Hierarchical MAS based control strategy for microgrid

Energy Technology Data Exchange (ETDEWEB)

Xiao, Z.; Li, T.; Huang, M.; Shi, J.; Yang, J.; Yu, J. [School of Information Science and Engineering, Yunnan University, Kunming 650091 (China); Xiao, Z. [School of Electrical and Electronic Engineering, Nanyang Technological University, Western Catchment Area, 639798 (Singapore); Wu, W. [Communication Branch of Yunnan Power Grid Corporation, Kunming, Yunnan 650217 (China)

2010-09-15

Microgrids have become a hot topic driven by the dual pressures of environmental protection concerns and the energy crisis. In this paper, a challenge for the distributed control of a modern electric grid incorporating clusters of residential microgrids is elaborated and a hierarchical multi-agent system (MAS) is proposed as a solution. The issues of how to realize the hierarchical MAS and how to improve coordination and control strategies are discussed. Based on MATLAB and ZEUS platforms, bilateral switching between grid-connected mode and island mode is performed under control of the proposed MAS to enhance and support its effectiveness. (authors)

MAS NMR of HIV-1 protein assemblies

Science.gov (United States)

Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

2015-04-01

The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

Magnetization Switching of a Co /Pt Multilayered Perpendicular Nanomagnet Assisted by a Microwave Field with Time-Varying Frequency

Science.gov (United States)

Suto, Hirofumi; Kanao, Taro; Nagasawa, Tazumi; Mizushima, Koichi; Sato, Rie

2018-05-01

Microwave-assisted magnetization switching (MAS) is attracting attention as a method for reversing nanomagnets with a high magnetic anisotropy by using a small-amplitude magnetic field. We experimentally study MAS of a perpendicularly magnetized nanomagnet by applying a microwave magnetic field with a time-varying frequency. Because the microwave field frequency can follow the nonlinear decrease of the resonance frequency, larger magnetization excitation than that in a constant-frequency microwave field is induced, which enhances the MAS effect. The switching field decreases almost linearly as the start value of the time-varying microwave field frequency increases, and it becomes smaller than the minimum switching field in a constant-frequency microwave field. To obtain this enhancement of the MAS effect, the end value of the time-varying microwave field frequency needs to be almost the same as or lower than the critical frequency for MAS in a constant-frequency microwave field. In addition, the frequency change typically needs to take 1 ns or longer to make the rate of change slow enough for the magnetization to follow the frequency change. This switching behavior is qualitatively explained by the theory based on the macrospin model.

What drives cross-border M&As in commercial banking?

NARCIS (Netherlands)

Galamhussen, Mohamed; Hennart, Jean-Francois; Pinheiro, Carlos Manuel

2016-01-01

Using a gravity model, we analyze the determinants of the probability that commercial banks in 89 acquiring countries and 118 target countries will undertake M&As over a 30-year period (1981–2010) and of the value of these M&As. We find that the value of cross-border M&As increases with the size of

Analytical–numerical global model of atmospheric-pressure radio-frequency capacitive discharges

International Nuclear Information System (INIS)

Lazzaroni, C; Chabert, P; Lieberman, M A; Lichtenberg, A J; Leblanc, A

2012-01-01

A one-dimensional hybrid analytical–numerical global model of atmospheric-pressure, radio-frequency (rf) driven capacitive discharges is developed. The feed gas is assumed to be helium with small admixtures of oxygen or nitrogen. The electrical characteristics are modeled analytically as a current-driven homogeneous discharge. The electron power balance is solved analytically to determine a time-varying Maxwellian electron temperature, which oscillates on the rf timescale. Averaging over the rf period yields effective rate coefficients for gas phase activated processes. The particle balance relations for all species are then integrated numerically to determine the equilibrium discharge parameters. The coupling of analytical solutions of the time-varying discharge and electron temperature dynamics, and numerical solutions of the discharge chemistry, allows for a fast solution of the discharge equilibrium. Variations of discharge parameters with discharge composition and rf power are determined. Comparisons are made to more accurate but numerically costly fluid models, with space and time variations, but with the range of parameters limited by computational time. (paper)

Increasing brain angiotensin converting enzyme 2 activity decreases anxiety-like behavior in male mice by activating central Mas receptors.

Science.gov (United States)

Wang, Lei; de Kloet, Annette D; Pati, Dipanwita; Hiller, Helmut; Smith, Justin A; Pioquinto, David J; Ludin, Jacob A; Oh, S Paul; Katovich, Michael J; Frazier, Charles J; Raizada, Mohan K; Krause, Eric G

2016-06-01

Over-activation of the brain renin-angiotensin system (RAS) has been implicated in the etiology of anxiety disorders. Angiotensin converting enzyme 2 (ACE2) inhibits RAS activity by converting angiotensin-II, the effector peptide of RAS, to angiotensin-(1-7), which activates the Mas receptor (MasR). Whether increasing brain ACE2 activity reduces anxiety by stimulating central MasR is unknown. To test the hypothesis that increasing brain ACE2 activity reduces anxiety-like behavior via central MasR stimulation, we generated male mice overexpressing ACE2 (ACE2 KI mice) and wild type littermate controls (WT). ACE2 KI mice explored the open arms of the elevated plus maze (EPM) significantly more than WT, suggesting increasing ACE2 activity is anxiolytic. Central delivery of diminazene aceturate, an ACE2 activator, to C57BL/6 mice also reduced anxiety-like behavior in the EPM, but centrally administering ACE2 KI mice A-779, a MasR antagonist, abolished their anxiolytic phenotype, suggesting that ACE2 reduces anxiety-like behavior by activating central MasR. To identify the brain circuits mediating these effects, we measured Fos, a marker of neuronal activation, subsequent to EPM exposure and found that ACE2 KI mice had decreased Fos in the bed nucleus of stria terminalis but had increased Fos in the basolateral amygdala (BLA). Within the BLA, we determined that ∼62% of GABAergic neurons contained MasR mRNA and expression of MasR mRNA was upregulated by ACE2 overexpression, suggesting that ACE2 may influence GABA neurotransmission within the BLA via MasR activation. Indeed, ACE2 overexpression was associated with increased frequency of spontaneous inhibitory postsynaptic currents (indicative of presynaptic release of GABA) onto BLA pyramidal neurons and central infusion of A-779 eliminated this effect. Collectively, these results suggest that ACE2 may reduce anxiety-like behavior by activating central MasR that facilitate GABA release onto pyramidal neurons within the

MAS-based Distributed Coordinated Control and Optimization in Microgrid and Microgrid Clusters: A Comprehensive Overview

DEFF Research Database (Denmark)

Han, Yang; Zhang, Ke; Hong, Li

2018-01-01

The increasing integration of the distributed renewable energy sources highlights the requirement to design various control strategies for microgrids (MGs) and microgrid clusters (MGCs). The multi-agent system (MAS)-based distributed coordinated control strategies shows the benefits to balance...... the power and energy, stabilize voltage and frequency, achieve economic and coordinated operation among the MGs and MGCs. However, the complex and diverse combinations of distributed generations in multi-agent system increase the complexity of system control and operation. In order to design the optimized...... configuration and control strategy using MAS, the topology models and mathematic models such as the graph topology model, non-cooperative game model, the genetic algorithm and particle swarm optimization algorithm are summarized. The merits and drawbacks of these control methods are compared. Moreover, since...

Numerical investigations of single bubble oscillations generated by a dual frequency excitation

International Nuclear Information System (INIS)

Guédra, Matthieu; Inserra, Claude; Gilles, Bruno; Béra, Jean-Christophe

2015-01-01

The oscillations of a single bubble excited with a dual frequency acoustic field are numerically investigated. Computations are made for an air bubble in water exposed to an acoustic field with a linearly varying amplitude. The bubble response to an excitation containing two frequencies f 1 = 500 kHz and f 2 = 400 kHz at the same amplitude is compared to the monofrequency case where only f 1 is present. Time-frequency representations show a sharp transition in the bifrequency case, for which the low frequency component f 2 becomes resonant while the high frequency component f 1 is strongly attenuated. The temporal evolution of the power spectra reveals that the resonance of the low frequency component is correlated with the time varying mean radius of the bubble. It is also observed that the total power of the bubble response in the bifrequency case can reach almost twice the power obtained in the monofrequency case, which indicates a strong enhancement of the cavitating behavior of the bubble for this specific frequency combination. (paper)

Numerical electromagnetic frequency domain analysis with discrete exterior calculus

Science.gov (United States)

Chen, Shu C.; Chew, Weng Cho

2017-12-01

In this paper, we perform a numerical analysis in frequency domain for various electromagnetic problems based on discrete exterior calculus (DEC) with an arbitrary 2-D triangular or 3-D tetrahedral mesh. We formulate the governing equations in terms of DEC for 3-D and 2-D inhomogeneous structures, and also show that the charge continuity relation is naturally satisfied. Then we introduce a general construction for signed dual volume to incorporate material information and take into account the case when circumcenters fall outside triangles or tetrahedrons, which may lead to negative dual volume without Delaunay triangulation. Then we examine the boundary terms induced by the dual mesh and provide a systematical treatment of various boundary conditions, including perfect magnetic conductor (PMC), perfect electric conductor (PEC), Dirichlet, periodic, and absorbing boundary conditions (ABC) within this method. An excellent agreement is achieved through the numerical calculation of several problems, including homogeneous waveguides, microstructured fibers, photonic crystals, scattering by a 2-D PEC, and resonant cavities.

Radiofrequency fields in MAS solid state NMR probes

Science.gov (United States)

Tošner, Zdeněk; Purea, Armin; Struppe, Jochem O.; Wegner, Sebastian; Engelke, Frank; Glaser, Steffen J.; Reif, Bernd

2017-11-01

We present a detailed analysis of the radiofrequency (RF) field over full volume of a rotor that is generated in a solenoid coil. On top of the usually considered static distribution of amplitudes along the coil axis we describe dynamic radial RF inhomogeneities induced by sample rotation. During magic angle spinning (MAS), the mechanical rotation of the sample about the magic angle, a spin packet travels through areas of different RF fields and experiences periodical modulations of both the RF amplitude and the phase. These modulations become particularly severe at the end regions of the coil where the relative RF amplitude varies up to ±25% and the RF phase changes within ±30°. Using extensive numerical simulations we demonstrate effects of RF inhomogeneity on pulse calibration and for the ramped CP experiment performed at a wide range of MAS rates. In addition, we review various methods to map RF fields using a B0 gradient along the sample (rotor axis) for imaging purposes. Under such a gradient, a nutation experiment provides directly the RF amplitude distribution, a cross polarization experiment images the correlation of the RF fields on the two channels according to the Hartmann-Hahn matching condition, while a spin-lock experiment allows to calibrate the RF amplitude employing the rotary resonance recoupling condition. Knowledge of the RF field distribution in a coil provides key to understand its effects on performance of a pulse sequence at the spectrometer and enables to set robustness requirements in the experimental design.

Hydronephrosis alters cardiac ACE2 and Mas receptor expression in mice.

Science.gov (United States)

Zhang, Yanling; Ma, Lulu; Wu, Junyan; Chen, Tingting

2015-06-01

Hydronephrosis is characterized by substantial loss of tubules and affects renin secretion in the kidney. However, whether alterations of angiotensin-converting enzyme (ACE), ACE2 and Mas receptor in the heart are observed in hydronephrosis is unknown. Thus, we assessed these components in hydronephrotic mice treated with AT1 receptor blockade and ACE inhibitor. Hydronephrosis was induced by left ureteral ligation in Balb/C mice except sham-operated animals. The levels of cardiac ACE, ACE2 and Mas receptor were measured after treatment of losartan or enalapril. Hydronephrosis led to an increase of ACE level and a decrease of ACE2 and Mas receptor in the heart. Losartan decreased cardiac ACE level, but ACE2 and Mas receptor levels significantly increased in hydronephrotic mice (p Hydronephrosis increased cardiac ACE and suppressed ACE2 and Mas receptor levels. AT1 blockade caused sustained activation of cardiac ACE2 and Mas receptor, but ACE inhibitor had the limitation of such activation of Mas receptor in hydronephrotic animals. © The Author(s) 2015.

Numerical and analytic models of spontaneous frequency sweeping for energetic particle-driven Alfven eigenmodes

Science.gov (United States)

Wang, Ge; Berk, H. L.

2011-10-01

The frequency chirping signal arising from spontaneous a toroidial Alfven eigenmode (TAE) excited by energetic particles is studied for both numerical and analytic models. The time-dependent numerical model is based on the 1D Vlasov equation. We use a sophisticated tracking method to lock onto the resonant structure to enable the chirping frequency to be nearly constant in the calculation frame. The accuracy of the adiabatic approximation is tested during the simulation which justifies the appropriateness of our analytic model. The analytic model uses the adiabatic approximation which allows us to solve the wave evolution equation in frequency space. Then, the resonant interactions between energetic particles and TAE yield predictions for the chirping rate, wave frequency and amplitudes vs. time. Here, an adiabatic invariant J is defined on the separatrix of a chirping mode to determine the region of confinement of the wave trapped distribution function. We examine the asymptotic behavior of the chirping signal for its long time evolution and find agreement in essential features with the results of the simulation. Work supported by Department of Energy contract DE-FC02-08ER54988.

Numerical simulation and analysis for low-frequency rock physics measurements

Science.gov (United States)

Dong, Chunhui; Tang, Genyang; Wang, Shangxu; He, Yanxiao

2017-10-01

In recent years, several experimental methods have been introduced to measure the elastic parameters of rocks in the relatively low-frequency range, such as differential acoustic resonance spectroscopy (DARS) and stress-strain measurement. It is necessary to verify the validity and feasibility of the applied measurement method and to quantify the sources and levels of measurement error. Relying solely on the laboratory measurements, however, we cannot evaluate the complete wavefield variation in the apparatus. Numerical simulations of elastic wave propagation, on the other hand, are used to model the wavefield distribution and physical processes in the measurement systems, and to verify the measurement theory and analyze the measurement results. In this paper we provide a numerical simulation method to investigate the acoustic waveform response of the DARS system and the quasi-static responses of the stress-strain system, both of which use axisymmetric apparatus. We applied this method to parameterize the properties of the rock samples, the sample locations and the sensor (hydrophone and strain gauges) locations and simulate the measurement results, i.e. resonance frequencies and axial and radial strains on the sample surface, from the modeled wavefield following the physical experiments. Rock physical parameters were estimated by inversion or direct processing of these data, and showed a perfect match with the true values, thus verifying the validity of the experimental measurements. Error analysis was also conducted for the DARS system with 18 numerical samples, and the sources and levels of error are discussed. In particular, we propose an inversion method for estimating both density and compressibility of these samples. The modeled results also showed fairly good agreement with the real experiment results, justifying the effectiveness and feasibility of our modeling method.

Numerical Study of Frequency-dependent Seismoelectric Coupling in Partially-saturated Porous Media

Directory of Open Access Journals (Sweden)

Djuraev Ulugbek

2017-01-01

Full Text Available The seismoelectric phenomenon associated with propagation of seismic waves in fluid-saturated porous media has been studied for many decades. The method has a great potential to monitor subsurface fluid saturation changes associated with production of hydrocarbons. Frequency of the seismic source has a significant impact on measurement of the seismoelectric effects. In this paper, the effects of seismic wave frequency and water saturation on the seismoelectric response of a partially-saturated porous media is studied numerically. The conversion of seismic wave to electromagnetic wave was modelled by extending the theoretically developed seismoelectric coupling coefficient equation. We assumed constant values of pore radius and zeta-potential of 80 micrometers and 48 microvolts, respectively. Our calculations of the coupling coefficient were conducted at various water saturation values in the frequency range of 10 kHz to 150 kHz. The results show that the seismoelectric coupling is frequency-dependent and decreases exponentially when frequency increases. Similar trend is seen when water saturation is varied at different frequencies. However, when water saturation is less than about 0.6, the effect of frequency is significant. On the other hand, when the water saturation is greater than 0.6, the coupling coefficient shows monotonous trend when water saturation is increased at constant frequency.

