-plate condenser for brackish and seawater desalination.

PubMed

Schmack, Mario; Ho, Goen; Anda, Martin

2016-01-01

This paper describes the development and experimental evaluation of a novel bubble column-based humidification-dehumidification system, for small-scale desalination of saline groundwater or seawater in remote regions. A bubble evaporator prototype was built and matched with a simple flat-plate type condenser for concept assessment. Consistent bubble evaporation rates of between 80 and 88 ml per hour were demonstrated. Particular focus was on the performance of the simple condenser prototype, manufactured from rectangular polyvinylchlorid plastic pipe and copper sheet, a material with a high thermal conductivity that quickly allows for conduction of the heat energy. Under laboratory conditions, a long narrow condenser model of 1500 mm length and 100 mm width achieved condensate recovery rates of around 73%, without the need for external cooling. The condenser prototype was assessed under a range of different physical conditions, that is, external water cooling, partial insulation and aspects of air circulation, via implementing an internal honeycomb screen structure. Estimated by extrapolation, an up-scaled bubble desalination system with a 1 m2 condenser may produce around 19 l of distilled water per day. Sodium chloride salt removal was found to be highly effective with condensate salt concentrations between 70 and 135 µS. Based on findings and with the intent to reduce material cost of the system, a shorter condenser length of 750 mm for the non-cooled (passive) condenser and of 500 mm for the water-cooled condenser was considered to be equally efficient as the experimentally evaluated prototype of 1500 mm length.

Optimal concentrations in transport systems

PubMed Central

Jensen, Kaare H.; Kim, Wonjung; Holbrook, N. Michele; Bush, John W. M.

2013-01-01

Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt∼2αμ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow. PMID:23594815

Modeling and analysis of a resonant nanosystem

NASA Astrophysics Data System (ADS)

Calvert, Scott L.

The majority of investigations into nanoelectromechanical resonators focus on a single area of the resonator's function. This focus varies from the development of a model for a beam's vibration, to the modeling of electrostatic forces, to a qualitative explanation of experimentally-obtained currents. Despite these efforts, there remains a gap between these works, and the level of sophistication needed to truly design nanoresonant systems for efficient commercial use. Towards this end, a comprehensive system model for both a nanobeam resonator and its related experimental setup is proposed. Furthermore, a simulation arrangement is suggested as a method for facilitating the study of the system-level behavior of these devices in a variety of cases that could not be easily obtained experimentally or analytically. The dynamics driving the nanoresonator's motion, as well as the electrical interactions influencing the forcing and output of the system, are modeled, experimentally validated, and studied. The model seeks to develop both a simple circuit representation of the nanoresonator, and to create a mathematical system that can be used to predict and interpret the observed behavior. Due to the assumptions used to simplify the model to a point of reasonable comprehension, the model is most accurate for small beam deflections near the first eigenmode of the beam. The process and results of an experimental investigation are documented, and compared with a circuit simulation modeling the full test system. The comparison qualitatively proves the functionality of the model, while a numerical analysis serves to validate the functionality and setup of the circuit simulation. The use of the simulation enables a much broader investigation of both the electrical behavior and the physical device's dynamics. It is used to complement an assessment of the tuning behavior of the system's linear natural frequency by demonstrating the tuning behavior of the full nonlinear response. The simulation is used to demonstrate the difficulties with the contemporary mixing approach to experimental data collection and to complete a variety of case studies investigating the use of the nanoresonator systems in practical applications, such as signal filtering. Many of these case studies would be difficult to complete analytically, but results are quickly achieved through the use of the simulation.

Detonation product EOS studies: Using ISLS to refine CHEETAH

NASA Astrophysics Data System (ADS)

Zaug, Joseph; Fried, Larry; Hansen, Donald

2001-06-01

Knowledge of an effective interatomic potential function underlies any effort to predict or rationalize the properties of solids and liquids. The experiments we undertake are directed towards determination of equilibrium and dynamic properties of simple fluids at densities sufficiently high that traditional computational methods and semi-empirical forms successful at ambient conditions may require reconsideration. In this paper we present high-pressure and temperature experimental sound speed data on a suite of non-ideal simple fluids and fluid mixtures. Impulsive Stimulated Light Scattering conducted in the diamond-anvil cell offers an experimental approach to determine cross-pair potential interactions through equation of state determinations. In addition the kinetics of structural relaxation in fluids can be studied. We compare our experimental results with our thermochemical computational model CHEETAH. Computational models are systematically improved with each addition of experimental data. Experimentally grounded computational models provide a good basis to confidently understand the chemical nature of reactions at extreme conditions.

A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification

PubMed Central

Choi, Dongwhi; Lee, Donghyeon; Sung Kim, Dong

2015-01-01

In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two–phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid–liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability. PMID:26462437

A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification.

PubMed

Choi, Dongwhi; Lee, Donghyeon; Kim, Dong Sung

2015-10-14

In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

Compiler-aided systematic construction of large-scale DNA strand displacement circuits using unpurified components

NASA Astrophysics Data System (ADS)

Thubagere, Anupama J.; Thachuk, Chris; Berleant, Joseph; Johnson, Robert F.; Ardelean, Diana A.; Cherry, Kevin M.; Qian, Lulu

2017-02-01

Biochemical circuits made of rationally designed DNA molecules are proofs of concept for embedding control within complex molecular environments. They hold promise for transforming the current technologies in chemistry, biology, medicine and material science by introducing programmable and responsive behaviour to diverse molecular systems. As the transformative power of a technology depends on its accessibility, two main challenges are an automated design process and simple experimental procedures. Here we demonstrate the use of circuit design software, combined with the use of unpurified strands and simplified experimental procedures, for creating a complex DNA strand displacement circuit that consists of 78 distinct species. We develop a systematic procedure for overcoming the challenges involved in using unpurified DNA strands. We also develop a model that takes synthesis errors into consideration and semi-quantitatively reproduces the experimental data. Our methods now enable even novice researchers to successfully design and construct complex DNA strand displacement circuits.

Caveats and considerations for performing pancreas-specific gene manipulations in the mouse.

PubMed

Magnuson, M A; Burlison, J S

2007-11-01

Conditional gene targeting using the Cre/loxP strategy has proven to be very useful for studies of glucose homeostasis, tissue function and dysfunction in diabetes, and pancreas development. However, use of this strategy over the past decade has revealed a variety of experimental caveats, many of which are a direct consequence of the procedures used to generate Cre-driver lines. We discuss frequently encountered experimental artefacts, the advantages of using bacterial artificial chromosome-derived transgenes or performing a Cre knockin for improving the specificity of expression, and systems for regulating Cre activity. In addition, recent studies indicate that high amounts of Cre in the pancreatic beta-cell may cause glucose intolerance and impaired insulin secretion. However, these findings, while serving as a reminder for simple experimental controls, are unlikely to diminish utilization of this very powerful and useful technology.

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

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

Warwick, J.; Dzelzainis, T.; Dieckmann, M. E.

Here, we report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥ 1T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of ε B ≈ 10 -3 is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma formore » thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.« less

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

DOE PAGES

Warwick, J.; Dzelzainis, T.; Dieckmann, M. E.; ...

2017-11-03

Here, we report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥ 1T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of ε B ≈ 10 -3 is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma formore » thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.« less

Computational models of the Posner simple and choice reaction time tasks

PubMed Central

Feher da Silva, Carolina; Baldo, Marcus V. C.

2015-01-01

The landmark experiments by Posner in the late 1970s have shown that reaction time (RT) is faster when the stimulus appears in an expected location, as indicated by a cue; since then, the so-called Posner task has been considered a “gold standard” test of spatial attention. It is thus fundamental to understand the neural mechanisms involved in performing it. To this end, we have developed a Bayesian detection system and small integrate-and-fire neural networks, which modeled sensory and motor circuits, respectively, and optimized them to perform the Posner task under different cue type proportions and noise levels. In doing so, main findings of experimental research on RT were replicated: the relative frequency effect, suboptimal RTs and significant error rates due to noise and invalid cues, slower RT for choice RT tasks than for simple RT tasks, fastest RTs for valid cues and slowest RTs for invalid cues. Analysis of the optimized systems revealed that the employed mechanisms were consistent with related findings in neurophysiology. Our models predict that (1) the results of a Posner task may be affected by the relative frequency of valid and neutral trials, (2) in simple RT tasks, input from multiple locations are added together to compose a stronger signal, and (3) the cue affects motor circuits more strongly in choice RT tasks than in simple RT tasks. In discussing the computational demands of the Posner task, attention has often been described as a filter that protects the nervous system, whose capacity is limited, from information overload. Our models, however, reveal that the main problems that must be overcome to perform the Posner task effectively are distinguishing signal from external noise and selecting the appropriate response in the presence of internal noise. PMID:26190997

Colloidal membranes: The rich confluence of geometry and liquid crystals

NASA Astrophysics Data System (ADS)

Kaplan, Cihan Nadir

A simple and experimentally realizable model system of chiral symmetry breaking is liquid-crystalline monolayers of aligned, identical hard rods. In these materials, tuning the chirality at the molecular level affects the geometry at systems level, thereby inducing a myriad of morphological transitions. This thesis presents theoretical studies motivated by the rich phenomenology of these colloidal monolayers. High molecular chirality leads to assemblages of rods exhibiting macroscopic handedness. In the first part we consider one such geometry, twisted ribbons, which are minimal surfaces to a double helix. By employing a theoretical approach that combines liquid-crystalline order with the preferred shape, we focus on the phase transition from simple flat monolayers to these twisted structures. In these monolayers, regions of broken chiral symmetry nucleate at the interfaces, as in a chiral smectic A sample. The second part particularly focuses on the detailed structure and thermodynamic stability of two types of observed interfaces, the monolayer edge and domain walls in simple flat monolayers. Both the edge and "twist-walls" are quasi-one-dimensional bands of molecular twist deformations dictated by local chiral interactions and surface energy considerations. We develop a unified theory of these interfaces by utilizing the de Gennes framework accompanied by appropriate surface energy terms. The last part turns to colloidal "cookies", which form in mixtures of rods with opposite handedness. These elegant structures are essentially flat monolayers surrounded by an array of local, three dimensional cusp defects. We reveal the thermodynamic and structural characteristics of cookies. Furthermore, cookies provide us with a simple relation to determine the intrinsic curvature modulus of our model system, an important constant associated with topological properties of membranes. Our results may have impacts on a broader class of soft thin films.

Modeling of electron behaviors under microwave electric field in methane and air pre-mixture gas plasma assisted combustion

NASA Astrophysics Data System (ADS)

Akashi, Haruaki; Sasaki, K.; Yoshinaga, T.

2011-10-01

Recently, plasma-assisted combustion has been focused on for achieving more efficient combustion way of fossil fuels, reducing pollutants and so on. Shinohara et al has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power without increase of gas temperature. This suggests that electrons heated by microwave electric field assist the combustion. They also measured emission from 2nd Positive Band System (2nd PBS) of nitrogen during the irradiation. To clarify this mechanism, electron behavior under microwave power should be examined. To obtain electron transport parameters, electron Monte Carlo simulations in methane and air mixture gas have been done. A simple model has been developed to simulate inside the flame. To make this model simple, some assumptions are made. The electrons diffuse from the combustion plasma region. And the electrons quickly reach their equilibrium state. And it is found that the simulated emission from 2nd PBS agrees with the experimental result. Recently, plasma-assisted combustion has been focused on for achieving more efficient combustion way of fossil fuels, reducing pollutants and so on. Shinohara et al has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power without increase of gas temperature. This suggests that electrons heated by microwave electric field assist the combustion. They also measured emission from 2nd Positive Band System (2nd PBS) of nitrogen during the irradiation. To clarify this mechanism, electron behavior under microwave power should be examined. To obtain electron transport parameters, electron Monte Carlo simulations in methane and air mixture gas have been done. A simple model has been developed to simulate inside the flame. To make this model simple, some assumptions are made. The electrons diffuse from the combustion plasma region. And the electrons quickly reach their equilibrium state. And it is found that the simulated emission from 2nd PBS agrees with the experimental result. This work was supported by KAKENHI (22340170).

A simple pendulum-based measurement of g with a smartphone light sensor

NASA Astrophysics Data System (ADS)

Pili, Unofre; Violanda, Renante

2018-07-01

A quick and very accessible method for the measurement of acceleration due to gravity is presented. The experimental set-up employs a smartphone ambient light sensor as the motion timer for measuring the period of a simple pendulum. This allowed us to obtain an experimental value, 9.72  +  0.05 m s‑2, for the gravitational acceleration which is in good agreement with the local theoretical value of 9.78 m s‑2.

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

Liu, Xiaoming; Lan, Chuwen; Li, Bo

We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

Synchronizing movements with the metronome: nonlinear error correction and unstable periodic orbits.

PubMed

Engbert, Ralf; Krampe, Ralf Th; Kurths, Jürgen; Kliegl, Reinhold

2002-02-01

The control of human hand movements is investigated in a simple synchronization task. We propose and analyze a stochastic model based on nonlinear error correction; a mechanism which implies the existence of unstable periodic orbits. This prediction is tested in an experiment with human subjects. We find that our experimental data are in good agreement with numerical simulations of our theoretical model. These results suggest that feedback control of the human motor systems shows nonlinear behavior. Copyright 2001 Elsevier Science (USA).

Time dependence of breakdown in a global fiber-bundle model with continuous damage.

PubMed

Moral, L; Moreno, Y; Gómez, J B; Pacheco, A F

2001-06-01

A time-dependent global fiber-bundle model of fracture with continuous damage is formulated in terms of a set of coupled nonlinear differential equations. A first integral of this set is analytically obtained. The time evolution of the system is studied by applying a discrete probabilistic method. Several results are discussed emphasizing their differences with the standard time-dependent model. The results obtained show that with this simple model a variety of experimental observations can be qualitatively reproduced.

Defining the Fresnel zone for broadband radiation.

PubMed

Pearce, Jeremy; Mittleman, Daniel

2002-11-01

The concept of the Fresnel zone is central to many areas of imaging. In tomographic imaging, the transverse spatial resolution can be limited by the size of the first Fresnel zone, usually defined only for monochromatic radiation. With the increasing prevalence of broadband tomographic imaging systems, a generalization of this concept is required. Here, a proposed generalization is described in the context of femtosecond optics, and experimentally verified using terahertz time-domain spectroscopy. Based on this definition, a simple zone plate design is demonstrated.

Dynamic characteristics of a vibrating beam with periodic variation in bending stiffness

NASA Technical Reports Server (NTRS)

Townsend, John S.

1987-01-01

A detailed dynamic analysis is performed of a vibrating beam with bending stiffness periodic in the spatial coordinate. Using a perturbation expansion technique the free vibration solution is obtained in a closed-form, and the effects of system parameters on beam response are explored. It is found that periodic stiffness acts to modulate the modal displacements from the characteristic shape of a simple sine wave. The results are verified by a finite element solution and through experimental testing.

Vector systems for prenatal gene therapy: principles of retrovirus vector design and production.

PubMed

Howe, Steven J; Chandrashekran, Anil

2012-01-01

Vectors derived from the Retroviridae family have several attributes required for successful gene delivery. Retroviral vectors have an adequate payload size for the coding regions of most genes; they are safe to handle and simple to produce. These vectors can be manipulated to target different cell types with low immunogenicity and can permanently insert genetic information into the host cells' genome. Retroviral vectors have been used in gene therapy clinical trials and successfully applied experimentally in vitro, in vivo, and in utero.

Large area ion beam sputtered YBa2Cu3O(7-delta) films for novel device structures

NASA Astrophysics Data System (ADS)

Gauzzi, A.; Lucia, M. L.; Kellett, B. J.; James, J. H.; Pavuna, D.

1992-03-01

A simple single-target ion-beam system is employed to manufacture large areas of uniformly superconducting YBa2Cu3O(7-delta) films which can be reproduced. The required '123' stoichiometry is transferred from the target to the substrate when ion-beam power, target/ion-beam angle, and target temperature are adequately controlled. Ion-beam sputtering is experimentally demonstrated to be an effective technique for producing homogeneous YBa2Cu3O(7-delta) films.

Positive position control of robotic manipulators

NASA Technical Reports Server (NTRS)

Baz, A.; Gumusel, L.

1989-01-01

The present, simple and accurate position-control algorithm, which is applicable to fast-moving and lightly damped robot arms, is based on the positive position feedback (PPF) strategy and relies solely on position sensors to monitor joint angles of robotic arms to furnish stable position control. The optimized tuned filters, in the form of a set of difference equations, manipulate position signals for robotic system performance. Attention is given to comparisons between this PPF-algorithm controller's experimentally ascertained performance characteristics and those of a conventional proportional controller.

Peroxisystem: harnessing systems cell biology to study peroxisomes.

PubMed

Schuldiner, Maya; Zalckvar, Einat

2015-04-01

In recent years, high-throughput experimentation with quantitative analysis and modelling of cells, recently dubbed systems cell biology, has been harnessed to study the organisation and dynamics of simple biological systems. Here, we suggest that the peroxisome, a fascinating dynamic organelle, can be used as a good candidate for studying a complete biological system. We discuss several aspects of peroxisomes that can be studied using high-throughput systematic approaches and be integrated into a predictive model. Such approaches can be used in the future to study and understand how a more complex biological system, like a cell and maybe even ultimately a whole organism, works. © 2015 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

A low cost indoor localization system for mobile robot experimental setup

NASA Astrophysics Data System (ADS)

Adinandra, S.; Syarif, A.