Angiotensin-(1-7)/Mas axis modulates fear memory and extinction in mice.

Science.gov (United States)

Lazaroni, Thiago Luiz do Nascimento; Bastos, Cristiane Perácio; Moraes, Márcio Flávio Dutra; Santos, Robson Souza; Pereira, Grace Schenatto

2016-01-01

Inappropriate defense-alerting reaction to fear is a common feature of neuropsychiatric diseases. Therefore, impairments in brain circuits, as well as in molecular pathways underlying the neurovegetative adjustments to fear may play an essential role on developing neuropsychiatric disorders. Here we tested the hypothesis that interfering with angiotensin-(1-7) [Ang-(1-7)]/Mas receptor axis homeostasis, which appears to be essential to arterial pressure control, would affect fear memory and extinction. Mas knockout (MasKO) mice, in FVB/N background, showed normal cued fear memory and extinction, but increased freezing in response to context. Next, as FVB/N has poor performance in contextual fear memory, we tested MasKO in mixed 129xC57BL/6 background. MasKO mice behaved similarly to wild-type (WT), but memory extinction was slower in contextual fear conditioning to a weak protocol (1CS/US). In addition, delayed extinction in MasKO mice was even more pronounced after a stronger protocol (3CS/US). We showed previously that Angiotensin II receptor AT1 antagonist, losantan, rescued object recognition memory deficit in MasKO mice. Here, losartan was also effective. Memory extinction was accelerated in MasKO mice after treatment with losartan. In conclusion, we showed for the first time that Ang-(1-7)/Mas axis may modulate fear memory extinction. Furthermore, we suggest MasKO mice as an animal model to study post-traumatic stress disorder (PTSD). Copyright © 2015 Elsevier Inc. All rights reserved.

Numerical Determination of Natural Frequencies and Modes of the Vibrations of a Thick-Walled Cylindrical Shell

Science.gov (United States)

Grigorenko, A. Ya.; Borisenko, M. Yu.; Boichuk, E. V.; Prigoda, A. P.

2018-01-01

The dynamic characteristics of a thick-walled cylindrical shell are determined numerically using the finite-element method implemented with licensed FEMAR software. The natural frequencies and modes are compared with those obtained earlier experimentally by the method of stroboscopic holographic interferometry. Frequency coefficients demonstrating how the natural frequency depends on the physical and mechanical parameters of the material are determined.

31P Solid-state MAS NMR spectra

International Nuclear Information System (INIS)

Grobet, P.J.; Geerts, H.; Martens, J.A.; Jacobs, P.A.

1989-01-01

The structures of the silicoaluminiophosphates MCM-1 and MCM9 were characterized by 27 Al and 31 P MAS NMR. The structural identity of MCM-1 and its silicon-free homologue AlPO 4 -H 3 is demonstrated. The presence of a structural mixture in MCM-9 is confirmed. 31 P MAS NMR spectra of MCM-9 could be interpreted as a superposition of spectra of VPI-5, AlPO 4 -H 3 and SAPO-11 phases. (author). 12 refs.; 3 figs.; 1 tab

ERP sistēmas ieviešana

OpenAIRE

Proskurins, Aleksandrs

2008-01-01

Šajā darbā tika apskatīta informācijas sistēmu klasifikācija, uzņēmuma resursu plānošanas sistēmas (ERP) definīcija un tās vieta IS klasifikācijā. Tika apskatīti ERP sistēmu ieviešanas teorētiskie aspekti, izstrādes un pielāgošanas specifika, kā arī tika izanalizēti vairāki ERP sistēmas ieviešanas projekti Latvijas uzņēmumos.

Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy

International Nuclear Information System (INIS)

Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

2015-01-01

Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110–120 kHz), 1 H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong 1 H– 1 H homonuclear dipolar couplings and narrow 1 H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) 1 H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about 1 H– 1 H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical

PROPAGANDA POLITIK PARTAI GERINDRA DALAM GAME MAS GARUDA PADA PEMILU 2014 (Analisis Deskriptif Game Online Mas Garuda

Directory of Open Access Journals (Sweden)

Angga Satrya Putra

2016-03-01

Full Text Available The purpose of this study was to determine how the meaning of the look and content of the online game “Garuda Mas”. This game contains aspects of politically charged designations so that it can become a propaganda technique. The subject of this study is the game “Garuda Mas” which has been input on social media Facebook.Methods of data collection using documentary and literature. Data analysis using descriptive techniques. Data validity checking techniques using triangulation source.The results showed that the game “MAS GARUDA” can form the perspective of the players against Mas Garuda as a superhero figure hopes the Indonesian people who are able to overcome all the problems that exist in Indonesia. This game is a form of creative campaigns using propaganda techniques inserted in the game that has the power to change the mindset of every player. Change of mindset occurs because the player did not have an opportunity to think critically on aspects marking contained in the game. By indirectly the players will feel the emotional of this game and assume characterizations “Garuda Mas” in this game is a truth that can be believed.Keywords: Descriptive, Online Games, Mas Garuda, Partai Gerindra

A software framework for analysing solid-state MAS NMR data

International Nuclear Information System (INIS)

Stevens, Tim J.; Fogh, Rasmus H.; Boucher, Wayne; Higman, Victoria A.; Eisenmenger, Frank; Bardiaux, Benjamin; Rossum, Barth-Jan van; Oschkinat, Hartmut; Laue, Ernest D.

2011-01-01

Solid-state magic-angle-spinning (MAS) NMR of proteins has undergone many rapid methodological developments in recent years, enabling detailed studies of protein structure, function and dynamics. Software development, however, has not kept pace with these advances and data analysis is mostly performed using tools developed for solution NMR which do not directly address solid-state specific issues. Here we present additions to the CcpNmr Analysis software package which enable easier identification of spinning side bands, straightforward analysis of double quantum spectra, automatic consideration of non-uniform labelling schemes, as well as extension of other existing features to the needs of solid-state MAS data. To underpin this, we have updated and extended the CCPN data model and experiment descriptions to include transfer types and nomenclature appropriate for solid-state NMR experiments, as well as a set of experiment prototypes covering the experiments commonly employed by solid-sate MAS protein NMR spectroscopists. This work not only improves solid-state MAS NMR data analysis but provides a platform for anyone who uses the CCPN data model for programming, data transfer, or data archival involving solid-state MAS NMR data.

Multinuclear MAS NMR studies on coked zeolites H-ZSM-5

International Nuclear Information System (INIS)

Ernst, H.; Freude, D.; Hunger, M.; Pfeifer, H.

1991-01-01

During the cracking process carbonaceous materials are deposited on the outer or inner surface of the catalyst. These deposits are in many cases the main cause of catalyst deactivation. Magic angle spinning (MAS) NMR investigations and catalytic n-hexane cracking were carried out on H-ZSM-5 zeolites after a mild hydrothermal de-alumination. By 13 C CP MAS NMR it could be shown that the enhanced catalytic activity does not enhance the coke formation and that the chemical nature of these deposits is essentially aromatic. From 1 H MAS NMR studies performed on shallow-bed activated sealed samples and 27 Al and 29 Si MAS NMR on rehydrated samples it follows that for high coke concentrations the catalyst deactivation is caused mainly by blocking of Broensted acid sites. (author). 27 refs.; 3 figs.; 2 tabs

Autolīzinga kompānijas AS "mogo" reklāmas kampaņu izstrāde, izmantojot Facebook reklāmas rīkus

OpenAIRE

Ābeltiņš, Elvis

2017-01-01

Diplomdarba tēma ir “Autolīzinga kompānijas AS “mogo” reklāmas kampaņu izstrāde, izmantojot Facebook reklāmas rīkus”. Vadošais sociālais tīkls Facebook nodrošina plašas reklāmas izvietošanas iespējas un tā auditorijas apjoms ir sasniedzis tradicionālajiem medijiem līdzvērtīgu izmēru. Darba analītiskajā daļā tiek kategorizētas digitālā mārketinga metodes, kā arī apkopota sociālo tīklu lietotāju statistika Latvijā un pasaulē. Projekta daļā autors salīdzina un analizē Facebook reklāmas izvietoša...

KINERJA USAHA TANAMAN HIAS POTONG PT PESONA DAUN MAS ASRI

Directory of Open Access Journals (Sweden)

Muhamad Arief Bangun Sanjaya

2017-01-01

Full Text Available Pesona Daun Mas Asri is a company in cut flowers  and leaves cultivation. The  achievement is shown by the performance of the company. The overall company’s performance contributes in developing the company’s vision. Balanced score card is a management tool used to observe and maintain the stability between financial indicators (financial perspective and non financial indicators (customer, business internal process, growth and learning.  The objective of the journal is to plan the performance of the company using balanced scorecard approach, analyze and calculate the vision, mission and strategy implemented by Pesona Daun Mas in it business activity..  The result for every strategic target shows that the performance of Pesona Daun Mas is excellent with the achieved score of 78,04%.  However the target for the selling growth level and marketing activities are classified as average which means that it still needs to be developed.   Keywords:  balanced scorecard, performance evaluation, KPI performance index, ornamental plants cutAbstrakPesona Daun Mas Asri merupakan perusahaan yang bergerak dalam bidang budi daya bunga potong dan daun potong. Pencapaian dalam menjalankan sebuah perusahaan dapat dilihat dari kinerja perusahaan tersebut.Kinerja perusahaan Pesona Daun Mas Asri secara keseluruhan dapat berkontribusi untuk mengembangkan perusahaan dalam mencapai visi. Balanced scorecard adalah salah satu alat manajemen yang dapat melihat dan menjaga keseimbangan antara indikator keuangan (perspektif keuangan dan indikator non-keuangan (pelanggan, proses bisnisinternal, pertumbuhan dan pembelajaran. Tujuan dari jurnal ini adalah untuk merancang pengukuran kinerja perusahaan dengan pendekatan Balanced scorecard. Penelitian ini juga bertujuan menganalisis dan mengukur pelaksanaan visi, misi dan strategi yang dijalankan oleh Pesona Daun Mas Asri dalam kegiatan bisnisnya. Selain itu, memberikan saran dan rekomendasi, serta merumuskan implikasi

MAS2-8 radar and digital control unit

Science.gov (United States)

Oberg, J. M.; Ulaby, F. T.

1974-01-01

The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented.

Analytical and numerical study of a gaseous plasma dipole in the UHF frequency band

NARCIS (Netherlands)

Melazzi, Davide; Lancellotti, Vito; Capobianco, Antonio Daniele

2017-01-01

Gaseous plasma antennas are appealing in applications in which reconfigurability is desired, because the radiation properties can be changed by tuning the plasma parameters. In this paper, an analytical and numerical analysis of a gaseous plasma dipole that works in the 0.3-3 GHz frequency range is

E/Z MAS: An easy-to-use computerized materials control and accountability system

International Nuclear Information System (INIS)

Anderson, L.K.; Boor, M.G.; Hurford, J.M.; Landry, R.P.; Martinez, B.J.; Solem, A.M.; Whiteson, R.; Zardecki, A.

1998-01-01

Nuclear facilities that handle and process nuclear materials are required to track their nuclear holdings and to keep adequate records that manage and control the inventory of those holdings. The complexity of a system that does this job is directly proportional to the complexity of the facility's operations. This paper describes an approach to computerized materials protection, control, and accountability (MPC and A) that was introduced by Los Alamos National Laboratory (LANL) in the fall of 1997. This new system, E/Z MAS, is the latest addition to the LANL suite of computerized MPC and A tools, which also includes the CoreMAS system. E/Z MAS was initially designed to address the needs of those facilities that have small to modest MPC and A needs but has been expanded to provide full functionality for any facility. The system name, E/Z MAS, reflects the system's easy-to-use characteristics, which include ease of installation and ease of software maintenance. Both CoreMAS and E/Z MAS have been provided to facilities in the Former Soviet Union to assist them in implementing a computerized MPC and A system that meets their needs. In this paper the authors will address the functionality of CoreMAS and E/Z MAS, and an argument in favor of intranet-based material control and accountability will be advanced

Experimental and Numerical Investigation of Thermoacoustic Sources Related to High-Frequency Instabilities

Directory of Open Access Journals (Sweden)

Mathieu Zellhuber

2014-03-01

Full Text Available Flame dynamics related to high-frequency instabilities in gas turbine combustors are investigated using experimental observations and numerical simulations. Two different combustor types are studied, a premix swirl combustor (experiment and a generic reheat combustor (simulation. In both cases, a very similar dynamic behaviour of the reaction zone is observed, with the appearance of transverse displacement and coherent flame wrinkling. From these observations, a model for the thermoacoustic feedback linked to transverse modes is proposed. The model splits heat release rate fluctuations into distinct contributions that are related to flame displacement and variations of the mass burning rate. The decomposition procedure is applied on the numerical data and successfully verified by comparing a reconstructed Rayleigh index with the directly computed value. It thus allows to quantify the relative importance of various feedback mechanisms for a given setup.

Des schémas équivalents pour les circuits couplés multi-enroulements

Science.gov (United States)

Keradec, J. P.; Cogitore, B.; Laveuve, E.; Bensoam, M.

1994-04-01

The aim of this paper is to represent the electrical behaviour of any number of magnetically coupled windings with couplers and inductors. Two methods, mathematicaly justified, are proposed. The second one introduces only positive inductances. As an exemple, it is applied to the representation of a three column three phase transformer. The obtained circuits supply the requisite guide to design more complete circuits which allow the high frequency behaviour of wound components to be taken into account, especialy in electronics simulation softwares. Le but de cet article est de traduire le comportement électrique d'un nombre quelconque d'enroulements magnétiquement couplés, par des coupleurs et des inductances. Deux méthodes, établies mathématiquement, sont proposées. La seconde n'introduit que des inductances positives. A titre d'exemple, elle est appliquée à la représentation d'un transformateur triphasé à trois colonnes. Les schémas obtenus fournissent l'indispensable ossature de schémas plus complets, aptes à représenter le comportement haute fréquence des composants bobinés, notamment dans un logiciel de simulation électronique.

Residue specific hydration of primary cell wall potato pectin identified by solid-state 13C single-pulse MAS and CP/MAS NMR spectroscopy

DEFF Research Database (Denmark)

Larsen, Flemming Hofmann; Chrestensen, Inge Byg; Damager, Iben

2011-01-01

Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by 13C single-pulse (SP) magic-angle-spinning (MAS) and 13C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by 2H SP/MAS NMR experiments. The study shows that the arabinan side chains...... hydrate more readily than the galactan side chains and suggests that the overall hydration properties can be controlled by modifying the ratio of these side chains. Enzymatic modification of native (NA) RG-I provided samples with reduced content of arabinan (sample DA), galactan (sample DG), or both side...... chains (sample DB). Results of these samples suggested that hydration properties were determined by the length and character of the side chains. NA and DA exhibited similar hydration characteristics, whereas DG and DB were difficult to hydrate because of the less hydrophilic properties of the rhamnose...