2018-04-01

Indoor localization becomes one of the most important part in mobile robot system One fundamental requirement is to provide an easy-to-use and practical localization system for real-time experiments. In this paper we propose a combination of a recent open source virtual reality (VR) tools, a simple MATLAB code and a low cost USB webcam as an indoor mobile robot localization system Using the VR tools as a server and MATLAB as a client, the proposed solution can cover up to 1.6 [m] × 3.2 [m] with the measurement position accuracy up to 1.2 [cm]. The system is insensitive to light, easy to move and can be quickly set up. A series of successful real-time experiments with three different mobile robot types has been conducted.

Robust Multilayer Insulation for Cryogenic Systems

NASA Technical Reports Server (NTRS)

Fesmire, J. E.; Scholtens, B. F.; Augustynowicz, S. D.

2007-01-01

New requirements for thermal insulation include robust Multilayer insulation (MU) systems that work for a range of environments from high vacuum to no vacuum. Improved MLI systems must be simple to install and maintain while meeting the life-cycle cost and thermal performance objectives. Performance of actual MLI systems has been previously shown to be much worse than ideal MLI. Spacecraft that must contain cryogens for both lunar service (high vacuum) and ground launch operations (no vacuum) are planned. Future cryogenic spacecraft for the soft vacuum environment of Mars are also envisioned. Industry products using robust MLI can benefit from improved cost-efficiency and system safety. Novel materials have been developed to operate as excellent thermal insulators at vacuum levels that are much less stringent than the absolute high vacuum requirement of current MLI systems. One such robust system, Layered Composite Insulation (LCI), has been developed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. The experimental testing and development of LCI is the focus of this paper. LCI thermal performance under cryogenic conditions is shown to be six times better than MLI at soft vacuum and similar to MLI at high vacuum. The experimental apparent thermal conductivity (k-value) and heat flux data for LCI systems are compared with other MLI systems.

Spin glass model for cell reprogramming

NASA Astrophysics Data System (ADS)

Pusuluri, Sai Teja; Castillo, Horacio E.

2014-03-01

Recent experiments show that differentiated cells can be reprogrammed to become pluripotent stem cells. The possible cell fates can be modeled as attractors in a dynamical system, the ``epigenetic landscape.'' Both cellular differentiation and reprogramming can be described in the landscape picture as motion from one attractor state to another attractor state. We use a simple model based on spin glass theory that can construct a simulated epigenetic landscape starting from the experimental genomic data. We modify the model to incorporate experimental reprogramming protocols. Our simulations successfully reproduce several reprogramming experiments. We probe the robustness of the results against random changes in the model, explore the importance of asymmetric interactions between transcription factors and study the importance of histone modification errors in reprogramming.

Onset conditions for gas phase reaction and nucleation in the CVD of transition metal oxides

NASA Technical Reports Server (NTRS)

Collins, J.; Rosner, D. E.; Castillo, J.

1992-01-01

A combined experimental/theoretical study is presented of the onset conditions for gas phase reaction and particle nucleation in hot substrate/cold gas CVD of transition metal oxides. Homogeneous reaction onset conditions are predicted using a simple high activation energy reacting gas film theory. Experimental tests of the basic theory are underway using an axisymmetric impinging jet CVD reactor. No vapor phase ignition has yet been observed in the TiCl4/O2 system under accessible operating conditions (below substrate temperature Tw = 1700 K). The goal of this research is to provide CVD reactor design and operation guidelines for achieving acceptable deposit microstructures at the maximum deposition rate while simultaneously avoiding homogeneous reaction/nucleation and diffusional limitations.

Optimization of control gain by operator adjustment

NASA Technical Reports Server (NTRS)

Kruse, W.; Rothbauer, G.

1973-01-01

An optimal gain was established by measuring errors at 5 discrete control gain settings in an experimental set-up consisting of a 2-dimensional, first-order pursuit tracking task performed by subjects (S's). No significant experience effect on optimum gain setting was found in the first experiment. During the second experiment, in which control gain was continuously adjustable, high experienced S's tended to reach the previously determined optimum gain quite accurately and quickly. Less experienced S's tended to select a marginally optimum gain either below or above the experimentally determined optimum depending on initial control gain setting, although mean settings of both groups were equal. This quick and simple method is recommended for selecting control gains for different control systems and forcing functions.

Guiding of laser pulses in plasma waveguides created by linearly-polarized femtosecond laser pulses

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

Lemos, N.; Cardoso, L.; Geada, J.

We experimentally demonstrate that plasma waveguides produced with ultra-short laser pulses (sub-picosecond) in gas jets are capable of guiding high intensity laser pulses. This scheme has the unique ability of guiding a high-intensity laser pulse in a plasma waveguide created by the same laser system in the very simple and stable experimental setup. A hot plasma column was created by a femtosecond class laser that expands into an on-axis parabolic low density profile suitable to act as a waveguide for high intensity laser beams. We have successfully guided ~10 15 W cm -2 laser pulses in a 8 mm longmore » hydrogen plasma waveguide with a 35% guiding efficiency.« less

3-D imaging of large scale buried structure by 1-D inversion of very early time electromagnetic (VETEM) data

USGS Publications Warehouse

Aydmer, A.A.; Chew, W.C.; Cui, T.J.; Wright, D.L.; Smith, D.V.; Abraham, J.D.

2001-01-01

A simple and efficient method for large scale three-dimensional (3-D) subsurface imaging of inhomogeneous background is presented. One-dimensional (1-D) multifrequency distorted Born iterative method (DBIM) is employed in the inversion. Simulation results utilizing synthetic scattering data are given. Calibration of the very early time electromagnetic (VETEM) experimental waveforms is detailed along with major problems encountered in practice and their solutions. This discussion is followed by the results of a large scale application of the method to the experimental data provided by the VETEM system of the U.S. Geological Survey. The method is shown to have a computational complexity that is promising for on-site inversion.

Guiding of laser pulses in plasma waveguides created by linearly-polarized femtosecond laser pulses

DOE PAGES

Lemos, N.; Cardoso, L.; Geada, J.; ...

2018-02-16

We experimentally demonstrate that plasma waveguides produced with ultra-short laser pulses (sub-picosecond) in gas jets are capable of guiding high intensity laser pulses. This scheme has the unique ability of guiding a high-intensity laser pulse in a plasma waveguide created by the same laser system in the very simple and stable experimental setup. A hot plasma column was created by a femtosecond class laser that expands into an on-axis parabolic low density profile suitable to act as a waveguide for high intensity laser beams. We have successfully guided ~10 15 W cm -2 laser pulses in a 8 mm longmore » hydrogen plasma waveguide with a 35% guiding efficiency.« less

Effect of the Four-Step Learning Cycle Model on Students' Understanding of Concepts Related to Simple Harmonic Motion

ERIC Educational Resources Information Center

Madu, B. C.

2012-01-01

The study explored the efficacy of four-step (4-E) learning cycle approach on students understanding of concepts related to Simple Harmonic Motion (SHM). 124 students (63 for experimental group and 61 for control group) participated in the study. The students' views and ideas in simple Harmonic Achievement test were analyzed qualitatively. The…

A simple predistortion technique for suppression of nonlinear effects in periodic signals generated by nonlinear transducers

NASA Astrophysics Data System (ADS)

Novak, A.; Simon, L.; Lotton, P.

2018-04-01

Mechanical transducers, such as shakers, loudspeakers and compression drivers that are used as excitation devices to excite acoustical or mechanical nonlinear systems under test are imperfect. Due to their nonlinear behaviour, unwanted contributions appear at their output besides the wanted part of the signal. Since these devices are used to study nonlinear systems, it should be required to measure properly the systems under test by overcoming the influence of the nonlinear excitation device. In this paper, a simple method that corrects distorted output signal of the excitation device by means of predistortion of its input signal is presented. A periodic signal is applied to the input of the excitation device and, from analysing the output signal of the device, the input signal is modified in such a way that the undesirable spectral components in the output of the excitation device are cancelled out after few iterations of real-time processing. The experimental results provided on an electrodynamic shaker show that the spectral purity of the generated acceleration output approaches 100 dB after few iterations (1 s). This output signal, applied to the system under test, is thus cleaned from the undesirable components produced by the excitation device; this is an important condition to ensure a correct measurement of the nonlinear system under test.

Noise induced chaos in optically driven colloidal rings.

NASA Astrophysics Data System (ADS)

Roichman, Yael; Zaslavsky, George; Grier, David G.

2007-03-01

Given a constant flux of energy, many driven dissipative systems rapidly organize themselves into configurations that support steady state motion. Examples include swarming of bacterial colonies, convection in shaken sandpiles, and synchronization in flowing traffic. How simple objects interacting in simple ways self-organize generally is not understood, mainly because so few of the available experimental systems afford the necessary access to their microscopic degrees of freedom. This talk introduces a new class of model driven dissipative systems typified by three colloidal spheres circulating around a ring-like optical trap known as an optical vortex. By controlling the interplay between hydrodynamic interactions and fixed disorder we are able to drive a transition from a previously predicted periodic steady state to fully developed chaos. In addition, by tracking both microscopic trajectories and macroscopic collective fluctuations the relation between the onset of microscopic weak chaos and the evolution of space-time self-similarity in macroscopic transport properties is revealed. In a broader scope, several optical vortices can be coupled to create a large dissipative system where each building block has internal degrees of freedom. In such systems the little understood dynamics of processes like frustration and jamming, fluctuation-dissipation relations and the propagation of collective motion can be tracked microscopically.