A General Protocol for Temperature Calibration of MAS NMR Probes at Arbitrary Spinning Speeds

Science.gov (United States)

Guan, Xudong; Stark, Ruth E.

2010-01-01

A protocol using 207Pb NMR of solid lead nitrate was developed to determine the temperature of magic-angle spinning (MAS) NMR probes over a range of nominal set temperatures and spinning speeds. Using BioMAS and fastMAS probes with typical sample spinning rates of 8 and 35 kHz, respectively, empirical equations were devised to predict the respective sample temperatures. These procedures provide a straightforward recipe for temperature calibration of any MAS probe. PMID:21036557

Angiotensin-(1-7)/Mas axis integrity is required for the expression of object recognition memory.

Science.gov (United States)

Lazaroni, Thiago L N; Raslan, Ana Cláudia S; Fontes, Walkiria R P; de Oliveira, Marilene L; Bader, Michael; Alenina, Natalia; Moraes, Márcio F D; Dos Santos, Robson A; Pereira, Grace S

2012-01-01

It has been shown that the brain has its own intrinsic renin-angiotensin system (RAS) and angiotensin-(1-7) (Ang-(1-7)) is particularly interesting, because it appears to counterbalance most of the Ang II effects. Ang-(1-7) exerts its biological function through activation of the G-protein-coupled receptor Mas. Interestingly, hippocampus is one of the regions with higher expression of Mas. However, the role of Ang-(1-7)/Mas axis in hippocampus-dependent memories is still poorly understood. Here we demonstrated that Mas ablation, as well as the blockade of Mas in the CA1-hippocampus, impaired object recognition memory (ORM). We also demonstrated that the blockade of Ang II receptors AT1, but not AT2, recovers ORM impairment of Mas-deficient mice. Considering that high concentrations of Ang-(1-7) may activate AT1 receptors, nonspecifically, we evaluate the levels of Ang-(1-7) and its main precursors Ang I and Ang II in the hippocampus of Mas-deficient mice. The Ang I and Ang II levels are unaltered in the whole hipocampus of MasKo. However, Ang-(1-7) concentration is increased in the whole hippocampus of MasKo mice, as well as in the CA1 area. Taken together, our findings suggest that the functionality of the Ang-(1-7)/Mas axis is essential for normal ORM processing. Copyright © 2011 Elsevier Inc. All rights reserved.

The ACE-2/Ang1-7/Mas cascade enhances bone structure and metabolism following angiotensin-II type 1 receptor blockade.

Science.gov (United States)

Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

2017-07-15

The renin angiotensin system (RAS) regulates numerous systemic functions and is expressed locally in skeletal tissues. Angiotensin1-7 (Ang1-7) is a beneficial member of the RAS, and the therapeutic effects of a large number of angiotensin receptors blockers (ARBs) are mediated by an Ang1-7-dependent cascade. This study examines whether the reported osteo-preservative effects of losartan are mediated through the angiotensin converting enzyme2 (ACE-2)/Ang1-7/Mas pathway in ovariectomized (OVX) rats. Sham and OVX animals received losartan (10mg/kg/d p.o.) for 6 weeks. A specific Mas receptor blocker (A-779) was delivered via mini-osmotic pumps during the losartan treatment period. Serum and urine bone metabolism biomarker levels were measured. Bone trabecular and cortical morphometry were quantified in distal femurs, whereas mineral contents were estimated in ashed bones, serum and urine. Finally, the expression of RAS components, the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) was determined. Losartan significantly improved the elevated bone metabolism marker levels and altered trabecular and cortical structures in OVX animals, and restored normal urinary and skeletal mineral levels. Mas receptor inhibition significantly abolished all osteo-protective effects of losartan and enhanced the deleterious effects of OVX. Losartan enhanced OVX-induced up-regulation of ACE-1, AngII, angiotensin type 1 (AT 1 ) receptor and RANKL expression, and increased ACE-2, Ang1-7, Mas and OPG expression in OVX animals. However, A-779 significantly eradicated the effects of losartan on RAS components and RANKL/OPG expression. Thus, Ang1-7 are involved in the osteo-preservative effects of losartan via Mas receptor, which may add therapeutic value to this well-known antihypertensive agent. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical optimization of quasi-optical mode converter for frequency step-tunable gyrotron

International Nuclear Information System (INIS)

Drumm, O.

2002-08-01

This work concentrates on the design of a quasi-optical mode converter for a frequency step-tunable gyrotron. Special attention is paid to the optimization of the conversion and forming of the exited wave of different frequencies inside the resonator. The investigations were part of the HGF-strategy-fonds-project ''Optimization of Tokamak Operation with controlled ECRH-Deposition''. In the resonator of the gyrotron modes can be exited at frequencies between 105 and 140 GHz. With the designed converter the desired field distribution at the output window for all frequencies will be approximately obtained. The newly gained knowledge and invented synthesis methods are applied to this practical example and verified. In this work, the waveguide antenna and the mirror system of the quasi-optical mode converter are presented separately from each other. At the beginning the synthesis of the aperture antenna for a frequency step-tunable design of the Vlasov-type as well as the Denisov-type is considered. As a conclusion of the investigation, the important parameters for the design of all antennas are summarized and the frequency behavior is compared. In the second part of this work new broadband design methods for the synthesis of the mirror surface are presented. These mirrors make an optimal wave forming for all frequencies equally possible. Therefore new quality criteria are introduced for the broadband evaluation of the mirror. Afterwards the surface is varied until the criteria reach an optimum. For the numerical optimization, in this work the gradient method and the extended Katsenelenbaum-Semenov algorithm are invented and applied. The efficient realization of the described algorithms on a computer is the significant point. The theoretical background of the presented methods for the synthesis of a mirror system is based on the general solution of the Helmholtz equation. Due to this, these methods can be utilized in other fields outside the microwave applications in

Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

Science.gov (United States)

Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

2017-06-01

The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

Modified Ashworth scale and spasm frequency score in spinal cord injury

DEFF Research Database (Denmark)

Baunsgaard, C. B.; Nissen, U. V.; Christensen, K. B.

2016-01-01

.94 and inter-rater κweighted=0.93. Correlation between MAS and SFS showed non-significant correlation coefficients from-0.11 to 0.90. CONCLUSION: Reliability of MAS is highly affected by the weighting scheme. With a weighted-κ it was overall reliable and simple-κ overall unreliability. Repeated tests should......STUDY DESIGN: Intra- and inter-rater reliability study. OBJECTIVES: To assess intra- and inter-rater reliability of the Modified Ashworth Scale (MAS) and Spasm Frequency Score (SFS) in lower extremities in a population of spinal cord-injured persons, as well as correlations between the two scales....... SETTING: Clinic for Spinal Cord Injuries, Rigshospitalet, Hornbaek, Denmark. METHODS: Thirty-one persons participated in the study and were tested four times in total with MAS and SFS by three experienced raters. Cohen's kappa (κ), simple and quadratic weighted (nominal and ordinal scale level...

Neuroprotective Mechanisms of the ACE2-Angiotensin-(1-7)-Mas Axis in Stroke

DEFF Research Database (Denmark)

Bennion, Douglas M; Haltigan, Emily; Regenhardt, Robert W

2015-01-01

The discovery of beneficial neuroprotective effects of the angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis [ACE2-Ang-(1-7)-Mas] in ischemic and hemorrhagic stroke has spurred interest in a more complete characterization of its mechanisms of action. Here, we summarize findings that desc......The discovery of beneficial neuroprotective effects of the angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis [ACE2-Ang-(1-7)-Mas] in ischemic and hemorrhagic stroke has spurred interest in a more complete characterization of its mechanisms of action. Here, we summarize findings...... that describe the protective role of the ACE2-Ang-(1-7)-Mas axis in stroke, along with a focused discussion on the potential mechanisms of neuroprotective effects of Ang-(1-7) in stroke. The latter incorporates evidence describing the actions of Ang-(1-7) to counter the deleterious effects of angiotensin II...... complete understanding of the mechanisms of action of Ang-(1-7) to elicit neuroprotection will serve as an essential step toward research into potential targeted therapeutics in the clinical setting....

The evolution of the MasAgro hubs

NARCIS (Netherlands)

Camacho-Villa, Tania Carolina; Almekinders, Conny; Hellin, Jon; Martinez-Cruz, Tania Eulalia; Rendon-Medel, Roberto; Guevara-Hernández, Francisco; Beuchelt, Tina D.; Govaerts, Bram

2016-01-01

Purpose: Little is known about effective ways to operationalize agricultural innovation processes. We use the MasAgro program in Mexico (which aims to increase maize and wheat productivity, profitability and sustainability), and the experiences of middle level ‘hub managers’, to understand how

Low dose multi-detector CT of the chest (iLEAD Study): Visual ranking of different simulated mAs levels

International Nuclear Information System (INIS)

Ley-Zaporozhan, Julia; Ley, Sebastian; Krummenauer, Frank; Ohno, Yoshiharu; Hatabu, Hiroto; Kauczor, Hans-Ulrich

2010-01-01

Purpose: Detailed evaluation of the lung parenchyma might be impaired by use of low dose CT as image noise increases and subsequently image quality decreases. The aim of our study was to determine the accuracy of visual perception of differences in image quality and noise at low dose chest CT. Materials and methods: Forty-four patients suffering from emphysema underwent CT (Aquilion-16, 120 kV, 150 mAs, 1 mm-collimation). Original raw data were used for simulation of 10 different mAs settings from 10 mAs to 100 mAs in 10 mAs increments. Three representative hard copy images (carina, 4 cm above, 5 cm below) were printed for evaluation of lung parenchyma (high-resolution kernel, lung window) and mediastinum (soft-kernel, soft tissue window). Ranking of expected low mAs level was performed for lung and soft tissue separately based on visual perception by three-blinded chest radiologist independently. Results were compared to the real simulated mAs. Results: The accuracy for correct ranking of the original 150 mAs scan was 89% for lung and 86% for soft tissue while it was 99% for the simulated 10 mAs for both windows. In comparison to the lowest mAs a significant error increase was found for the lung at 60-100 mAs (with error increase of 30-47%) for reader-I; 60-100 mAs for (33-64%) for reader-II and 70-100 mAs (38-57%) for reader-III. For the soft tissue: 60-150 mAs (with error increase of 28-63%) for reader-I; 50-100 mAs (35-56%) for reader-II and 50-90 mAs (35-40%) for reader-III. Conclusion: Simulated dose levels below 60 mAs (=42 mAs eff ) were clearly differentiated from higher dose levels by all readers. Therefore, imaging doses could be lowered down to 60 mAs without a diagnostically relevant increase in noise impairing image quality.

Numerical modelisation of RF waves in the ion cyclotron range of frequency for Tokamak plasmas

International Nuclear Information System (INIS)

Edery, D.; Picq, H.; Samain, A.; Gambier, D.J.

1987-12-01

The purpose of this paper is to present the numerical code ALCYON developed to compute the RF field structure in the ion cyclotron range of frequencies. The code handles fundamental and second harmonic heating while the mode conversion onto modes of decreasing wavelength is simulated by a selective power absorption on slow waves when their wavelength reaches the mesh size

Numerical simulation of minor actinide recovery behaviour in batch processing of spent metallic fuel by electrorefining

Energy Technology Data Exchange (ETDEWEB)

Nawada, H P; Bhat, N P [Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Balasubramanian, G R [Atomic Energy Commission, Mumbai (India)

1994-06-01

Numerical simulation of electro-transport of fuel actinides (FAs), minor actinides (MAs) and rare earths (REs) in the electro-refiner (ER) for pyrochemical reprocessing of a typical spent IFR metallic fuel has been attempted based on improved thermo-chemical model developed for application to multi-component system in the ER. Optimization of MA recovery and decontamination factors (DFs) for MAs and REs in batch processing is presented. (author). 7 refs., 4 figs., 1 tab.

SecMAS: Security Enhanced Monitoring and Analysis Systems for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Ding Chao

2016-01-01

Full Text Available The monitoring, control, and security guarantee for the communication in the wireless sensor networks (WSNs are currently treated as three independent issues and addressed separately through specialized tools. However, most cases of WSNs applications requires the network administrator change the network configuration in a very short time to response to the change of observed phenomenon with security guarantee. To meet this requirement, we propose a security enhanced monitoring and control platform named SecMAS for WSNs, which provides the real-time visualization about network states and online reconfiguration of the network properties and behaviours in a resource-efficient way. Besides, basic cryptographic primitives and part of the anomaly detection functionalities are implemented in SecMAS to enabling the secure communication in WSNs. Furthermore, we conduct experiments to evaluate the performance of SecMAS in terms of the latency, throughput, communication overhead, and the security capacity. The experimental results demonstrate that the SecMAS system achieves stable, efficient and secure data collection with lightweight quick-response network control.

Numerical investigation into the injection-locking phenomena of gain switched lasers for optical frequency comb generation

International Nuclear Information System (INIS)

Ó Dúill, Sean P.; Anandarajah, Prince M.; Zhou, Rui; Barry, Liam P.

2015-01-01

We present detailed numerical simulations of the laser dynamics that describe optical frequency comb formation by injection-locking a gain-switched laser. The typical rate equations for semiconductor lasers including stochastic carrier recombination and spontaneous emission suffice to show the injection-locking behavior of gain switched lasers, and we show how the optical frequency comb evolves starting from the free-running state, right through the final injection-locked state. Unlike the locking of continuous wave lasers, we show that the locking range for gain switched lasers is considerably greater because injection locking can be achieved by injecting at frequencies close to one of the comb lines. The quality of the comb lines is formally assessed by calculating the frequency modulation (FM)-noise spectral density and we show that under injection-locking conditions the FM-noise spectral density of the comb lines tend to that of the maser laser

Numerical investigation into the injection-locking phenomena of gain switched lasers for optical frequency comb generation

Energy Technology Data Exchange (ETDEWEB)

Ó Dúill, Sean P., E-mail: sean.oduill@dcu.ie; Anandarajah, Prince M.; Zhou, Rui; Barry, Liam P. [The RINCE Institute, Dublin City University, Glasnevin, Dublin 9 (Ireland)

2015-05-25

We present detailed numerical simulations of the laser dynamics that describe optical frequency comb formation by injection-locking a gain-switched laser. The typical rate equations for semiconductor lasers including stochastic carrier recombination and spontaneous emission suffice to show the injection-locking behavior of gain switched lasers, and we show how the optical frequency comb evolves starting from the free-running state, right through the final injection-locked state. Unlike the locking of continuous wave lasers, we show that the locking range for gain switched lasers is considerably greater because injection locking can be achieved by injecting at frequencies close to one of the comb lines. The quality of the comb lines is formally assessed by calculating the frequency modulation (FM)-noise spectral density and we show that under injection-locking conditions the FM-noise spectral density of the comb lines tend to that of the maser laser.

KrasMAS: Implementation of a nuclear material computerized accounting system at the Mining and Chemical Combine through the Russian/US cooperative MPC and A program

International Nuclear Information System (INIS)

Dorofeev, K.V.; Zhidkov, V.V.; Martinez, B.J.; Perry, R.T.; Scott, S.C.

1998-01-01

The Russian/US Mining and Chemical Combine (Gorno-Kimichesky Kombinat, GKhK, also referred to as Krasnoyarsk-26) Material Protection, Control and Accounting (MPC and A) project was initiated in June 1996. A critical component of the ongoing cooperative MPC and A enhancements at the GKhK is the implementation of a computerized nuclear material control and accountability (MC and A) system. This system must meet the MC and A requirements of the GKhK by integrating the information generated by numerous existing and new MC and A components in place at the GKhK (e.g., scales, bar-code equipment, NDA measurement systems). During the first phase of this effort, the GKhK adapted CoreMAS (developed at Los Alamos National Laboratory) for use in the PuO 2 storage facility. This included formulation of Web-based user interfaces for plant personnel, Russification of the existing user interface, and at the functional level, modification of the CoreMAS stored procedures. The modified system is referred to as KrasMAS and builds upon completed work on CoreMAS. Ongoing efforts include adding GKhK specific report forms and expanding the functionality of the system for implementation at the radiochemical processing and reactor plants of the GKhK. Collaborations with other Russian facilities for appropriate parts of these efforts will be pursued

Numerical Simulation of Spheroidization Process of TiAl Alloy Powders in Radio Frequency Plasma

OpenAIRE

ZHU Langping; LU Xin; LIU Chengcheng; LI Jianchong; NAN Hai

2017-01-01

A numerical simulation method was used to study the radio frequency plasma spheroidization process of TiAl alloy powder. The effects of velocity field and temperature field on the motion trajectory and mass change of TiAl alloy powder with different particle size were analyzed.The results show that the temperature of powder particles increases rapidly under high temperature plasma, surface evaporation cause the reduction of particle size, and particles with small size tend to evaporate quickl...

HUBUNGAN ANTARA PERTUMBUHAN DENGAN KEBERADAAN GEN TAHAN PENYAKIT MAJOR HISTOCOMPATIBILITY COMPLEX (MHC PADA IKAN MAS (Cyprinus carpio

Directory of Open Access Journals (Sweden)

Erma Primanita Hayuningtyas

2016-04-01

Full Text Available Wabah penyakit koi herpes virus (KHV di Indonesia yang terjadi sejak tahun 2002 merupakan salah satu faktor yang memicu kemerosotan produksi ikan mas budidaya. Pembentukan strain unggul ikan mas tahan KHV dapat menjadi solusi bagi permasalahan tersebut. Pemilihan genotip ikan mas tahan KHV dengan marka molekuler gen major histocompatibility complex class II (MHC-II, khususnya pada alel Cyca DAB 1*05 akan membantu dalam kegiatan seleksi. Penelitian ini bertujuan untuk mengetahui keberadaan gen MHC-II pada populasi dasar G0 ikan mas strain Rajadanu dan hubungannya dengan pertumbuhan (bobot. Metode deteksi keberadaan gen MHC-II pada dua kelompok ikan dengan ukuran berbeda dilakukan dengan teknik PCR. Hubungan antara pertumbuhan ikan mas dengan persentase kemunculan gen MHC-II dianalisis dengan menggunakan program SPSS (Statistical Package for the Social Sciences, sehingga diperoleh korelasi di antara keduanya. Hasil penelitian menunjukkan bahwa hubungan antara pertumbuhan dengan persentase keberadaan gen MHC-II berkorelasi negatif dengan nilai R = -0,742. Hal ini mengindikasikan bahwa semakin cepat pertumbuhan populasi ikan mas maka semakin sedikit persentase individu yang mempunyai gen MHC-II pada setiap populasi ikan mas. Sehingga populasi ikan mas yang pertumbuhannya lambat memiliki tingkat persentase positif MHC-II lebih tinggi (85,71%-100% dibandingkan populasi ikan mas yang pertumbuhannya cepat (42,86%-85,71%.

Numerical analysis of effects of transglottal pressure change on fundamental frequency of phonation.

Science.gov (United States)

Deguchi, Shinji; Matsuzaki, Yuji; Ikeda, Tadashige

2007-02-01

In humans, a decrease in transglottal pressure (Pt) causes an increase in the fundamental frequency of phonation (F0) only at a specific voice pitch within the modal register, the mechanism of which remains unclear. In the present study, numerical analyses were performed to investigate the mechanism of the voice pitch-dependent positive change of F0 due to Pt decrease. The airflow and the airway, including the vocal folds, were modeled in terms of mechanics of fluid and structure. Simulations of phonation using the numerical model indicated that Pt affects both the average position and the average amplitude magnitude of vocal fold self-excited oscillation in a non-monotonous manner. This effect results in voice pitch-dependent responses of F0 to Pt decreases, including the positive response of F0 as actually observed in humans. The findings of the present study highlight the importance of considering self-excited oscillation of the vocal folds in elucidation of the phonation mechanism.

Numerical simulation of seismic low-frequency shadows and its application%地震低频伴影的数值模拟与应用

Institute of Scientific and Technical Information of China (English)

贺振华; 熊晓军; 边立恩

2008-01-01

Strong low-frequency energy beneath a hydrocarbon reservoir is called a seismic low-frequency shadow and can be used as a hydrocarbon indicator (Taner et al., 1979) but the physical mechanism of the observed low-frequency shadow is still unclear. To study the mechanism, we performed seismic numerical simulation of geological models with a hydrocarbon-bearing zone using the 2-D diffusive-viscous wave equation which can effectively model the characteristics of velocity dispersion and transform the seismic data centered in a target layer slice within a time window to the time-frequency domain by using time-frequency signal analysis and sort the frequency gathers to common frequency cubes. Then, we observe the characteristics of the seismic low-frequency shadow in the common frequency cubes. The numerical simulations reveal that the main mechanism of seismic low-frequency shadows is attributed to high attenuation of the medium to high seismic frequency components caused by absorption in the hydrocarbon-filled reservoir. Results from a practical example of seismic low-frequency shadows show that it is possible to identify the reservoir by the low-frequency shadow with high S/N seismic data.

Numerical Investigation and Experimental Demonstration of Chaos from Two-Stage Colpitts Oscillator in the Ultrahigh Frequency Range

DEFF Research Database (Denmark)

Bumeliene, S.; Tamasevicius, A.; Mykolaitis, G.

2006-01-01

A hardware prototype of the two-stage Colpitts oscillator employing the microwave BFG520 type transistors with the threshold frequency of 9 GHz and designed to operate in the ultrahigh frequency range (300–1000 MHz) is described. The practical circuit in addition to the intrinsic two-stage oscill......A hardware prototype of the two-stage Colpitts oscillator employing the microwave BFG520 type transistors with the threshold frequency of 9 GHz and designed to operate in the ultrahigh frequency range (300–1000 MHz) is described. The practical circuit in addition to the intrinsic two......-stage oscillator contains an emitter follower acting as a buffer and minimizing the influence of the load. The circuit is investigated both numerically and experimentally. Typical phase portraits, Lyapunov exponents, Lyapunov dimension and broadband continuous power spectra are presented. The main advantage...

Numerical studies of independent control of electron density and gas temperature via nonlinear coupling in dual-frequency atmospheric pressure dielectric barrier discharge plasmas

International Nuclear Information System (INIS)

Zhang, Z. L.; Nie, Q. Y.; Wang, Z. B.; Gao, X. T.; Kong, F. R.; Sun, Y. F.; Jiang, B. H.

2016-01-01

Dielectric barrier discharges (DBDs) provide a promising technology of generating non-equilibrium cold plasmas in atmospheric pressure gases. For both application-focused and fundamental studies, it is important to explore the strategy and the mechanism for enabling effective independent tuning of key plasma parameters in a DBD system. In this paper, we report numerical studies of effects of dual-frequency excitation on atmospheric DBDs, and modulation as well as separate tuning mechanism, with emphasis on dual-frequency coupling to the key plasma parameters and discharge evolution. With an appropriately applied low frequency to the original high frequency, the numerical calculation demonstrates that a strong nonlinear coupling between two frequencies governs the process of ionization and energy deposition into plasma, and thus raises the electron density significantly (e.g., three times in this case) in comparisons with a single frequency driven DBD system. Nevertheless, the gas temperature, which is mainly determined by the high frequency discharge, barely changes. This method then enables a possible approach of controlling both averaged electron density and gas temperature independently.

ACE-2/Ang1-7/Mas cascade mediates ACE inhibitor, captopril, protective effects in estrogen-deficient osteoporotic rats.

Science.gov (United States)

Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

2017-08-01

The local role of the renin angiotensin system (RAS) was documented recently beside its conventional systemic functions. Studies showed that the effector angiotensin II (AngII) alters bone health, while inhibition of the angiotensin converting enzyme (ACE-1) preserved these effects. The newly identified Ang1-7 exerts numerous beneficial effects opposing the AngII. Thus, the current study examines the role of Ang1-7 in mediating the osteo-preservative effects of ACEI (captopril) through the G-protein coupled Mas receptor using an ovariectomized (OVX) rat model of osteoporosis. 8 weeks after the surgical procedures, captopril was administered orally (40mgkg -1 d -1 ), while the specific Mas receptor blocker (A-779) was delivered at infusion rate of 400ngkg -1 min -1 for 6 weeks. Bone metabolic markers were measured in serum and urine. Minerals concentrations were quantified in serum, urine and femoral bones by inductive coupled plasma mass spectroscopy (ICP-MS). Trabecular and cortical morphometry was analyzed in the right distal femurs using micro-CT. Finally, the expressions of RAS peptides, enzymes and receptors along with the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) were determined femurs heads. OVX animals markedly showed altered bone metabolism and mineralization along with disturbed bone micro-structure. Captopril significantly restored the metabolic bone bio-markers and corrected Ca 2+ and P values in urine and bones of estrogen deficient rats. Moreover, the trabecular and cortical morphometric features were repaired by captopril in OVX groups. Captopril also improved the expressions of ACE-2, Ang1-7, Mas and OPG, while abolished OVX-induced up-regulation of ACE-1, AngII, Ang type 1 receptor (AT1R) and RANKL. Inhibition of Ang1-7 cascade by A-779 significantly eradicated captopril protective effects on bone metabolism, mineralization and micro-structure. A-779 also restored OVX effects on RANKL expression and ACE-1/AngII/AT1R

MAS Integration and Controllership Effectiveness: Evidence of a Preparer-User Perception Gap

OpenAIRE

Weißenberger, Barbara E.; Angelkort, Hendrik; Holthoff, Gero

2012-01-01

Recent evidence suggests that managers establish a positive link between management accounting system (MAS) integration and controllership effectiveness, which is fully mediated by the perceived consistency of financial language. Our paper extends this research by analyzing whether controllers have similar perceptions on MAS design. Testing a series of multi-group structural equation models, we find evidence for a preparer-user perception gap with respect to the mediating impact of a consiste...

Numerical simulations of the radio-frequency-driven toroidal current in tokamaks

International Nuclear Information System (INIS)

Peysson, Y.; Decker, J.

2014-01-01

Radio-frequency (rf) waves are a powerful tool for improving the performance and stability of tokamak plasmas through heating and current drive mechanisms, allowing current density profile control and steady-state operation. From first principles, and taking advantage from the ordering between the various time and space scales, fast and powerful numerical tools have been developed to calculate the rf-driven current. The current drive problem in tokamaks is first introduced with the purpose of maintaining a steady-state self-organized toroidal magnetohydrodynamic equilibrium, such that a minimal amount of the fusion power has to be recycled to control the plasma current. The strict criterion that characterizes a steady-state discharge is derived from the response of the tokamak, considered as a transformer, and of the plasma, when an external source of current is applied. The calculation of a rf-driven source of current requires solving self-consistently a set of equations describing the dynamics of wave fields and charged particles in an inhomogeneous magnetized plasma. The range of applicability of these equations is discussed, as well as numerical methods developed to solve them, such as the ray-tracing code C3PO and the three-dimensional linearized relativistic bounce-averaged electron Fokker-Planck solver LUKE. Simulations of current drive by lower-hybrid waves are presented to illustrate the applications of our numerical tools. Current drive modeling includes the effect of electron density fluctuations at the plasma edge, and the case of electron cyclotron waves used for stabilization of the 3/2 neoclassical tearing modes in ITER is studied in detail. Finally, ongoing developments, including cross effects between momentum and configuration spaces, aiming at improving current drive calculations are discussed. (authors)

Improved background suppression in 1H MAS NMR using composite pulses

Science.gov (United States)

Odedra, Smita; Wimperis, Stephen

2012-08-01

A well known feature of 1H MAS NMR spectroscopy, particularly of solids where the concentration of 1H nuclei is low, is the presence in the spectrum of a significant broad "background" signal arising from 1H nuclei that are outside the MAS rotor and radiofrequency coil, probably located on the surfaces of the static components of the probehead. A popular method of suppressing this unwanted signal is the "depth pulse" method, consisting of a 90° pulse followed by one or two 180° pulses that are phase cycled according to the "Exorcycle" scheme, which removes signal associated with imperfect 180° pulses. Consequently, only spins in the centre of the radiofrequency coil contribute to the 1H MAS spectrum, while those experiencing a low B1 field outside the coil are suppressed. Although very effective at removing background signal from the spectrum, one drawback with this approach is that significant loss of the desired signal from the sample also occurs. Here we investigate the 1H background suppression problem and, in particular, the use of novel antisymmetric passband composite pulses to replace the simple pulses in a depth pulse experiment. We show that it is possible to improve the intensity of the 1H signals of interest while still maintaining effective background suppression. We expect that these results will be relevant to 1H MAS NMR studies of, for example, nominally perdeuterated biological samples or nominally anhydrous inorganic materials.

Low-frequency electrostatic waves in the ionospheric E-region: a comparison of rocket observations and numerical simulations

Directory of Open Access Journals (Sweden)

L. Dyrud

2006-11-01

Full Text Available Low frequency electrostatic waves in the lower parts of the ionosphere are studied by a comparison of observations by instrumented rockets and of results from numerical simulations. Particular attention is given to the spectral properties of the waves. On the basis of a good agreement between the observations and the simulations, it can be argued that the most important nonlinear dynamics can be accounted for in a 2-D numerical model, referring to a plane perpendicular to a locally homogeneous magnetic field. It does not seem necessary to take into account turbulent fluctuations or motions in the neutral gas component. The numerical simulations explain the observed strongly intermittent nature of the fluctuations: secondary instabilities develop on the large scale gradients of the largest amplitude waves, and the small scale dynamics is strongly influenced by these secondary instabilities. We compare potential variations obtained at a single position in the numerical simulations with two point potential-difference signals, where the latter is the adequate representation for the data obtained by instrumented rockets. We can demonstrate a significant reduction in the amount of information concerning the plasma turbulence when the latter signal is used for analysis. In particular we show that the bicoherence estimate is strongly affected. The conclusions have implications for studies of low frequency ionospheric fluctuations in the E and F regions by instrumented rockets, and also for other methods relying on difference measurements, using two probes with large separation. The analysis also resolves a long standing controversy concerning the supersonic phase velocities of these cross-field instabilities being observed in laboratory experiments.

Improved background suppression in ¹H MAS NMR using composite pulses.