A Simple Experimental Demonstration of Microbial Growth and Interaction.

ERIC Educational Resources Information Center

Wainwright, Milton

1988-01-01

Described is a simple, safe, and inexpensive experiment which allows secondary school pupils to observe how fungi and bacteria grow and interact with each other. Included are discussions of materials, methods, observations, and a historical comment. (Author/CW)

Technical Note: A simple method for air-sea gas exchange measurements in mesocosms and its application in carbon budgeting

NASA Astrophysics Data System (ADS)

Czerny, J.; Schulz, K. G.; Ludwig, A.; Riebesell, U.

2013-03-01

Mesocosms as large experimental units provide the opportunity to perform elemental mass balance calculations, e.g. to derive net biological turnover rates. However, the system is in most cases not closed at the water surface and gases exchange with the atmosphere. Previous attempts to budget carbon pools in mesocosms relied on educated guesses concerning the exchange of CO2 with the atmosphere. Here, we present a simple method for precise determination of air-sea gas exchange in mesocosms using N2O as a deliberate tracer. Beside the application for carbon budgeting, transfer velocities can be used to calculate exchange rates of any gas of known concentration, e.g. to calculate aquatic production rates of climate relevant trace gases. Using an arctic KOSMOS (Kiel Off Shore Mesocosms for future Ocean Simulation) experiment as an exemplary dataset, it is shown that the presented method improves accuracy of carbon budget estimates substantially. Methodology of manipulation, measurement, data processing and conversion to CO2 fluxes are explained. A theoretical discussion of prerequisites for precise gas exchange measurements provides a guideline for the applicability of the method under various experimental conditions.

An experimental investigation of the early dynamic impact behaviour of textile armour systems: Decoupling material from system response

NASA Astrophysics Data System (ADS)

Cepus, Elvis

This work focuses on the early impact response of textile armour systems. A relatively new data acquisition system, the Enhanced Laser Velocity Sensor (ELVS), was refined and used to generate a large database of results for a 5.57 mm diameter, 3 gram, non-deforming projectile impacting single-ply configurations of Ballistic Nylon, two weaves of Kevlar 129, and Zylon (PBO) over a range of velocities from 61 m/s to 248 m/s. In addition, one Kevlar 129 material was tested in configurations of 2, 3, 4, 8 and 16 plies over a range of strike velocities from 90 m/s to 481 m/s. ELVS results consisted of high-resolution timehistories of displacement, velocity and energy for each system tested. The strain wave velocity and ballistic performance of each system was also determined. Results taken from during the impact event were analysed up to just prior to the strain-wave rebounding from the boundary and returning to the impact point---effectively removing boundary influences. Regardless of system type, a constant rate of energy absorption within the pre-rebound timeframe was found to exist, which scales with the strike velocity to approximately the 8/3-power. Well-established single fibre theory was modified and applied to woven materials. It was assumed that three primary energy absorption mechanisms exist; elastic strain, in-plane kinetic and out-of-plane kinetic. This simple model yields the experimentally observed 8/3 exponent and parametrically predicts the difference between the different single-ply material systems, but underpredicts the observed behaviour by a factor of 2 and cannot address the performance reduction with increasing ply count. This combined experimental and analytical work confirms the long-held assumption that single fibre wave physics is applicable to multi-ply woven systems. More significantly, for the first time, it decouples material response from overall system response and provides the experimental tools and methodology required to analyse textile armour systems in a scientific manner.

Verification of RELAP5-3D code in natural circulation loop as function of the initial water inventory

NASA Astrophysics Data System (ADS)

Bertani, C.; Falcone, N.; Bersano, A.; Caramello, M.; Matsushita, T.; De Salve, M.; Panella, B.

2017-11-01

High safety and reliability of advanced nuclear reactors, Generation IV and Small Modular Reactors (SMR), have a crucial role in the acceptance of these new plants design. Among all the possible safety systems, particular efforts are dedicated to the study of passive systems because they rely on simple physical principles like natural circulation, without the need of external energy source to operate. Taking inspiration from the second Decay Heat Removal system (DHR2) of ALFRED, the European Generation IV demonstrator of the fast lead cooled reactor, an experimental facility has been built at the Energy Department of Politecnico di Torino (PROPHET facility) to study single and two-phase flow natural circulation. The facility behavior is simulated using the thermal-hydraulic system code RELAP5-3D, which is widely used in nuclear applications. In this paper, the effect of the initial water inventory on natural circulation is analyzed. The experimental time behaviors of temperatures and pressures are analyzed. The experimental matrix ranges between 69 % and 93%; the influence of the opposite effects related to the increase of the volume available for the expansion and the pressure raise due to phase change is discussed. Simulations of the experimental tests are carried out by using a 1D model at constant heat power and fixed liquid and air mass; the code predictions are compared with experimental results. Two typical responses are observed: subcooled or two phase saturated circulation. The steady state pressure is a strong function of liquid and air mass inventory. The numerical results show that, at low initial liquid mass inventory, the natural circulation is not stable but pulsated.

Genome Scale Modeling in Systems Biology: Algorithms and Resources

PubMed Central

Najafi, Ali; Bidkhori, Gholamreza; Bozorgmehr, Joseph H.; Koch, Ina; Masoudi-Nejad, Ali

2014-01-01

In recent years, in silico studies and trial simulations have complemented experimental procedures. A model is a description of a system, and a system is any collection of interrelated objects; an object, moreover, is some elemental unit upon which observations can be made but whose internal structure either does not exist or is ignored. Therefore, any network analysis approach is critical for successful quantitative modeling of biological systems. This review highlights some of most popular and important modeling algorithms, tools, and emerging standards for representing, simulating and analyzing cellular networks in five sections. Also, we try to show these concepts by means of simple example and proper images and graphs. Overall, systems biology aims for a holistic description and understanding of biological processes by an integration of analytical experimental approaches along with synthetic computational models. In fact, biological networks have been developed as a platform for integrating information from high to low-throughput experiments for the analysis of biological systems. We provide an overview of all processes used in modeling and simulating biological networks in such a way that they can become easily understandable for researchers with both biological and mathematical backgrounds. Consequently, given the complexity of generated experimental data and cellular networks, it is no surprise that researchers have turned to computer simulation and the development of more theory-based approaches to augment and assist in the development of a fully quantitative understanding of cellular dynamics. PMID:24822031

Population-reaction model and microbial experimental ecosystems for understanding hierarchical dynamics of ecosystems.

PubMed

Hosoda, Kazufumi; Tsuda, Soichiro; Kadowaki, Kohmei; Nakamura, Yutaka; Nakano, Tadashi; Ishii, Kojiro

2016-02-01

Understanding ecosystem dynamics is crucial as contemporary human societies face ecosystem degradation. One of the challenges that needs to be recognized is the complex hierarchical dynamics. Conventional dynamic models in ecology often represent only the population level and have yet to include the dynamics of the sub-organism level, which makes an ecosystem a complex adaptive system that shows characteristic behaviors such as resilience and regime shifts. The neglect of the sub-organism level in the conventional dynamic models would be because integrating multiple hierarchical levels makes the models unnecessarily complex unless supporting experimental data are present. Now that large amounts of molecular and ecological data are increasingly accessible in microbial experimental ecosystems, it is worthwhile to tackle the questions of their complex hierarchical dynamics. Here, we propose an approach that combines microbial experimental ecosystems and a hierarchical dynamic model named population-reaction model. We present a simple microbial experimental ecosystem as an example and show how the system can be analyzed by a population-reaction model. We also show that population-reaction models can be applied to various ecological concepts, such as predator-prey interactions, climate change, evolution, and stability of diversity. Our approach will reveal a path to the general understanding of various ecosystems and organisms. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Modeling error in experimental assays using the bootstrap principle: Understanding discrepancies between assays using different dispensing technologies

PubMed Central

Hanson, Sonya M.; Ekins, Sean; Chodera, John D.

2015-01-01

All experimental assay data contains error, but the magnitude, type, and primary origin of this error is often not obvious. Here, we describe a simple set of assay modeling techniques based on the bootstrap principle that allow sources of error and bias to be simulated and propagated into assay results. We demonstrate how deceptively simple operations—such as the creation of a dilution series with a robotic liquid handler—can significantly amplify imprecision and even contribute substantially to bias. To illustrate these techniques, we review an example of how the choice of dispensing technology can impact assay measurements, and show how large contributions to discrepancies between assays can be easily understood and potentially corrected for. These simple modeling techniques—illustrated with an accompanying IPython notebook—can allow modelers to understand the expected error and bias in experimental datasets, and even help experimentalists design assays to more effectively reach accuracy and imprecision goals. PMID:26678597

A simple experimental method to study depigmenting agents.