Science.gov (United States)

Odedra, Smita; Wimperis, Stephen

2012-08-01

A well known feature of ¹H MAS NMR spectroscopy, particularly of solids where the concentration of ¹H nuclei is low, is the presence in the spectrum of a significant broad "background" signal arising from ¹H nuclei that are outside the MAS rotor and radiofrequency coil, probably located on the surfaces of the static components of the probehead. A popular method of suppressing this unwanted signal is the "depth pulse" method, consisting of a 90° pulse followed by one or two 180° pulses that are phase cycled according to the "Exorcycle" scheme, which removes signal associated with imperfect 180° pulses. Consequently, only spins in the centre of the radiofrequency coil contribute to the ¹H MAS spectrum, while those experiencing a low B₁ field outside the coil are suppressed. Although very effective at removing background signal from the spectrum, one drawback with this approach is that significant loss of the desired signal from the sample also occurs. Here we investigate the ¹H background suppression problem and, in particular, the use of novel antisymmetric passband composite pulses to replace the simple pulses in a depth pulse experiment. We show that it is possible to improve the intensity of the ¹H signals of interest while still maintaining effective background suppression. We expect that these results will be relevant to ¹H MAS NMR studies of, for example, nominally perdeuterated biological samples or nominally anhydrous inorganic materials. Copyright © 2012 Elsevier Inc. All rights reserved.

Elektroniskās naudas sistēmas WebMoney

OpenAIRE

Zablocka, Jelena

2011-01-01

Šī darba mērķis ir pamatojoties uz speciālo literatūru un pieejamu statistisko informāciju izskatīt jautājumu par elektroniskās naudas būtību, raksturot un parādīt tās veidus, analizēt un izskatīt elektroniskās naudas izmantošanas problēmas, izpētīt un norādīt tās izmantošanas perspektīvas, novērtēt tās uzskaites un kontroles operāciju problēmas, kas ir sastopamas, izmantojot elektronisko naudu praksē. Darbs sastāv no 5 nodaļām. Pirmajā nodaļā aplūkoti elektroniskās naudas jēdziens un ...

Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer.

Science.gov (United States)

Park, SangWook; Kim, Minhyuk

2016-01-01

In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD) algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the IEEE standard guidelines.

Escala de atitudes frente ao dinheiro (MAS: Teste de modelos e poder preditivo

Directory of Open Access Journals (Sweden)

Carlos Eduardo Pimentel

2012-01-01

Full Text Available The social importance attached to money and its role as an important motivator of behavior justifies the study of its psychosocial aspects. But there is a lack of studies concerning attitudinal or psychological aspects of money in Brazil. In order to encourage research in this context, the validity of the Money Attitudes Scale (MAS was tested using confirmatory factor approaches. Results supported a brief 16-items version of the scale and replicated the factor analytic pattern with satisfactory internal consistency for the factors of power, retention, distrust, and anxiety. Age differences were observed regarding money attitudes of power, and the predictive role of the MAS to account for consumer behavior was also confirmed. This version of the MAS shows evidences of factorial validity and reliability, justifying its use in future research.

High Tech M&As

DEFF Research Database (Denmark)

Toppenberg, Gustav

2013-01-01

Technology driven industries have seen fast moving technology changes, higher complexity and reduced product life cycles. These emerging trends present challenges for companies in industries where technology is at the forefront. The extant research deals with ‘low-tech’ industries and majority...... of findings are not applicable to the high-tech industry; in fact this industry has many additional challenges. In this study, we aim to explore the process of M&A in the high-tech industry by drawing on extant literature and empirical field work. The paper outlines a research project in progress which...... intends to provide theoretical, empirical and practical contributions in answering the research question: what role does Operations and IT play in creating value in high-tech M&As? The research adds a needed perspective on M&A literature by unveiling unique challenges and opportunities faced by the M...

CAMEX-4 ER-2 MODIS AIRBORNE SIMULATOR (MAS) V1

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS Airborne Simulator (MAS) is an airborne scanning spectrometer that acquires high spatial resolution imagery of cloud and surface features from its vantage...

Development of a generic, computerized nuclear material accountability system: NucMAS

International Nuclear Information System (INIS)

Cornell, M.D.; O'Leary, J.M.

1987-01-01

The application NucMAS provides basic computerized accountability functions for the Savannah River Plant (SRP) Separations Department Material Balance Areas (MBA's). These functions include data entry, data management, calculations, and report generation. NucMAS can be used both for routine reporting to the SRP central Material Control and Accounting (MC and A) system and for rapid ad hoc queries in emergency situations. The system is designed to work with any process handling one or more of the 17 accountable nuclear materials specified by the Department of Energy (DOE). It relies on user-supplied configuration data to drive data prompts, report headings, data validations, and calculations

Numerical comparison of improved methods of testing in contingency tables with small frequencies

Energy Technology Data Exchange (ETDEWEB)

Sugiura, Nariaki; Otake, Masanori

1968-11-14

The significance levels of various tests for a general c x k contingency table are usually given by large sample theory. But they are not accurate for the one having small frequencies. In this paper, a numerical evaluation was made to determine how good the approximation of significance level is for various improved tests that have been developed by Nass, Yoshimura, Gart, etc. for c x k contingency table with small frequencies in some of cells. For this purpose we compared the significance levels of the various approximate methods (i) with those of one-sided tail defined in terms of exact probabilities for given marginals in 2 x 2 table; (ii) with those of exact probabilities accumulated in the order of magnitude of Chi/sup 2/ statistic or likelihood ratio (=LR) statistic in 2 x 3 table mentioned by Yates. In 2 x 2 table it is well known that Yates' correction gives satisfactory result for small cell frequencies and the other methods that we have not referred here, can be considered if we devote our attention only to 2 x 2 or 2 x k table. But we are mainly interested in comparing the methods that are applicable to a general c x k table. It appears that such a comparison for the various improved methods in the same example has not been made explicitly, even though these tests are frequently used in biological and medical research. 9 references, 6 figures, 6 tables.

Stochastic reduced-order model for an automotive vehicle in presence of numerous local elastic modes in the low-frequency range

OpenAIRE

Arnoux , A.; Batou , Anas; Soize , Christian; Gagliardini , L.

2012-01-01

International audience; This paper is devoted to the construction of a stochastic reduced-order model for dynamical structures having a high modal density in the low-frequency range, such as an automotive vehicle. This type of structure is characterized by the fact that it exhibits, in the low-frequency range, not only the classical global elastic modes but also numerous local elastic modes which cannot easily be separated from the global elastic modes. An approach has recently been proposed ...

Allelic frequencies and association with carcass traits of six genes in local subpopulations of Japanese Black cattle.

Science.gov (United States)

Nishimaki, Takahiro; Ibi, Takayuki; Siqintuya; Kobayashi, Naohiko; Matsuhashi, Tamako; Akiyama, Takayuki; Yoshida, Emi; Imai, Kazumi; Matsui, Mayu; Uemura, Keiichi; Eto, Hisayoshi; Watanabe, Naoto; Fujita, Tatsuo; Saito, Yosuke; Komatsu, Tomohiko; Hoshiba, Hiroshi; Mannen, Hideyuki; Sasazaki, Shinji; Kunieda, Tetsuo

2016-04-01

Marker-assisted selection (MAS) is expected to accelerate the genetic improvement of Japanese Black cattle. However, verification of the effects of the genes for MAS in different subpopulations is required prior to the application of MAS. In this study, we investigated the allelic frequencies and genotypic effects for carcass traits of six genes, which can be used in MAS, in eight local subpopulations. These genes are SCD, FASN and SREBP1, which are associated with the fatty acid composition of meat, and NCAPG, MC1R and F11, which are associated with carcass weight, coat color and blood coagulation abnormality, respectively. The frequencies of desirable alleles of SCD and FASN were relatively high and that of NCAPG was relatively low, and NCAPG was significantly associated with several carcass traits, including carcass weight. The proportions of genotypic variance explained by NCAPG to phenotypic variance were 4.83 for carcass weight. We thus confirmed that NCAPG is a useful marker for selection of carcass traits in these subpopulations. In addition, we found that the desirable alleles of six genes showed no negative effects on carcass traits. Therefore, selection using these genes to improve target traits should not have negative impacts on carcass traits. © 2015 Japanese Society of Animal Science.

Exposure (mAs) optimisation of a multi-detector CT protocol for hepatic lesion detection: are thinner slices better?

International Nuclear Information System (INIS)

Dobeli, Karen L.; Lewis, Sarah J.; Meikle, Steven R.; Brennan, Patrick C.; Thiele, David L.

2014-01-01

The purpose of this work was to determine the exposure-optimised slice thickness for hepatic lesion detection with CT. A phantom containing spheres (diameter 9.5, 4.8 and 2.4mm) with CT density 10 HU below the background (50 HU) was scanned at 125, 100, 75 and 50 mAs. Data were reconstructed at 5-, 3- and 1-mm slice thicknesses. Noise, contrast-to-noise ratio (CNR), area under the curve (AUC) as calculated using receiver operating characteristic analysis and sensitivity representing lesion detection were calculated and compared. Compared with the 125 mAs/5mm slice thickness setting, significant reductions in AUC were found for 75 mAs (P<0.01) and 50 mAs (P<0.05) at 1- and 3-mm thicknesses, respectively; sensitivity for the 9.5-mm sphere was significantly reduced for 75 (P<0.05) and 50 mAs (P<0.01) at 1-mm thickness; sensitivity for the 4.8-mm sphere was significantly lower for 100, 75 and 50 mAs at all three slice thicknesses (P<0.05). The 2.4-mm sphere was rarely detected. At each slice thickness, noise at 100, 75 and 50 mAs exposures was approximately 10, 30 and 50% higher, respectively, than that at 125 mAs exposure. CNRs decreased in an irregular manner with reductions in exposure and slice thickness. This study demonstrated no advantage to using slices below 5mm thickness, and consequently thinner slices are not necessarily better.

Smoke, Clouds and Radiation Brazil NASA ER-2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS) Data

Data.gov (United States)

National Aeronautics and Space Administration — SCARB_ER2_MAS data are Smoke, Clouds and Radiation Brazil (SCARB) NASA ER2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS)...

Characterization and significance of ACE2 and Mas receptor in human colon adenocarcinoma.

Science.gov (United States)

Bernardi, Stella; Zennaro, Cristina; Palmisano, Silvia; Velkoska, Elena; Sabato, Nicoletta; Toffoli, Barbara; Giacomel, Greta; Buri, Luigi; Zanconati, Fabrizio; Bellini, Giuseppe; Burrell, Louise M; De Manzini, Nicolò; Fabris, Bruno

2012-03-01

A new arm of the renin-angiotensin system (RAS) has been recently characterized; this includes angiotensin converting enzyme (ACE)2 and angiotensin (Ang)1-7, a heptapeptide acting through the Mas receptor (MasR). Recent studies show that Ang1-7 has an antiproliferative action on lung adenocarcinoma cells. The aim of this study was to characterize RAS expression in human colon adenocarcinoma and to investigate whether Ang1-7 exerts an antiproliferative effect on human colon adenocarcinoma cells. Gene, protein expression and enzymatic activity of the main components of the RAS were determined on non-neoplastic colon mucosa as well as on the tumor mass and the mucosa taken 5 cm distant from it, both collected from patients with colon adenocarcinoma. Two different human colon cancer cell lines were treated with AngII and Ang1-7. The novel finding of this study was that MasR was significantly upregulated in colon adenocarcinoma compared with non-neoplastic colon mucosa, which showed little or no expression of it. ACE gene expression and enzymatic activity were also increased in the tumors. However, AngII and Ang1-7 did not have any pro-/antiproliferative effects in the cell lines studied. The data suggest that upregulation of the MasR could be used as a diagnostic marker of colon adenocarcinoma.

Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer.

Directory of Open Access Journals (Sweden)

SangWook Park

Full Text Available In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP and the IEEE standard guidelines.

Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer

Science.gov (United States)

Kim, Minhyuk

2016-01-01

In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD) algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the IEEE standard guidelines. PMID:27898688

Gamma-radiation induced cross-links in ethylene-propylene rubber studied by CP-MAS NMR

International Nuclear Information System (INIS)

Sohma, J.; Shiotani, M.; Murakami, S.

1983-01-01

A new technique of 13 C-NMR, the CP-MAS method, was applied to study a chemistry of cross-links induced by #betta#-irradiation of ethylene-propylene rubber. The chemical species of cross-linking points were specified with their relative concentrations by the analysis of the CP-MAS spectra obtained before and after the irradiation. It was found that the short branches were also formed by the irradiation. A comparison was made between the cross-links detected by the CP-MAS method and those obtained by the Charlesby-Pinner analysis of the gelation caused by the #betta#-irradiation. The conventional 13 C-NMR of the cross-linked and swollen EPR provided us an information on the sol parts of the sample but little information on the cross-links in the gel parts. (author)

Angiotensin II Type 2 Receptor and Receptor Mas Are Colocalized and Functionally Interdependent in Obese Zucker Rat Kidney

DEFF Research Database (Denmark)

Patel, Sanket N; Ali, Quaisar; Samuel, Preethi

2017-01-01

The actions of angiotensin II type 2 receptor (AT2R) and the receptor Mas (MasR) are complex but show similar pronatriuretic function; particularly, AT2R expression and natriuretic function are enhanced in obese/diabetic rat kidney. In light of some reports suggesting a potential positive...... interaction between these receptors, we tested hypothesis that renal AT2R and MasR physically interact and are interdependent to stimulate cell signaling and promote natriuresis in obese rats. We found that infusion of AT2R agonist C21 in obese Zucker rats (OZR) increased urine flow and urinary Na excretion...... coimmunoprecipitated with MasR in cortical homogenate of OZR. Immunoblotting of cortical homogenate cross-linked with zero-length oxidative (sulfhydryl groups) cross-linker cupric-phenanthroline revealed a shift of AT2R and MasR bands upward with overlapping migration for their complexes which were sensitive...

Exploring high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for metabonomic analysis of apples.

Science.gov (United States)

Vermathen, Martina; Marzorati, Mattia; Vermathen, Peter

2012-01-01

Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of (1)H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue is presented probing its potential for metabonomic studies. The (1)H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.

MAS Based Distributed Automatic Generation Control for Cyber-Physical Microgrid System

Institute of Scientific and Technical Information of China (English)

Zhongwen Li; Chuanzhi Zang; Peng Zeng; Haibin Yu; Hepeng Li

2016-01-01

The microgrid is a typical cyber-physical microgrid system(CPMS). The physical unconventional distributed generators(DGs) are intermittent and inverter-interfaced which makes them very different to control. The cyber components,such as the embedded computer and communication network,are equipped with DGs, to process and transmit the necessary information for the controllers. In order to ensure system-wide observability, controllability and stabilization for the microgrid,the cyber and physical component need to be integrated. For the physical component of CPMS, the droop-control method is popular as it can be applied in both modes of operation to improve the grid transient performance. Traditional droop control methods have the drawback of the inherent trade-off between power sharing and voltage and frequency regulation. In this paper, the global information(such as the average voltage and the output active power of the microgrid and so on) are acquired distributedly based on multi-agent system(MAS). Based on the global information from cyber components of CPMS, automatic generation control(AGC) and automatic voltage control(AVC)are proposed to deal with the drawback of traditional droop control. Simulation studies in PSCAD demonstrate the effectiveness of the proposed control methods.

MAS Based Distributed Automatic Generation Control for Cyber-Physical Microgrid System

Institute of Scientific and Technical Information of China (English)

Zhongwen Li; Chuanzhi Zang; Peng Zeng; Haibin Yu; Hepeng Li

2016-01-01

The microgrid is a typical cyber-physical micro grid system (CPMS).The physical unconventional distributed generators (DGs) are intermittent and inverter-interfaced which makes them very different to control.The cyber components,such as the embedded computer and communication network,are equipped with DGs,to process and transmit the necessary information for the controllers.In order to ensure system-wide observability,controllability and stabilization for the microgrid,the cyber and physical component need to be integrated.For the physical component of CPMS,the droop-control method is popular as it can be applied in both modes of operation to improve the grid transient performance.Traditional droop control methods have the drawback of the inherent trade-off between power sharing and voltage and frequency regulation.In this paper,the global information (such as the average voltage and the output active power of the microgrid and so on) are acquired distributedly based on multi-agent system (MAS).Based on the global information from cyber components of CPMS,automatic generation control (AGC) and automatic voltage control (AVC) are proposed to deal with the drawback of traditional droop control.Simulation studies in PSCAD demonstrate the effectiveness of the proposed control methods.

Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

DEFF Research Database (Denmark)

Leonhardt, Julia; Villela, Daniel C.; Teichmann, Anke

2017-01-01

The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may in...

A numerical model for ocean ultra-low frequency noise: wave-generated acoustic-gravity and Rayleigh modes.

Science.gov (United States)

Ardhuin, Fabrice; Lavanant, Thibaut; Obrebski, Mathias; Marié, Louis; Royer, Jean-Yves; d'Eu, Jean-François; Howe, Bruce M; Lukas, Roger; Aucan, Jerome

2013-10-01

The generation of ultra-low frequency acoustic noise (0.1 to 1 Hz) by the nonlinear interaction of ocean surface gravity waves is well established. More controversial are the quantitative theories that attempt to predict the recorded noise levels and their variability. Here a single theoretical framework is used to predict the noise level associated with propagating pseudo-Rayleigh modes and evanescent acoustic-gravity modes. The latter are dominant only within 200 m from the sea surface, in shallow or deep water. At depths larger than 500 m, the comparison of a numerical noise model with hydrophone records from two open-ocean sites near Hawaii and the Kerguelen islands reveal: (a) Deep ocean acoustic noise at frequencies 0.1 to 1 Hz is consistent with the Rayleigh wave theory, in which the presence of the ocean bottom amplifies the noise by 10 to 20 dB; (b) in agreement with previous results, the local maxima in the noise spectrum support the theoretical prediction for the vertical structure of acoustic modes; and (c) noise level and variability are well predicted for frequencies up to 0.4 Hz. Above 0.6 Hz, the model results are less accurate, probably due to the poor estimation of the directional properties of wind-waves with frequencies higher than 0.3 Hz.

X-ray fluorescent analysis on Indo-Pacific glass beads from Sungai Mas archaeological sites, Kedah, Malaysia

International Nuclear Information System (INIS)

Zuliskandar Ramli; Nik Hassan Shuhaimi; Nik Abdul Rahman; Abdul Latif Samian

2011-01-01

Sungai Mas was an ancient port-kingdom located on West Coast of Peninsula Malaysia in a district of Kota Kuala Muda, Kedah, Malaysia. The port-kingdom evolved as an entrepot since fifth century AD and continuously visited by international trader from India, China, Middle East and Europe until eighteenth century AD. Sungai Mas was also one of the Indo-Pacific beads making centers in Southeast Asia since sixth to thirteenth century AD and also produced pottery and brick. X-ray fluorescent analysis (XRF) on Sungai Mas Indo-Pacific beads is carried out to determine whether the glass beads originated from Arikamedu, India or locally made by community in Sungai Mas. Totally, twenty-two samples of beads and beads materials assayed by XRF were chosen. Contents of nine major elements and nine trace elements, which might be present of flux, stabilizer, colorants or opacifier were examined. The elements Si, Na, K, Ca, Fe, Al, Ti, Mn, Mg, Cu, Pb, Zr, Sr, Ba, La, U, Ni and Cr were detectable in all samples. The concentration of elements found are discussed in terms of flux, silica or lead base glass, color and/or opacity of the glass beads and glass samples. The result showed that Sungai Mas produced their own Indo-Pacific beads from sixth to thirteenth century AD. (author)

Stanowisko badawcze do oceny efektów utwardzania mas ze szkłem wodnym

Directory of Open Access Journals (Sweden)

M. Stachowicz

2012-12-01

Full Text Available W pracy przedstawiono wyniki badań nad możliwością zastosowania nowego stanowiska badawczego do oceny, na podstawie końcowejzawartości wody, finalnego efektu utwardzania wybranymi metodami mas ze szkłem wodnym. Badania wykonano na innowacyjnym,mobilnym stanowisku mikrofalowej linii szczelinowej wykorzystującej zjawisko występowania fali stojącej w falowodzie. Badaniompoddano pięć mas sporządzonych z dostępnymi w handlu gatunkami szkła wodnego, które utwardzano trzema, wybranymi metodami:mikrofalową, klasyczną oraz w procesie CO2. Wykazano, na przykładzie mas ze szkłem wodnym, że prezentowane, mobilne stanowiskopomiarowe może, na podstawie określenia końcowej zawartości wody, służyć z powodzeniem do oceny ostatecznego efektu utwardzaniamas formierskich i rdzeniowych.

High-resolution numerical model of the middle and inner ear for a detailed analysis of radio frequency absorption

International Nuclear Information System (INIS)

Schmid, Gernot; Ueberbacher, Richard; Samaras, Theodoros; Jappel, Alexandra; Baumgartner, Wolf-Dieter; Tschabitscher, Manfred; Mazal, Peter R

2007-01-01

In order to enable a detailed analysis of radio frequency (RF) absorption in the human middle and inner ear organs, a numerical model of these organs was developed at a spatial resolution of 0.1 mm, based on a real human tissue sample. The dielectric properties of the liquids (perilymph and endolymph) inside the bony labyrinth were measured on samples of ten freshly deceased humans. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-3700 MHz were carried out. For typical output power values of real handheld mobile communication devices the obtained results showed only very small amounts of absorbed RF power in the middle and inner ear organs. Highest absorption in the middle and inner ear was found for the 400 MHz irradiation. In this case, the RF power absorbed inside the labyrinth and the vestibulocochlear nerve was as low as 166 μW and 12 μW, respectively, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power were found to be more than one order of magnitude lower than the values given above. These results indicate that temperature-related biologically relevant effects on the middle and inner ear, induced by the RF emissions of typical handheld mobile communication devices, are unlikely

Marker-assisted-selection (MAS): A fast track to increase genetic ...

African Journals Online (AJOL)

Mapping and tagging of agriculturally important genes have been greatly facilitated by an array of molecular markers in crop plants. Marker-assisted selection (MAS) is gaining considerable importance as it would improve the efficiency of plant breeding through precise transfer of genomic regions of interest (foreground ...

Reducing radiation dose in liver enhanced CT scan by setting mAs according to plain scan noise

International Nuclear Information System (INIS)

Yang Shangwen; He Jian; Yang Xianfeng; Zhou Kefeng; Xin Xiaoyan; Hu Anning; Zhu Bin

2013-01-01

Objective: To investigate the feasibility of setting mAs in liver enhanced CT scan according to plain scan noise with fixed mA CT scanner, in order to reduce the radiation dose. Methods: One hundred continuous patients underwent liver enhanced CT scan (group A) prospectively. Two hundred and fifty mAs was used in plain and enhanced CT scans. Noises of plain and venous phase CT images were measured, and the image quality was evaluated. The equation between mAs of enhanced scan and noise of plain scan image was derived. Another 100 continuous patients underwent liver enhanced CT scan (group B). Enhanced scan mAs was calculated from noise on plain scan by using the equation above. Noises on venous phase images were measured and the image quality was measured. Based on body mass index (BMI), patients in groups A and B were divided into three subgroups respectively: BMI < 18.5 kg/m 2 , 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 and BMI ≥ 25.0 kg/m 2 . Image quality score was compared with nonparametric rank sum test, CT dose index (CTDI) and effective dose (ED) were measured and compared between each subgroup with 2 independent samples t or t' test. Results: The equation between enhanced scan mAs (mAsX) and plain scan noise (SDp) was as follows: mAsX = mAs1 × [(0.989 × SDp + 1.06) /SDx] 2 , mAs1 = 250 mAs, SDx = 13. In patients with BMI < 18.5 kg/m 2 , ED of group A [(6.86 ± 0.38) mSv, n = 12] was significantly higher than group B [(2.66 ± 0.46) mSv, n = 10)] (t = 18.52, P < 0.01). In patients with 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 , ED of group A [(7.08 ± 0.91) mSv, n = 66] was significantly higher than group B [(4.50 ± 1.41) mSv, n = 73] (t' = 10.57, P < 0.01). In patients with BMI ≥ 25.0 kg/m 2 , there was no significant difference between EDs of group A (7.54 ± 0.62 mSv, n = 22) and group B [(8.19 ± 3.16) mSv, n = 17] (t' = 0.89, P = 0.39). Image quality of 5 patients in group A and none in group B did not meet the diagnostic requirement

Angiotensin type 2 receptor (AT2R) and receptor Mas

DEFF Research Database (Denmark)

Villela, Daniel; Leonhardt, Julia; Patel, Neal

2015-01-01

The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striki...

48 CFR 538.270 - Evaluation of multiple award schedule (MAS) offers.

Science.gov (United States)

2010-10-01

... SERVICES ADMINISTRATION SPECIAL CATEGORIES OF CONTRACTING FEDERAL SUPPLY SCHEDULE CONTRACTING Establishing and Administering Federal Supply Schedules 538.270 Evaluation of multiple award schedule (MAS) offers... determining the Government's price negotiation objectives, consider the following factors: (1) Aggregate...

Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones

International Nuclear Information System (INIS)

Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

2013-01-01

The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., −16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system. (paper)

Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones

Science.gov (United States)

Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

2013-12-01

The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., -16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system.

Stilistiskie izteiksmes līdzekļi Coca-Cola reklāmas plakātos

OpenAIRE

Gudre, Anete

2017-01-01

Šajā darbā tika pētīti mākslinieciskie un fonētiskie stila izteiksmes līdzekļi un to lietojums Coca-Cola reklāmas plakātos. Kā arī tika analizēti Coca-Cola reklāmas plakātu vizuālie elementi. Tēma tika izvēlēta, lai redzētu atšķirību starp mākslinieciskās izteiksmes līdzekļiem un, lai redzētu, cik bieži tie tiek izmantoti izvēlētajos reklāmas plakātos. Darbā tika aplūkoti vispopulārākie mākslinieciskās izteiksmes līdzekļi – metafora, epitets, personifikācija un hiperbola. Multimediju analīze ...

New marine commons along the Chilean coast – the management areas (MAs of Peñuelas and Chigualoco

Directory of Open Access Journals (Sweden)

Gloria L. Gallardo Fernández

2011-09-01

Full Text Available To halt degradation of benthic resources in Chile, management areas (MAs were set up under the Territorial Use Rights in Fisheries (TURFs framework in the late 1990s. Integrated into the global market, MAs have since expanded along the Chilean coast, involving thousands of small-scale artisanal fishers. This paper analyses how economic criteria relates to social and ecological performance of Chilean MAs, by applying TURFs, commons and co-management theory to two cases: MAs Peñuelas and Chigualoco. To collect and analyse data Participatory Rural Appraisal tools, interviews and official statistics and reports were used. Our results show that MAs’ economic benefits are connected to fluctuations on the global market. Adapting to changing world market prices then becomes paramount. TURFs’ main goal is ecological conservation, but achieving this seems to depend on meeting fishers’ livelihoods; failure to do so likely results in failure to meet conservation objectives. A serious weakness of the Chilean TURFs system is that it does not pay enough attention to fishers’ livelihoods or to the global market context. Furthermore, there is a strong relationship between good economic benefits and social sustainability. But irrespective of economic performance, fisher organizations have been empowered and gained increased resource control with the TURFs system. At policy level, a differentiated and more flexible system could be more suitable for existing heterogeneous MAs and their particular economic, social and ecological challenges. For improved economic sustainability and resource conservation, a system with multiple-species managing MAs could be promoted as well. Finally, to enhance theory of commons, co-management and TURFs, we argue for greater acknowledgement of TURFs’ social benefits in addition to economic assessments. More attention should also be paid to global market conditions of which MAs are dependent and in which they are embedded

The effect of FF-MAS on porcine cumulus-oocyte complex maturation, fertilization and pronucleus formation in vitro

DEFF Research Database (Denmark)

Færge, Inger; Strejcek, Frantisek; Laurincik, Jozef

2006-01-01

mechanically using a fine glass pipette under constant pH and in vitro fertilized with fresh semen (5 x 105 spermatozoa/ml). The presumptive zygotes were evaluated 18 h after fertilization. The addition of pFF increased the monospermic as well as the polyspermic penetration of oocytes. In the absence of p......FF, the addition of FF-MAS decreased the polyspermic penetration rate, wehreas FF-MAS in combination with pFF decreased monospermic and increased polyspermic penetration. The degeneration rate of ova decreased in the presence of FF-MAS irrespective of the presence or absence of pFF. In the absence of pFF, FF...

Study on MAs transmutation of accelerator-driven system sodium-cooled fast reactor loaded with metallic fuel

International Nuclear Information System (INIS)

Han Song; Yang Yongwei

2007-01-01

Through the analysis of the effect of heavy metal actinides on the effective multiplication constant (k eff ) of the core in accelerator-driven system (ADS) sodium-cooled fast reactor loaded with metallic fuel, we gave the method for determining fuel components. the characteristics of minor actinides (MAs) transmutation was analyzed in detail. 3D burn-up code COUPLE, which couples MCNP4c3 and ORIGEN2, was applied to the neutron simulation and burn up calculation. The results of optimized scheme shows that adjusting the proportion of 239 Pu and maintaining the value during the burn-up cycle is an efficient method of designing k eff and keeping stable during the burn-up cycle. Spallation neutrons lead to the neutron spectrum harder at inner core than that at outer core. It is in favor of improving MA's fission cross sections and the capture-to-fission ratio. The total MAs transmutation support ratio 8.3 achieves excellent transmutation effect. For higher flux at inner core leads to obvious differences on transmutation efficiency,only disposing MAs at inner core is in favor of decreasing the loading mass and improving MAs transmutation effect. (authors)

Role of Mas receptor in renal blood flow response to angiotensin-(1-7) in ovariectomized estradiol treated rats.

Science.gov (United States)

Saberi, Shadan; Dehghani, Aghdas; Nematbakhsh, Mehdi

2016-01-01

The angiotensin 1-7 (Ang 1-7), is abundantly produced in kidneys and antagonizes the function of angiotensin II through Mas receptor (MasR) or other unknown mechanisms. In the current study, the role of MasR and steroid hormone estrogen on renal blood flow response to Ang 1-7 administration was investigated in ovariectomized (OV) female rats. OV female Wistar-rats received estradiol (500 μg/kg/week) or vehicle for two weeks. In the day of the experiment, the animals were anesthetized, cannulated, and the responses including mean arterial pressure, renal blood flow (RBF), and renal vascular resistance at the constant level of renal perfusion pressure to graded infusion of Ang 1-7 at 0, 100 and 300 ng/kg/min were determined in OV and OV estradiol-treated (OVE) rats, treated with vehicle or MasR antagonist; A779. RBF response to Ang 1-7 infusion increased dose-dependently in vehicle (Pdose <0.001) and A779-treated (Pdose <0.01) animals. However, when MasR was blocked, the RBF response to Ang 1-7 significantly increased in OV animals compared with OVE rats (P<0.05). When estradiol was limited by ovariectomy, A779 increased RBF response to Ang 1-7 administration, while this response was attenuated in OVE animals.

The demands and benefits of ergonomics in Sri Lankan apparel industry: A case study at MAS holdings.