PubMed

Abella, M L; de Rigal, J; Neveux, S

2007-08-01

The first objective of the study was to verify that a controlled UV exposure of four areas of the forearms together with randomized product application enabled to compare treatment efficacy and then to compare the depigmenting efficacy of different products with a simple experimental method. Sixteen volunteers received 0.7 minimal erythermal dose for four consecutive days. Products tested were ellagic acid (0.5%), vitamin C (5%) and C8-LHA (2%). Product application started 72 h post last exposure, was repeated for 42 days, the control zone being exposed, non-treated. Colour measurements included Chromameter, Chromasphere, Spectro-colorimeter and visual assessment. Comparison of colour values at day 1 and at day 7 showed that all zones were comparably tanned, allowing a rigorous comparison of the treatments. We report a new simple experimental model, which enables the rapid comparison of different depigmenting products. The efficacy and good tolerance of C8-LHA make it an excellent candidate for the treatment of hyperpigmentory disorders.

Solid-Liquid Lithium Electrolyte Nanocomposites Derived from Porous Molecular Cages.

PubMed

Petronico, Aaron; Moneypenny, Timothy P; Nicolau, Bruno G; Moore, Jeffrey S; Nuzzo, Ralph G; Gewirth, Andrew A

2018-06-20

We demonstrate that solid-liquid nanocomposites derived from porous organic cages are effective lithium ion electrolytes at room temperature. A solid-liquid electrolyte nanocomposite (SLEN) fabricated from a LiTFSI/DME electrolyte system and a porous organic cage exhibits ionic conductivity on the order of 1 × 10 -3 S cm -1 . With an experimentally measured activation barrier of 0.16 eV, this composite is characterized as a superionic conductor. Furthermore, the SLEN displays excellent oxidative stability up to 4.7 V vs Li/Li + . This simple three-component system enables the rational design of electrolytes from tunable discrete molecular architectures.

The mini-O, a digital superhet, or a truly low-cost Omega navigation receiver

NASA Technical Reports Server (NTRS)

Burhans, R. W.

1975-01-01

A quartz tuning fork filter circuit and some unique CMOS clock logic methods provide a very simple OMEGA-VLF receiver with true hyperbolic station pair phase difference outputs. An experimental system was implemented on a single battery-operated circuit board requiring only an external antenna preamplifier, and LOP output recorder. A bench evaluation and preliminary navigation tests indicate the technique is viable and can provide very low-cost OMEGA measurement systems. The method is promising for marine use with small boats in the present form, but might be implemented in conjunction with digital microprocessors for airborne navigation aids.

Measurement of whole tire profile

NASA Astrophysics Data System (ADS)

Yang, Yongyue; Jiao, Wenguang

2010-08-01

In this paper, a precision measuring device is developed for obtaining characteristic curve of tire profile and its geometric parameters. It consists of a laser displacement measurement unit, a closed-loop precision two-dimensional coordinate table, a step motor control system and a fast data acquisition and analysis system. Based on the laser trigonometry, a data map of tire profile and coordinate values of all points can be obtained through corresponding data transformation. This device has a compact structure, a convenient control, a simple hardware circuit design and a high measurement precision. Experimental results indicate that measurement precision can meet the customer accuracy requirement of +/-0.02 mm.

Evidence of a Critical Phase Transition in Purely Temporal Dynamics with Long-Delayed Feedback

NASA Astrophysics Data System (ADS)

Faggian, Marco; Ginelli, Francesco; Marino, Francesco; Giacomelli, Giovanni

2018-04-01

Experimental evidence of an absorbing phase transition, so far associated with spatiotemporal dynamics, is provided in a purely temporal optical system. A bistable semiconductor laser, with long-delayed optoelectronic feedback and multiplicative noise, shows the peculiar features of a critical phenomenon belonging to the directed percolation universality class. The numerical study of a simple, effective model provides accurate estimates of the transition critical exponents, in agreement with both theory and our experiment. This result pushes forward a hard equivalence of nontrivial stochastic, long-delayed systems with spatiotemporal ones and opens a new avenue for studying out-of-equilibrium universality classes in purely temporal dynamics.

Portable Dextrous Force Feedback Master for robot telemanipulation (PDMFF)

NASA Technical Reports Server (NTRS)

Burdea, Grigore C.; Speeter, Thomas H.

1989-01-01

A major drawback of open loop masters is a lack of force feedback, limiting their ability to perform complex tasks such as assembly and repair. Researchers present a simple dextrous force feedback master for computer assisted telemanipulation. The device is compact, portable and can be held in the operator hand, without the need for a special joystick or console. The system is capable of both position feed forward and force feedback, using electronic position sensors and a pneumatic micro-actuator. The level of forces exercised by the pneumatic actuator is such that near rigidity may be attained. Experimental results showing good system linearity and small time lag are given.

Experimental test of the variability of G using Viking lander ranging data

NASA Technical Reports Server (NTRS)

Hellings, R. W.; Adams, P. J.; Anderson, J. D.; Keesey, M. S.; Lau, E. L.; Standish, E. M.; Canuto, V. M.; Goldman, I.

1983-01-01

Results are presented from the analysis of solar-system astrometric data, notably the range data to the Viking landers on Mars. A least-squares fit of the parameters of the solar system model to these data limits a simple time variation in the effective Newtonian gravitational constant to (2 + or - 4) x 10 to the -12th/yr and a rate of drift of atomic clocks relative to the implicit clock of relativistic dynamics to (1 + or - 8) x 10 to the -12th/yr. The error limits quoted are the result of uncertainties in the masses of the asteroids.

Criticality of Adaptive Control Dynamics

NASA Astrophysics Data System (ADS)

Patzelt, Felix; Pawelzik, Klaus

2011-12-01

We show, that stabilization of a dynamical system can annihilate observable information about its structure. This mechanism induces critical points as attractors in locally adaptive control. It also reveals, that previously reported criticality in simple controllers is caused by adaptation and not by other controller details. We apply these results to a real-system example: human balancing behavior. A model of predictive adaptive closed-loop control subject to some realistic constraints is introduced and shown to reproduce experimental observations in unprecedented detail. Our results suggests, that observed error distributions in between the Lévy and Gaussian regimes may reflect a nearly optimal compromise between the elimination of random local trends and rare large errors.

Universal Parameterization of Absorption Cross Sections

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

1997-01-01

This paper presents a simple universal parameterization of total reaction cross sections for any system of colliding nuclei that is valid for the entire energy range from a few AMeV to a few AGeV. The universal picture presented here treats proton-nucleus collision as a special case of nucleus-nucleus collision, where the projectile has charge and mass number of one. The parameters are associated with the physics of the collision system. In general terms, Coulomb interaction modifies cross sections at lower energies, and the effects of Pauli blocking are important at higher energies. The agreement between the calculated and experimental data is better than all earlier published results.

Ballistic and diffusive dynamics in a two-dimensional ideal gas of macroscopic chaotic Faraday waves.

PubMed

Welch, Kyle J; Hastings-Hauss, Isaac; Parthasarathy, Raghuveer; Corwin, Eric I

2014-04-01

We have constructed a macroscopic driven system of chaotic Faraday waves whose statistical mechanics, we find, are surprisingly simple, mimicking those of a thermal gas. We use real-time tracking of a single floating probe, energy equipartition, and the Stokes-Einstein relation to define and measure a pseudotemperature and diffusion constant and then self-consistently determine a coefficient of viscous friction for a test particle in this pseudothermal gas. Because of its simplicity, this system can serve as a model for direct experimental investigation of nonequilibrium statistical mechanics, much as the ideal gas epitomizes equilibrium statistical mechanics.

Transition to chaos of a vertical collapsible tube conveying air flow

NASA Astrophysics Data System (ADS)

Castillo Flores, F.; Cros, A.

2009-05-01

"Sky dancers", the large collapsible tubes used as advertising, are studied in this work through a simple experimental device. Our study is devoted to the nonlinear dynamics of this system and to its transition to chaos. Firstly, we have shown that after a collapse occurs, the air fills the tube at a different speed rate from the flow velocity. Secondly, the temporal intermittency is studied as the flow rate is increased. A statistical analysis shows that the chaotic times maintain roughly the same value by increasing air speed. On the other hand, laminar times become shorter, until the system reaches a completely chaotic state.

Addition and subtraction operation of optical orbital angular momentum with dielectric metasurfaces

NASA Astrophysics Data System (ADS)

Yi, Xunong; Li, Ying; Ling, Xiaohui; Liu, Yachao; Ke, Yougang; Fan, Dianyuan

2015-12-01

In this work, we propose a simple approach to realize addition and subtraction operation of optical orbital angular momentum (OAM) based on dielectric metasurfaces. The spin-orbit interaction of light in spatially inhomogeneous and anisotropic metasurfaces results in the spin-to-orbital angular momentum conversion. The subtraction system of OAM consists of two cascaded metasurfaces, while the addition system of OAM is constituted by inserting a half waveplate (HWP) between the two metasurfaces. Our experimental results are in good agreement with the theoretical calculation. These results could be useful for OAM-carrying beams applied in optical communication, information processing, etc.