Science.gov (United States)

Abeysekera, John; Illankoon, Prasanna

2016-10-17

Apparel exports bring in sizeable foreign income to Sri Lanka. To protect and promote this industry is a paramount need. This can be carried out by applying Human Factors/Ergonomics (HFE) which has proved to control negative effects at work places. This paper reports a case study which describes the demands and benefits of HFE in MAS Holdings which owns a large share of the apparel industry in Sri Lanka. The study consisted of walk through observation survey, a questionnaire survey and ergonomic work place analysis followed by a training programme to selected employees in three companies. Positive responses to questionnaires revealed good ergonomic practices in the work places surveyed. Ergonomically unfit chairs and potential hazards e.g. exposure to noise and hot environment were detected. It is seen that MAS have introduced strategies originated by Toyota Production System viz. 5S, Kaizen, six sigma etc., which are in fact ergonomic methods. A progressive project MAS boast of viz. 'MAS Operating System' (MOS) empowers training and development to employees. MAS Holdings has adequately realized the benefits of applying HFE as evident by the number of awards received. Relevant companies were advised to take appropriate corrective measures to control the potential hazards.

Minho Affective Sentences (MAS): Probing the roles of sex, mood, and empathy in affective ratings of verbal stimuli.

Science.gov (United States)

Pinheiro, Ana P; Dias, Marcelo; Pedrosa, João; Soares, Ana P

2017-04-01

During social communication, words and sentences play a critical role in the expression of emotional meaning. The Minho Affective Sentences (MAS) were developed to respond to the lack of a standardized sentence battery with normative affective ratings: 192 neutral, positive, and negative declarative sentences were strictly controlled for psycholinguistic variables such as numbers of words and letters and per-million word frequency. The sentences were designed to represent examples of each of the five basic emotions (anger, sadness, disgust, fear, and happiness) and of neutral situations. These sentences were presented to 536 participants who rated the stimuli using both dimensional and categorical measures of emotions. Sex differences were also explored. Additionally, we probed how personality, empathy, and mood from a subset of 40 participants modulated the affective ratings. Our results confirmed that the MAS affective norms are valid measures to guide the selection of stimuli for experimental studies of emotion. The combination of dimensional and categorical ratings provided a more fine-grained characterization of the affective properties of the sentences. Moreover, the affective ratings of positive and negative sentences were not only modulated by participants' sex, but also by individual differences in empathy and mood state. Together, our results indicate that, in their quest to reveal the neurofunctional underpinnings of verbal emotional processing, researchers should consider not only the role of sex, but also of interindividual differences in empathy and mood states, in responses to the emotional meaning of sentences.

29Si MAS NMR for the zeolite Y - gallium oxide system

International Nuclear Information System (INIS)

Sulikowski, B.; Derewinski, M.; Olejniczak, Z.; Segnowski, S.

1994-01-01

Wide-pore zeolites modified by gallium oxide has been prepared for catalytic use. Its physico-chemical and catalytic properties have been studied. The structure changes of the catalyst have been investigated by means of MAS NMR spectroscopy. Spectra of 29 Si has been described and discussed

HR-MAS NMR allied to chemometric on Hancornia speciosa varieties differentiation

Energy Technology Data Exchange (ETDEWEB)

Flores, Igor S. [Instituto Federal de Goiás (IFG), Luziânia, GO (Brazil); Silva, Andressa K.; Chaves, Lazaro J.; Collevatti, Rosane G.; Lião, Luciano M., E-mail: lucianoliao@ufg.br [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil); Furquim, Leonnardo C. [Faculdade Objetivo, GO (Brazil); Castro, Carlos F.S. [Instituto Federal de Educação, Ciência e Tecnologia Goiano (IFGoiano), GO (Brazil)

2018-05-01

This work describes the potential of chemometric analyses applied to {sup 1}H high-resolution magic angle spinning nuclear magnetic resonance ({sup 1}H HR-MAS NMR) data for the chemotaxonomic investigation of Hancornia speciosa (Apocynaceae) varieties. This plant, popularly known as mangaba, has a complex morphological differentiation and thus chemical analyses can be used for their taxonomic classification. In comparison to traditional techniques, {sup 1}H HR-MAS NMR allied with chemometrics provided a simple and low cost method for chemotaxonomy. Leaves of four varieties of H. speciosa from a common garden experiment was studied and demonstrated that H. speciosa var. speciosa differs from others due to its specific metabolic profile, and var. pubescens was discriminated based on its high phenolic compound content. The distinction between the latter variety and gardineri is important once it allows for the selection of samples with greater commercial value, once they produce the largest and heaviest fruits. (author)

NOMEX - a universal diagnostic dosemeter, mA.s, and kV meter for acceotance test measurements and quality assurance

International Nuclear Information System (INIS)

Hein, G.; Pychlau, P.; Schuele, E.

1992-01-01

A universal diagnostic dosemeter is introduced which was designed for acceptance test measurements and quality assurance. It can also be used for periodic constancy checks. To facilitate the comprehensive tests, the NOMEX can measure all important quantities, such as dose and dose rate, mean peak voltage, exposure time, mA.s product, dose per mA.s, dose per pulse, attenuation factor, relative standard deviation and length dose product in CT. All these quantities, except the mA.s product, are measured non-invasively. The instrument's concept, its applications and technical data are described. (author)

Optimizing switching frequency of the soliton transistor by numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Izadyar, S., E-mail: S_izadyar@yahoo.co [Department of Electronics, Khaje Nasir Toosi University of Technology, Shariati Ave., Tehran (Iran, Islamic Republic of); Niazzadeh, M.; Raissi, F. [Department of Electronics, Khaje Nasir Toosi University of Technology, Shariati Ave., Tehran (Iran, Islamic Republic of)

2009-10-15

In this paper, by numerical simulations we have examined different ways to increase the soliton transistor's switching frequency. Speed of the solitons in a soliton transistor depends on various parameters such as the loss of the junction, the applied bias current, and the transmission line characteristics. Three different ways have been examined; (i) decreasing the size of the transistor without losing transistor effect. (ii) Decreasing the amount of loss of the junction to increase the soliton speed. (iii) Optimizing the bias current to obtain maximum possible speed. We have obtained the shortest possible length to have at least one working soliton inside the transistor. The dimension of the soliton can be decreased by changing the inductance of the transmission line, causing a further decrease in the size of the transistor, however, a trade off between the size and the inductance is needed to obtain the optimum switching speed. Decreasing the amount of loss can be accomplished by increasing the characteristic tunneling resistance of the device, however, a trade off is again needed to make soliton and antisoliton annihilation possible. By increasing the bias current, the forces acting the solitons increases and so does their speed. Due to nonuniform application of bias current a self induced magnetic field is created which can result in creation of unwanted solitons. Optimum bias current application can result in larger bias currents and larger soliton speed. Simulations have provided us with such an arrangement of bias current paths.

Optimizing switching frequency of the soliton transistor by numerical simulation

International Nuclear Information System (INIS)

Izadyar, S.; Niazzadeh, M.; Raissi, F.

2009-01-01

In this paper, by numerical simulations we have examined different ways to increase the soliton transistor's switching frequency. Speed of the solitons in a soliton transistor depends on various parameters such as the loss of the junction, the applied bias current, and the transmission line characteristics. Three different ways have been examined; (i) decreasing the size of the transistor without losing transistor effect. (ii) Decreasing the amount of loss of the junction to increase the soliton speed. (iii) Optimizing the bias current to obtain maximum possible speed. We have obtained the shortest possible length to have at least one working soliton inside the transistor. The dimension of the soliton can be decreased by changing the inductance of the transmission line, causing a further decrease in the size of the transistor, however, a trade off between the size and the inductance is needed to obtain the optimum switching speed. Decreasing the amount of loss can be accomplished by increasing the characteristic tunneling resistance of the device, however, a trade off is again needed to make soliton and antisoliton annihilation possible. By increasing the bias current, the forces acting the solitons increases and so does their speed. Due to nonuniform application of bias current a self induced magnetic field is created which can result in creation of unwanted solitons. Optimum bias current application can result in larger bias currents and larger soliton speed. Simulations have provided us with such an arrangement of bias current paths.

Lielveikalu RIMI reklāmas kampaņas ─ auditorijas uzmanības piesaistes analīze

OpenAIRE

Fjodorova, Margarita

2008-01-01

Mana darba tēma ir „Lielveikalu „RIMI” reklāmas kampaņas – auditorijas uzmanības piesaistes analīze.” Es apskatu 2003. – 2008.gada „RIMI” video reklāmas, lai pierādītu sava darba hipotēzi, ka „RIMI” lielveikalu video reklāmās laika posmā no 2003. līdz 2008. gadam nav bijis vienotu auditorijas uzmanības piesaistes elementu, bet tie tika ieturēti tikai kādas konkrētas reklāmas kampaņas robežās kā galvenie auditorijas uzmanības piesaistes elementi. Sava darba teorētiskajā daļā es pieturēšos pie ...

Participation and Performance Reporting for the Alternate Assessment Based on Modified Achievement Standards (AA-MAS). Technical Report 58

Science.gov (United States)

Albus, Deb; Thurlow, Martha L.; Lazarus, Sheryl S.

2011-01-01

This report examines publicly reported participation and performance data for the alternate assessment based on modified achievement standards (AA-MAS). The authors' analysis of these data included all states publicly reporting AA-MAS data, regardless of whether they had received approval to use the results for Title I accountability calculations.…

Numerical studies on the stabilization of neoclassical tearing modes by radio frequency current drive

International Nuclear Information System (INIS)

Yu, Q.; Zhang, X.D.; Guenter, S.

2004-01-01

Numerical modeling on the stabilization of neoclassical tearing modes by localized radio frequency (rf) current drive has been carried out to study the effects of various wave and plasma parameters on the stabilization and the associated physics. The change of the rf current profile due to the magnetic island has been taken into account by modeling the two-dimensional transport of the fast electrons induced by the rf wave. It is found that, when the rf deposition width is much larger than the island width, the modulated rf current drive to deposit the rf current around the island's o point has a stronger stabilizing effect than a nonmodulated one. The slowing down time of the fast electrons and the initial island width when applying the rf wave are also found to be important in determining the stabilizing effect

Mas-allatotropin in the developing antennal lobe of the sphinx moth Manduca sexta: distribution, time course, developmental regulation, and colocalization with other neuropeptides.

Science.gov (United States)

Utz, Sandra; Huetteroth, Wolf; Vömel, Matthias; Schachtner, Joachim

2008-01-01

The paired antennal lobes (ALs) of the sphinx moth Manduca sexta serve as a well-established model for studying development of the primary integration centers for odor information in the brain. To further reveal the role of neuropeptides during AL development, we have analyzed cellular distribution, developmental time course, and regulation of the neuropeptide M. sexta allatotropin (Mas-AT). On the basis of morphology and appearance during AL formation, seven major types of Mas-AT-immunoreactive (ir) cells could be distinguished. Mas-AT-ir cells are identified as local, projection, and centrifugal neurons, which are either persisting larval or newly added adult-specific neurons. Complementary immunostaining with antisera against two other neuropeptide families (A-type allatostatins, RFamides) revealed colocalization within three of the Mas-AT-ir cell types. On the basis of this neurochemistry, the most prominent type of Mas-AT-ir neurons, the local AT neurons (LATn), could be divided in three subpopulations. The appearance of the Mas-AT-ir cell types occurring during metamorphosis parallels the rising titer of the developmental hormone 20-hydroxyecdysone (20E). Artificially shifting the 20E titer to an earlier developmental time point resulted in the precocious occurrence of Mas-AT immunostaining. This result supports the hypothesis that the pupal rise of 20E is causative for Mas-AT expression during AL development. Comparing localization and developmental time course of Mas-AT and other neuropeptides with the time course of AL formation suggests various functions for these neuropeptides during development, including an involvement in the formation of the olfactory glomeruli.

Numerical solution of optimal departure frequency of Taipei TMS

Science.gov (United States)

Young, Lih-jier; Chiu, Chin-Hsin

2016-05-01

Route Number 5 (Bannan Line) of Taipei Mass Rapid Transit (MRT) is the most popular line in the Taipei Metro System especially during rush hours periods. It has been estimated there are more than 8,000 passengers on the ticket platform during 18:00∼19:00 at Taipei main station. The purpose of this research is to predict a specific departure frequency of passengers per train. Monte Carlo Simulation will be used to optimize departure frequency according to the passenger information provided by 22 stations, i.e., 22 random variables of route number 5. It is worth mentioning that we used 30,000 iterations to get the different samples of the optimization departure frequency, i.e., 10 trains/hr which matches the practical situation.

Numerical study of the generation and propagation of ultralow-frequency waves by artificial ionospheric F region modulation at different latitudes

Directory of Open Access Journals (Sweden)

X. Xu

2016-09-01

Full Text Available Powerful high-frequency (HF radio waves can be used to efficiently modify the upper-ionospheric plasmas of the F region. The pressure gradient induced by modulated electron heating at ultralow-frequency (ULF drives a local oscillating diamagnetic ring current source perpendicular to the ambient magnetic field, which can act as an antenna radiating ULF waves. In this paper, utilizing the HF heating model and the model of ULF wave generation and propagation, we investigate the effects of both the background ionospheric profiles at different latitudes in the daytime and nighttime ionosphere and the modulation frequency on the process of the HF modulated heating and the subsequent generation and propagation of artificial ULF waves. Firstly, based on a relation among the radiation efficiency of the ring current source, the size of the spatial distribution of the modulated electron temperature and the wavelength of ULF waves, we discuss the possibility of the effects of the background ionospheric parameters and the modulation frequency. Then the numerical simulations with both models are performed to demonstrate the prediction. Six different background parameters are used in the simulation, and they are from the International Reference Ionosphere (IRI-2012 model and the neutral atmosphere model (NRLMSISE-00, including the High Frequency Active Auroral Research Program (HAARP; 62.39° N, 145.15° W, Wuhan (30.52° N, 114.32° E and Jicamarca (11.95° S, 76.87° W at 02:00 and 14:00 LT. A modulation frequency sweep is also used in the simulation. Finally, by analyzing the numerical results, we come to the following conclusions: in the nighttime ionosphere, the size of the spatial distribution of the modulated electron temperature and the ground magnitude of the magnetic field of ULF wave are larger, while the propagation loss due to Joule heating is smaller compared to the daytime ionosphere; the amplitude of the electron temperature

Modified Ashworth Scale (MAS) Model based on Clinical Data Measurement towards Quantitative Evaluation of Upper Limb Spasticity

Science.gov (United States)

Puzi, A. Ahmad; Sidek, S. N.; Mat Rosly, H.; Daud, N.; Yusof, H. Md

2017-11-01

Spasticity is common symptom presented amongst people with sensorimotor disabilities. Imbalanced signals from the central nervous systems (CNS) which are composed of the brain and spinal cord to the muscles ultimately leading to the injury and death of motor neurons. In clinical practice, the therapist assesses muscle spasticity using a standard assessment tool like Modified Ashworth Scale (MAS), Modified Tardiue Scale (MTS) or Fugl-Meyer Assessment (FMA). This is done subjectively based on the experience and perception of the therapist subjected to the patient fatigue level and body posture. However, the inconsistency in the assessment is prevalent and could affect the efficacy of the rehabilitation process. Thus, the aim of this paper is to describe the methodology of data collection and the quantitative model of MAS developed to satisfy its description. Two subjects with MAS of 2 and 3 spasticity levels were involved in the clinical data measurement. Their level of spasticity was verified by expert therapist using current practice. Data collection was established using mechanical system equipped with data acquisition system and LABVIEW software. The procedure engaged repeated series of flexion of the affected arm that was moved against the platform using a lever mechanism and performed by the therapist. The data was then analyzed to investigate the characteristics of spasticity signal in correspondence to the MAS description. Experimental results revealed that the methodology used to quantify spasticity satisfied the MAS tool requirement according to the description. Therefore, the result is crucial and useful towards the development of formal spasticity quantification model.