Three-Dimensional Planetary Surface Tracking Based on a Simple Ultra-Wideband Impulse-Radio Infrastructure

NASA Technical Reports Server (NTRS)

Barton, Richard J.; Ni, David; Ngo, Phong

2010-01-01

Several prototype ultra-wideband (UWB) impulse-radio (IR) tracking systems are currently under development at NASA Johnson Space Center (JSC). These systems are being studied for use in tracking of Lunar/Mars rovers and astronauts during early exploration missions when satellite navigation systems (such as GPS) are not available. To date, the systems that have been designed and tested are intended only for two-dimensional location and tracking, but these designs can all be extended to three-dimensional tracking with only minor modifications and increases in complexity. In this presentation, we will briefly review the design and performance of two of the current 2-D systems: one designed specifically for short-range, extremely high-precision tracking (approximately 1-2 cm resolution) and the other designed specifically for much longer range tracking with less stringent precision requirements (1-2 m resolution). We will then discuss a new multi-purpose system design based on a simple UWB-IR architecture that can be deployed easily on a planetary surface to support arbitrary three-dimensional localization and tracking applications. We will discuss utilization of this system as an infrastructure to provide both short-range and long-range tracking and analyze the localization performance of the system in several different configurations. We will give theoretical performance bounds for some canonical system configurations and compare these performance bounds with both numerical simulations of the system as well as actual experimental system performance evaluations.

Theory and experiments in model-based space system anomaly management

NASA Astrophysics Data System (ADS)

Kitts, Christopher Adam

This research program consists of an experimental study of model-based reasoning methods for detecting, diagnosing and resolving anomalies that occur when operating a comprehensive space system. Using a first principles approach, several extensions were made to the existing field of model-based fault detection and diagnosis in order to develop a general theory of model-based anomaly management. Based on this theory, a suite of algorithms were developed and computationally implemented in order to detect, diagnose and identify resolutions for anomalous conditions occurring within an engineering system. The theory and software suite were experimentally verified and validated in the context of a simple but comprehensive, student-developed, end-to-end space system, which was developed specifically to support such demonstrations. This space system consisted of the Sapphire microsatellite which was launched in 2001, several geographically distributed and Internet-enabled communication ground stations, and a centralized mission control complex located in the Space Technology Center in the NASA Ames Research Park. Results of both ground-based and on-board experiments demonstrate the speed, accuracy, and value of the algorithms compared to human operators, and they highlight future improvements required to mature this technology.

Multiple-input multiple-output visible light communication system based on disorder dispersion components

NASA Astrophysics Data System (ADS)

Yang, Tao; Zhang, Qi; Hao, Yue; Zhou, Xin-hui; Yi, Ming-dong; Wei, Wei; Huang, Wei; Li, Xing-ao

2017-10-01

A multiple-input multiple-output visible light communication (VLC) system based on disorder dispersion components is presented. Instead of monochromatic sources and large size photodetectors used in the traditional VLC systems, broadband sources with different spectra act as the transmitters and a compact imaging chip sensor accompanied by a disorder dispersion component and a calculating component serve as the receivers in the proposed system. This system has the merits of small size, more channels, simple structure, easy integration, and low cost. Simultaneously, the broadband sources are suitable to act as illumination sources for their white color. A regularized procedure is designed to solve a matrix equation for decoding the signals at the receivers. A proof-of-concept experiment using on-off keying modulation has been done to prove the feasibility of the design. The experimental results show that the signals decoded by the receivers fit well with those generated from the transmitters, but the bit error ratio is increased with the number of the signal channels. The experimental results can be further improved using a high-speed charge-coupled device, decreasing noises, and increasing the distance between the transmitters and the receivers.

Eco-evolutionary Red Queen dynamics regulate biodiversity in a metabolite-driven microbial system.

PubMed

Bonachela, Juan A; Wortel, Meike T; Stenseth, Nils Chr

2017-12-15

The Red Queen Hypothesis proposes that perpetual co-evolution among organisms can result from purely biotic drivers. After more than four decades, there is no satisfactory understanding as to which mechanisms trigger Red Queen dynamics or their implications for ecosystem features such as biodiversity. One reason for such a knowledge gap is that typical models are complicated theories where limit cycles represent an idealized Red Queen, and therefore cannot be used to devise experimental setups. Here, we bridge this gap by introducing a simple model for microbial systems able to show Red Queen dynamics. We explore diverse biotic sources that can drive the emergence of the Red Queen and that have the potential to be found in nature or to be replicated in the laboratory. Our model enables an analytical understanding of how Red Queen dynamics emerge in our setup, and the translation of model terms and phenomenology into general underlying mechanisms. We observe, for example, that in our system the Red Queen offers opportunities for the increase of biodiversity by facilitating challenging conditions for intraspecific dominance, whereas stasis tends to homogenize the system. Our results can be used to design and engineer experimental microbial systems showing Red Queen dynamics.

Computer Series, 107.

ERIC Educational Resources Information Center

Birk, James P., Ed.

1989-01-01

Presented is a simple laboratory set-up for teaching microprocessor-controlled data acquisition as a part of an instrumental analysis course. Discussed are the experimental set-up, experimental procedures, and technical considerations for this technique. (CW)

Microscale Organic Laboratory: IV. A Simple and Rapid Procedure for Carrying Out Wittig Reactions.

ERIC Educational Resources Information Center

Pike, R. M.; And Others

1986-01-01

Describes two examples where synthetic salt-base mixtures are used in a microscale organic laboratory program as a simple and quick procedure for carrying out Wittig reactions. Both experimental procedures are outlined and discussed. (TW)

Simple Apparatus for Measuring the Critical Properties of Gases

ERIC Educational Resources Information Center

Donaldson, G. B.

1973-01-01

Describes the construction and operational procedures of a simple setup which enables undergraduate students to conduct experiments on critical phenomena in gases. Indicates that the experimental features are proved comparable to those of the Reamer and Sage apparatus. (CC)

An Experimental Study of the Ground Transportation System (GTS) Model in the NASA Ames 7- by 10-Ft Wind Tunnel

NASA Technical Reports Server (NTRS)

Storms, Bruce L.; Ross, James C.; Heineck, James T.; Walker, Stephen M.; Driver, David M.; Zilliac, Gregory G.; Bencze, Daniel P. (Technical Monitor)

2001-01-01

The 1/8-scale Ground Transportation System (GTS) model was studied experimentally in the NASA Ames 7- by 10-Ft Wind Tunnel. Designed for validation of computational fluid dynamics (CFD), the GTS model has a simplified geometry with a cab-over-engine design and no tractor-trailer gap. As a further simplification, all measurements of the GTS model were made without wheels. Aerodynamic boattail plates were also tested on the rear of the trailer to provide a simple geometry modification for computation. The experimental measurements include body-axis drag, surface pressures, surface hot-film anemometry, oil-film interferometry, and 3-D particle image velocimetry (PIV). The wind-averaged drag coefficient with and without boattail plates was 0.225 and 0.277, respectively. PIV measurements behind the model reveal a significant reduction in the wake size due to the flow turning provided by the boattail plates. Hot-film measurements on the side of the cab indicate laminar separation with turbulent reattachment within 0.08 trailer width for zero and +/- 10 degrees yaw. Oil film interferometry provided quantitative measurements of skin friction and qualitative oil flow images. A complete set of the experimental data and the surface definition of the model are included on a CD-ROM for further analysis and comparison.

A Thermal Management Systems Model for the NASA GTX RBCC Concept

NASA Technical Reports Server (NTRS)

Traci, Richard M.; Farr, John L., Jr.; Laganelli, Tony; Walker, James (Technical Monitor)

2002-01-01

The Vehicle Integrated Thermal Management Analysis Code (VITMAC) was further developed to aid the analysis, design, and optimization of propellant and thermal management concepts for advanced propulsion systems. The computational tool is based on engineering level principles and models. A graphical user interface (GUI) provides a simple and straightforward method to assess and evaluate multiple concepts before undertaking more rigorous analysis of candidate systems. The tool incorporates the Chemical Equilibrium and Applications (CEA) program and the RJPA code to permit heat transfer analysis of both rocket and air breathing propulsion systems. Key parts of the code have been validated with experimental data. The tool was specifically tailored to analyze rocket-based combined-cycle (RBCC) propulsion systems being considered for space transportation applications. This report describes the computational tool and its development and verification for NASA GTX RBCC propulsion system applications.

Overshoot in biological systems modelled by Markov chains: a non-equilibrium dynamic phenomenon.

PubMed

Jia, Chen; Qian, Minping; Jiang, Daquan

2014-08-01

A number of biological systems can be modelled by Markov chains. Recently, there has been an increasing concern about when biological systems modelled by Markov chains will perform a dynamic phenomenon called overshoot. In this study, the authors found that the steady-state behaviour of the system will have a great effect on the occurrence of overshoot. They showed that overshoot in general cannot occur in systems that will finally approach an equilibrium steady state. They further classified overshoot into two types, named as simple overshoot and oscillating overshoot. They showed that except for extreme cases, oscillating overshoot will occur if the system is far from equilibrium. All these results clearly show that overshoot is a non-equilibrium dynamic phenomenon with energy consumption. In addition, the main result in this study is validated with real experimental data.

Tutorial on Fourier space coverage for scattering experiments, with application to SAR

NASA Astrophysics Data System (ADS)

Deming, Ross W.

2010-04-01

The Fourier Diffraction Theorem relates the data measured during electromagnetic, optical, or acoustic scattering experiments to the spatial Fourier transform of the object under test. The theorem is well-known, but since it is based on integral equations and complicated mathematical expansions, the typical derivation may be difficult for the non-specialist. In this paper, the theorem is derived and presented using simple geometry, plus undergraduatelevel physics and mathematics. For practitioners of synthetic aperture radar (SAR) imaging, the theorem is important to understand because it leads to a simple geometric and graphical understanding of image resolution and sampling requirements, and how they are affected by radar system parameters and experimental geometry. Also, the theorem can be used as a starting point for imaging algorithms and motion compensation methods. Several examples are given in this paper for realistic scenarios.

A miniature extrinsic fiber Fabry-Perot pressure sensor based on fiber etching

NASA Astrophysics Data System (ADS)

Ge, Yixian; Zhou, Junping; Wang, Tingting

2011-11-01

A miniature fiber optic pressure sensor based on Fabry-Perot interference fabricated on the tip of a single mode (SM) fiber is presented. The sensor measures only 125μm in diameter. A Fabry-Perot cavity and a thin silica diaphragm are fabricated by simple techniques involving only cleaving, wet chemical etching and fusion splicing. Interference pattern of the sensor is analyzed and issues in sensor design are discussed. The overall chemical reaction of the fiber wet etching is specifically represented. Pressure testing system is carried out. By tracing a peak point in the interference spectrum, the gap length of the sensor can be demodulated. Experimental results show the sensor has a good linearity. The sensor is made entirely of fused silica, whose structure has good stability, cabinet, simple for fabrication and low cost.

Design of arbitrarily homogeneous permanent magnet systems for NMR and MRI: theory and experimental developments of a simple portable magnet.

PubMed

Hugon, Cedric; D'Amico, Francesca; Aubert, Guy; Sakellariou, Dimitris

2010-07-01

Starting from general results of magnetostatics, we give fundamental considerations on the design and characterization of permanent magnets for NMR based on harmonic analysis and symmetry. We then propose a simple geometry that takes advantage of some of these considerations and discuss the practical aspects of the assembly of a real magnet based on this geometry, involving the characterization of its elements, the optimization of the layout and the correction of residual inhomogeneities due to material and geometry imperfections. We report with this low-cost, light-weight magnet (100 euros and 1.8 kg including the aluminum frame) a field of 120 mT (5.1 MHz proton) with a 10 ppm natural homogeneity over a sphere of 1.5 mm in diameter. Copyright (c) 2010 Elsevier Inc. All rights reserved.

On the use of video projectors for three-dimensional scanning

NASA Astrophysics Data System (ADS)

Juarez-Salazar, Rigoberto; Diaz-Ramirez, Victor H.; Robledo-Sanchez, Carlos; Diaz-Gonzalez, Gerardo

2017-08-01

Structured light projection is one of the most useful methods for accurate three-dimensional scanning. Video projectors are typically used as the illumination source. However, because video projectors are not designed for structured light systems, some considerations such as gamma calibration must be taken into account. In this work, we present a simple method for gamma calibration of video projectors. First, the experimental fringe patterns are normalized. Then, the samples of the fringe patterns are sorted in ascending order. The sample sorting leads to a simple three-parameter sine curve that is fitted using the Gauss-Newton algorithm. The novelty of this method is that the sorting process removes the effect of the unknown phase. Thus, the resulting gamma calibration algorithm is significantly simplified. The feasibility of the proposed method is illustrated in a three-dimensional scanning experiment.

A simple transferable adaptive potential to study phase separation in large-scale xMgO-(1-x)SiO2 binary glasses.

PubMed

Bidault, Xavier; Chaussedent, Stéphane; Blanc, Wilfried

2015-10-21

A simple transferable adaptive model is developed and it allows for the first time to simulate by molecular dynamics the separation of large phases in the MgO-SiO2 binary system, as experimentally observed and as predicted by the phase diagram, meaning that separated phases have various compositions. This is a real improvement over fixed-charge models, which are often limited to an interpretation involving the formation of pure clusters, or involving the modified random network model. Our adaptive model, efficient to reproduce known crystalline and glassy structures, allows us to track the formation of large amorphous Mg-rich Si-poor nanoparticles in an Mg-poor Si-rich matrix from a 0.1MgO-0.9SiO2 melt.

A simple and sensitive fluorescent sensor for methyl parathion based on L-tyrosine methyl ester functionalized carbon dots.

PubMed

Hou, Juying; Dong, Jing; Zhu, Haishuang; Teng, Xue; Ai, Shiyun; Mang, Minglin

2015-06-15

In this paper, a simple and sensitive fluorescent sensor for methyl parathion is developed based on L-tyrosine methyl ester functionalized carbon dots (Tyr-CDs) and tyrosinase system. The carbon dots are obtained by simple hydrothermal reaction using citric acid as carbon resource and L-tyrosine methyl ester as modification reagent. The carbon dots are characterized by transmission electron microscope, high resolution transmission electron microscopy, X-ray diffraction spectrum, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The carbon dots show strong and stable photoluminescence with a quantum yield of 3.8%. Tyrosinase can catalyze the oxidation of tyrosine methyl ester on the surface of carbon dots to corresponding quinone products, which can quench the fluorescence of carbon dots. When organophosphorus pesticides (OPs) are introduced in system, they can decrease the enzyme activity, thus decrease the fluorescence quenching rate. Methyl parathion, as a model of OPs, was detected. Experimental results show that the enzyme inhibition rate is proportional to the logarithm of the methyl parathion concentration in the range 1.0×10(-10)-1.0×10(-4) M with the detection limit (S/N=3) of 4.8×10(-11) M. This determination method shows a low detection limit, wide linear range, good selectivity and high reproducibility. This sensing system has been successfully used for the analysis of cabbage, milk and fruit juice samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Plasma breakdown in a capacitively-coupled radiofrequency argon discharge

NASA Astrophysics Data System (ADS)

Smith, H. B.; Charles, C.; Boswell, R. W.

1998-10-01

Low pressure, capacitively-coupled rf discharges are widely used in research and commercial ventures. Understanding of the non-equilibrium processes which occur in these discharges during breakdown is of interest, both for industrial applications and for a deeper understanding of fundamental plasma behaviour. The voltage required to breakdown the discharge V_brk has long been known to be a strong function of the product of the neutral gas pressure and the electrode seperation (pd). This paper investigates the dependence of V_brk on pd in rf systems using experimental, computational and analytic techniques. Experimental measurements of V_brk are made for pressures in the range 1 -- 500 mTorr and electrode separations of 2 -- 20 cm. A Paschen-style curve for breakdown in rf systems is developed which has the minimum breakdown voltage at a much smaller pd value, and breakdown voltages which are significantly lower overall, than for Paschen curves obtained from dc discharges. The differences between the two systems are explained using a simple analytic model. A Particle-in-Cell simulation is used to investigate a similar pd range and examine the effect of the secondary emission coefficient on the rf breakdown curve, particularly at low pd values. Analytic curves are fitted to both experimental and simulation results.

Level Alignment as Descriptor for Semiconductor/Catalyst Systems in Water Splitting: The Case of Hematite/Cobalt Hexacyanoferrate Photoanodes.

PubMed

Hegner, Franziska Simone; Cardenas-Morcoso, Drialys; Giménez, Sixto; López, Núria; Galan-Mascaros, Jose Ramon

2017-11-23

The realization of artificial photosynthesis may depend on the efficient integration of photoactive semiconductors and catalysts to promote photoelectrochemical water splitting. Many efforts are currently devoted to the processing of multicomponent anodes and cathodes in the search for appropriate synergy between light absorbers and active catalysts. No single material appears to combine both features. Many experimental parameters are key to achieve the needed synergy between both systems, without clear protocols for success. Herein, we show how computational chemistry can shed some light on this cumbersome problem. DFT calculations are useful to predict adequate energy-level alignment for thermodynamically favored hole transfer. As proof of concept, we experimentally confirmed the limited performance enhancement in hematite photoanodes decorated with cobalt hexacyanoferrate as a competent water-oxidation catalyst. Computational methods describe the misalignment of their energy levels, which is the origin of this mismatch. Photoelectrochemical studies indicate that the catalyst exclusively shifts the hematite surface state to lower potentials, which therefore reduces the onset for water oxidation. Although kinetics will still depend on interface architecture, our simple theoretical approach may identify and predict plausible semiconductor/catalyst combinations, which will speed up experimental work towards promising photoelectrocatalytic systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frustration in Biomolecules

PubMed Central

Ferreiro, Diego U.; Komives, Elizabeth A.; Wolynes, Peter G.

2014-01-01

Biomolecules are the prime information processing elements of living matter. Most of these inanimate systems are polymers that compute their own structures and dynamics using as input seemingly random character strings of their sequence, following which they coalesce and perform integrated cellular functions. In large computational systems with a finite interaction-codes, the appearance of conflicting goals is inevitable. Simple conflicting forces can lead to quite complex structures and behaviors, leading to the concept of frustration in condensed matter. We present here some basic ideas about frustration in biomolecules and how the frustration concept leads to a better appreciation of many aspects of the architecture of biomolecules, and how biomolecular structure connects to function. These ideas are simultaneously both seductively simple and perilously subtle to grasp completely. The energy landscape theory of protein folding provides a framework for quantifying frustration in large systems and has been implemented at many levels of description. We first review the notion of frustration from the areas of abstract logic and its uses in simple condensed matter systems. We discuss then how the frustration concept applies specifically to heteropolymers, testing folding landscape theory in computer simulations of protein models and in experimentally accessible systems. Studying the aspects of frustration averaged over many proteins provides ways to infer energy functions useful for reliable structure prediction. We discuss how frustration affects folding mechanisms. We review here how a large part of the biological functions of proteins are related to subtle local physical frustration effects and how frustration influences the appearance of metastable states, the nature of binding processes, catalysis and allosteric transitions. We hope to illustrate how Frustration is a fundamental concept in relating function to structural biology. PMID:25225856

Two-Electron Transfer Pathways.

PubMed

Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

2015-06-18

The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple electrons in condensed-phase redox systems, including multiple-electron redox species, multimetallic/multielectron redox catalysts, and multiexciton excited states.

Detonation Product EOS Studies: Using ISLS to Refine Cheetah

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

Zaug, J M; Howard, W M; Fried, L E

2001-08-08

Knowledge of an effective interatomic potential function underlies any effort to predict or rationalize the properties of solids and liquids. The experiments we undertake are directed towards determination of equilibrium and dynamic properties of simple fluids at densities sufficiently high that traditional computational methods and semi-empirical forms successful at ambient conditions may require reconsideration. In this paper we present high-pressure and temperature experimental sound speed data on a simple fluid, methanol. Impulsive Stimulated Light Scattering (ISLS) conducted on diamond-anvil cell (DAC) encapsulated samples offers an experimental approach to determine cross-pair potential interactions through equation of state determinations. In addition themore » kinetics of structural relaxation in fluids can be studied. We compare our experimental results with our thermochemical computational model Cheetah. Computational models are systematically improved with each addition of experimental data.« less

A mathematical model of physiological processes and its application to the study of aging

NASA Technical Reports Server (NTRS)

Hibbs, A. R.; Walford, R. L.

1989-01-01

The behavior of a physiological system which, after displacement, returns by homeostatic mechanisms to its original condition can be described by a simple differential equation in which the "recovery time" is a parameter. Two such systems, which influence one another, can be linked mathematically by the use of "coupling" or "feedback" coefficients. These concepts are the basis for many mathematical models of physiological behavior, and we describe the general nature of such models. Next, we introduce the concept of a "fatal limit" for the displacement of a physiological system, and show how measures of such limits can be included in mathematical models. We show how the numerical values of such limits depend on the values of other system parameters, i.e., recovery times and coupling coefficients, and suggest ways of measuring all these parameters experimentally, for example by monitoring changes induced by X-irradiation. Next, we discuss age-related changes in these parameters, and show how the parameters of mortality statistics, such as the famous Gompertz parameters, can be derived from experimentally measurable changes. Concepts of onset-of-aging, critical or fatal limits, equilibrium value (homeostasis), recovery times and coupling constants are involved. Illustrations are given using published data from mouse and rat populations. We believe that this method of deriving survival patterns from model that is experimentally testable is unique.

Advanced Method to Estimate Fuel Slosh Simulation Parameters

NASA Technical Reports Server (NTRS)

Schlee, Keith; Gangadharan, Sathya; Ristow, James; Sudermann, James; Walker, Charles; Hubert, Carl

2005-01-01

The nutation (wobble) of a spinning spacecraft in the presence of energy dissipation is a well-known problem in dynamics and is of particular concern for space missions. The nutation of a spacecraft spinning about its minor axis typically grows exponentially and the rate of growth is characterized by the Nutation Time Constant (NTC). For launch vehicles using spin-stabilized upper stages, fuel slosh in the spacecraft propellant tanks is usually the primary source of energy dissipation. For analytical prediction of the NTC this fuel slosh is commonly modeled using simple mechanical analogies such as pendulums or rigid rotors coupled to the spacecraft. Identifying model parameter values which adequately represent the sloshing dynamics is the most important step in obtaining an accurate NTC estimate. Analytic determination of the slosh model parameters has met with mixed success and is made even more difficult by the introduction of propellant management devices and elastomeric diaphragms. By subjecting full-sized fuel tanks with actual flight fuel loads to motion similar to that experienced in flight and measuring the forces experienced by the tanks these parameters can be determined experimentally. Currently, the identification of the model parameters is a laborious trial-and-error process in which the equations of motion for the mechanical analog are hand-derived, evaluated, and their results are compared with the experimental results. The proposed research is an effort to automate the process of identifying the parameters of the slosh model using a MATLAB/SimMechanics-based computer simulation of the experimental setup. Different parameter estimation and optimization approaches are evaluated and compared in order to arrive at a reliable and effective parameter identification process. To evaluate each parameter identification approach, a simple one-degree-of-freedom pendulum experiment is constructed and motion is induced using an electric motor. By applying the estimation approach to a simple, accurately modeled system, its effectiveness and accuracy can be evaluated. The same experimental setup can then be used with fluid-filled tanks to further evaluate the effectiveness of the process. Ultimately, the proven process can be applied to the full-sized spinning experimental setup to quickly and accurately determine the slosh model parameters for a particular spacecraft mission. Automating the parameter identification process will save time, allow more changes to be made to proposed designs, and lower the cost in the initial design stages.

Experimental determination of interfacial tension by different dynamical methods under simple shear flow conditions with a novel computer-controlled parallel band apparatus.

PubMed

Megías-Alguacil, David; Fischer, Peter; Windhab, Erich J

2004-06-15

We present experimental investigations on droplet deformation under simple shear flow conditions, using a computer-controlled parallel band apparatus and an optical device which allows us to record the time dependence of the droplet shape. Several methods are applied to determine the interfacial tension from the observed shape and relaxation mechanism. Specific software developed in our laboratory allows the droplet to be fixed in a certain position for extended times, in fact, indefinite. This is an advantage over most other work done in this area, where only limited time is available. In our experiments, the transient deformation of sheared droplets can be observed to reach the steady state. The measured systems were Newtonian, both droplet and fluid phase. Droplet deformation, orientation angle and retraction were studied and compared to several models. The interfacial tension of the different systems was calculated using the theories of Taylor, Rallison, and Hinch and Acrivos. The results obtained from the analysis of the droplet deformation were in very good agreement with drop detachment experiments of Feigl and co-workers. The study of orientation angle shows qualitative agreement to the theory of Hinch and Acrivos but reveals larger quantitative discrepancies for several empirical fitting parameters of the used model. Analysis of the relaxation of sheared drops provided estimates of the interfacial tension that were in very good agreement with the steady-state measurements.

Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

NASA Astrophysics Data System (ADS)

Golinelli, Nicola; Spaggiari, Andrea

2018-07-01

This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model.

Thermal shock resistance of ceramic matrix composites

NASA Technical Reports Server (NTRS)

Carper, D. M.; Nied, H. F.

1993-01-01

The experimental and analytical investigation of the thermal shock phenomena in ceramic matrix composites is detailed. The composite systems examined were oxide-based, consisting of an aluminosilicate matrix with either polycrystalline aluminosilicate or single crystal alumina fiber reinforcement. The program was divided into three technical tasks; baseline mechanical properties, thermal shock modeling, and thermal shock testing. The analytical investigation focused on the development of simple expressions for transient thermal stresses induced during thermal shock. The effect of various material parameters, including thermal conductivity, elastic modulus, and thermal expansion, were examined analytically for their effect on thermal shock performance. Using a simple maximum stress criteria for each constituent, it was observed that fiber fracture would occur only at the most extreme thermal shock conditions and that matrix fracture, splitting parallel to the reinforcing fiber, was to be expected for most practical cases. Thermal shock resistance for the two material systems was determined experimentally by subjecting plates to sudden changes in temperature on one surface while maintaining the opposite surface at a constant temperature. This temperature change was varied in severity (magnitude) and in number of shocks applied to a given sample. The results showed that for the most severe conditions examined that only surface matrix fracture was present with no observable fiber fracture. The impact of this damage on material performance was limited to the matrix dominated properties only. Specifically, compression strength was observed to decrease by as much as 50 percent from the measured baseline.