1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

International Nuclear Information System (INIS)

Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M.; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P.; Alcantara, Glaucia B.

2014-01-01

High resolution magic angle spinning 1 H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

Improvement of Frequency Locking Algorithm for Atomic Frequency Standards

Science.gov (United States)

Park, Young-Ho; Kang, Hoonsoo; Heyong Lee, Soo; Eon Park, Sang; Lee, Jong Koo; Lee, Ho Seong; Kwon, Taeg Yong

2010-09-01

The authors describe a novel method of frequency locking algorithm for atomic frequency standards. The new algorithm for locking the microwave frequency to the Ramsey resonance is compared with the old one that had been employed in the cesium atomic beam frequency standards such as NIST-7 and KRISS-1. Numerical simulations for testing the performance of the algorithm show that the new method has a noise filtering performance superior to the old one by a factor of 1.2 for the flicker signal noise and 1.4 for random-walk signal noise. The new algorithm can readily be used to enhance the frequency stability for a digital servo employing the slow square wave frequency modulation.

Theory for cross effect dynamic nuclear polarization under magic-angle spinning in solid state nuclear magnetic resonance: the importance of level crossings.

Science.gov (United States)

Thurber, Kent R; Tycko, Robert

2012-08-28

We present theoretical calculations of dynamic nuclear polarization (DNP) due to the cross effect in nuclear magnetic resonance under magic-angle spinning (MAS). Using a three-spin model (two electrons and one nucleus), cross effect DNP with MAS for electron spins with a large g-anisotropy can be seen as a series of spin transitions at avoided crossings of the energy levels, with varying degrees of adiabaticity. If the electron spin-lattice relaxation time T(1e) is large relative to the MAS rotation period, the cross effect can happen as two separate events: (i) partial saturation of one electron spin by the applied microwaves as one electron spin resonance (ESR) frequency crosses the microwave frequency and (ii) flip of all three spins, when the difference of the two ESR frequencies crosses the nuclear frequency, which transfers polarization to the nuclear spin if the two electron spins have different polarizations. In addition, adiabatic level crossings at which the two ESR frequencies become equal serve to maintain non-uniform saturation across the ESR line. We present analytical results based on the Landau-Zener theory of adiabatic transitions, as well as numerical quantum mechanical calculations for the evolution of the time-dependent three-spin system. These calculations provide insight into the dependence of cross effect DNP on various experimental parameters, including MAS frequency, microwave field strength, spin relaxation rates, hyperfine and electron-electron dipole coupling strengths, and the nature of the biradical dopants.

Banku reklāmas stratēģiju un valsts ekonomiskā stāvokļa mijiedarbība

OpenAIRE

Vernere, Elīna

2009-01-01

Darba tēma ir banku reklāmas stratēģiju un valsts ekonomiskā stāvokļa mijiedarbība. Galvenais pētījuma mērķis bija izprast, kā pašreizējā valsts ekonomiskā situācija izmainījusi sabiedrības vajadzības, pieprasījumu pēc banku pakalpojumiem un līdz ar to arī banku komunikāciju ar saviem klientiem ar vides reklāmas ziņojumu palīdzību. Galvenais pētījuma uzsvars tika likts uz reklāmas ziņojumu emocionālajiem un racionālajiem aspektiem. Papildus veiktajam pētījumam tika apskatīta arī reklāmas teor...

Le Kāmasūtra et la « pulsion shastrique » en Inde

OpenAIRE

Naudou, Elizabeth

2013-01-01

Le mot « shastrique » fait référence au traité (śāstra) d’où sont issus les Kāmasūtra, (plus généralement appelé le Kāmasūtra), « aphorismes sur l’amour » : le Kāmaśāstra, « traité sur l’amour ». Qui dit śāstra, dit, en Inde, exposé religieux ou scientifique, d’où l’expression « pulsion shastrique » que l’on pourrait rendre par « pulsion encyclopédique énumérative et classificatoire ». Le but de cet exposé est de replacer le texte dans cette structure mentale typiquement indienne, qui reflète...

EVALUASI DAYA TAHAN IKAN MAS HASIL SELEKSI BERDASARKAN MARKA MOLEKULER MHC-II TERHADAP INFEKSI KOI HERPES VIRUS

Directory of Open Access Journals (Sweden)

Erma Primanita Hayuningtyas

2015-03-01

mengevaluasi daya tahan benih ikan mas F-1 terseleksi terhadap infeksi KHV melalui uji tantang. Sebagai pembanding, digunakan ikan mas populasi benih F-1 non-seleksi dan populasi benih ikan mas dari unit pembenihan rakyat (UPR. Ikan uji berupa benih ikan mas Rajadanu berumur dua bulan dengan bobot ratarata 5,5±0,5 g. Jumlah benih pada masing-masing wadah perlakuan sebanyak 30 ekor dengan tiga kali pengulangan. Wadah pengujian berupa akuarium berukuran 40 cm x 60 cm x 40 cm dengan kepadatan 1 ekor/L. Parameter yang diamati adalah sintasan, deteksi KHV, analisis ekspresi gen MHC-II, dan gambaran darah ikan. Hasil penelitian menunjukkan bahwa populasi benih F-1 terseleksi memiliki daya tahan lebih baik dengan sintasan 93,33% dibandingkan populasi benih F-1 non-seleksi sebesar 85,55% dan populasi benih dari UPR sebesar 81,11%. Daya tahan yang tinggi pada populasi benih F-1 terseleksi didukung oleh hasil deteksi KHV yang negatif dan ersentase jumlah limfosit yang lebih tinggi sebesar 91,67%; serta rendahnya persentase monosit dan heterofil, selain itu, tidak adanya eosinofil dan basofil. Ekspresi gen MHC-II terdeteksi pada berbagai organ, ekspresi tertinggi ditemukan pada organ limpa.

In situ high temperature MAS NMR study of the mechanisms of catalysis. Ethane aromatization on Zn-modified zeolite BEA.

Science.gov (United States)

Arzumanov, Sergei S; Gabrienko, Anton A; Freude, Dieter; Stepanov, Alexander G

2009-04-01

Ethane conversion into aromatic hydrocarbons over Zn-modified zeolite BEA has been analyzed by high-temperature MAS NMR spectroscopy. Information about intermediates (Zn-ethyl species) and reaction products (mainly toluene and methane), which were formed under the conditions of a batch reactor, was obtained by (13)C MAS NMR. Kinetics of the reaction, which was monitored by (1)H MAS NMR in situ at the temperature of 573K, provided information about the reaction mechanism. Simulation of the experimental kinetics within the frames of the possible kinetic schemes of the reaction demonstrates that a large amount of methane evolved under ethane aromatization arises from the stage of direct ethane hydrogenolysis.

Chemical profile of beans cultivars (Phaseolus vulgaris) by 1H NMR - high resolution magic angle spinning (HR-MAS);Perfil quimico de cultivares de feijao (Phaseolus vulgaris) pela tecnica de high resolution magic angle spinning (HR-MAS)

Energy Technology Data Exchange (ETDEWEB)

Liao, Luciano Morais; Choze, Rafael; Cavalcante, Pedro Paulo Araujo; Santos, Suzana da Costa; Ferri, Pedro Henrique, E-mail: luciano@quimica.ufg.b [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Quimica; Ferreira, Antonio Gilberto [Universidade Federal de Sao Carlos (UFScar), SP (Brazil). Dept. de Quimica

2010-07-01

The application of one-dimensional proton high-resolution magic angle spinning ({sup 1}H HR-MAS) NMR combined with a typical advantages of solid and liquid-state NMR techniques was used as input variables for the multivariate statistical analysis. In this paper, different cultivars of beans (Phaseolus vulgaris) developed and in development by EMBRAPA - Arroz e Feijao were analyzed by {sup 1}H HR-MAS, which have been demonstrated to be a valuable tool in its differentiation according chemical composition and avoid the manipulation of the samples as used in other techniques. (author)

Evaluation of high frequency ghost cavitation emissions for two different seismic air-gun arrays using numerical modelling

Science.gov (United States)

Khodabandeloo, Babak; Landrø, Martin

2017-04-01

Sound is deployed by marine mammals for variety of vital purposes such as finding food, communication, echolocation, etc. On the other hand human activities generate underwater noise. One major type of acoustic source is marine seismic acquisition which is carried out to image layers beneath the seabed exploiting reflected acoustic and elastic waves. Air-gun arrays are the most common and efficient marine seismic sources. Field measurements using broad band hydrophones have revealed that acoustic energies emitted by air-gun arrays contains frequencies from a few Hz up to tens of kHz. Frequencies below 200 Hz benefit seismic imaging and the rest is normally considered as wasted energy. On the other hand, the high frequency range (above 200 Hz) overlaps with hearing curves of many marine mammals and especially toothed whales and may have an impact on their behavior. A phenomenon called ghost cavitation is recently recognized to be responsible for a major part of these high frequencies (> 5 kHz). Acoustic pressure waves of individual air guns reflected from sea surface can cause the hydrostatic pressure to drop towards zero close to the source array. In these regions there is a high probability for water vapor cavity growth and subsequent collapse. We have simulated ghost cavitation cloud using numerical modelling and the results are validated by comparing with field measurements. The model is used to compare the amount of high frequency noise due to ghost cavitation for two different air gun arrays. Both of the arrays have three subarrays but the array distance for the one with 2730 in3 air volume is 6 meters and for the slightly bigger array (3250 in3 in air volume) the subarrays are separated by 8 meters. Simulation results indicate that the second array, despite larger subarray distance, generates stronger ghost cavitation signal.

A direct numerical simulation investigation of the synthetic jet frequency effects on separation control of low-Re flow past an airfoil

KAUST Repository

Zhang, Wei

2015-05-05

We present results of direct numerical simulations of a synthetic jet (SJ) based separation control of flow past a NACA-0018 (National Advisory Committee for Aeronautics) airfoil, at 10° angle of attack and Reynolds number 104 based on the airfoil chord length C and uniform inflow velocity U 0. The actuator of the SJ is modeled as a spanwise slot on the airfoil leeward surface and is placed just upstream of the leading edge separation position of the uncontrolled flow. The momentum coefficient of the SJ is chosen at a small value 2.13 × 10−4 normalized by that of the inflow. Three forcing frequencies are chosen for the present investigation: the low frequency (LF) F + = feC/U 0 = 0.5, the medium frequency (MF) F + = 1.0, and the high frequency (HF) F + = 4.0. We quantify the effects of forcing frequency for each case on the separation control and related vortex dynamics patterns. The simulations are performed using an energy conservative fourth-order parallel code. Numerical results reveal that the geometric variation introduced by the actuator has negligible effects on the mean flow field and the leading edge separation pattern; thus, the separation control effects are attributed to the SJ. The aerodynamic performances of the airfoil, characterized by lift and lift-to-drag ratio, are improved for all controlled cases, with the F + = 1.0 case being the optimal one. The flow in the shear layer close to the actuator is locked to the jet, while in the wake this lock-in is maintained for the MF case but suppressed by the increasing turbulent fluctuations in the LF and HF cases. The vortex evolution downstream of the actuator presents two modes depending on the frequency: the vortex fragmentation and merging mode in the LF case where the vortex formed due to the SJ breaks up into several vortices and the latter merge as convecting downstream; the discrete vortices mode in the HF case where discrete vortices form and convect downstream without any fragmentation and

A direct numerical simulation investigation of the synthetic jet frequency effects on separation control of low-Re flow past an airfoil

KAUST Repository

Zhang, Wei; Samtaney, Ravi

2015-01-01

We present results of direct numerical simulations of a synthetic jet (SJ) based separation control of flow past a NACA-0018 (National Advisory Committee for Aeronautics) airfoil, at 10° angle of attack and Reynolds number 104 based on the airfoil chord length C and uniform inflow velocity U 0. The actuator of the SJ is modeled as a spanwise slot on the airfoil leeward surface and is placed just upstream of the leading edge separation position of the uncontrolled flow. The momentum coefficient of the SJ is chosen at a small value 2.13 × 10−4 normalized by that of the inflow. Three forcing frequencies are chosen for the present investigation: the low frequency (LF) F + = feC/U 0 = 0.5, the medium frequency (MF) F + = 1.0, and the high frequency (HF) F + = 4.0. We quantify the effects of forcing frequency for each case on the separation control and related vortex dynamics patterns. The simulations are performed using an energy conservative fourth-order parallel code. Numerical results reveal that the geometric variation introduced by the actuator has negligible effects on the mean flow field and the leading edge separation pattern; thus, the separation control effects are attributed to the SJ. The aerodynamic performances of the airfoil, characterized by lift and lift-to-drag ratio, are improved for all controlled cases, with the F + = 1.0 case being the optimal one. The flow in the shear layer close to the actuator is locked to the jet, while in the wake this lock-in is maintained for the MF case but suppressed by the increasing turbulent fluctuations in the LF and HF cases. The vortex evolution downstream of the actuator presents two modes depending on the frequency: the vortex fragmentation and merging mode in the LF case where the vortex formed due to the SJ breaks up into several vortices and the latter merge as convecting downstream; the discrete vortices mode in the HF case where discrete vortices form and convect downstream without any fragmentation and

El medievalismo fértil de Paloma Díaz-Mas

Directory of Open Access Journals (Sweden)

Rafael M. Mérida Jiménez

2001-01-01

Full Text Available The author of this article is concerned with trying to understand why Paloma Díaz-Mas, the writer of such an excellent novel as La tierra fértil (1999, has not received much critical attention. He underlines three main reasons. First, she does not live in Madrid or Barcelona and so she is far away from the main centres of cultural power. Second, she teaches Spanish literature in the Basque Country, a political and linguistic community which significantly differs from that of many other writers. Third, she writes historical novels, which does not appear to be very fashionable in Spain these days. Moreover, Díaz-Mas is a woman writer who does not make use of the most commonly available feminine patterns, and she does not seem to offer a model easy to include in a given feminist methodology either. However, Mérida-Jiménez argues that Paloma provides an intelligent deconstruction of “male authority” through subtle rhetorical means, as well as a representation of the weakness of his “domination” in very innovative ways, such as those derived from the dialectics between history and fiction, centrality and marginality, heterosexuality and homosexuality, individual and society, dream and reason or tradition and modernity.

{sup 1}H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Química. Lab. de RMN; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Ciências Biológicas. Laboratório Genética Molecular e Citogenética; Alcantara, Glaucia B., E-mail: glaucia.alcantara@ufms.br [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Inst. de Química

2014-07-01

High resolution magic angle spinning {sup 1}H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

CONCEPTUALIZACIÓN Y ANÁLISIS DE UN SISTEMA MULTI-AGENTE PEDAGÓGICO UTILIZANDO LA METODOLOGÍA MAS-COMMONKADS

Directory of Open Access Journals (Sweden)

JOVANI ALBERTO JIMÉNEZ BUILES

2009-01-01

Full Text Available En este artículo se presentan la conceptualización y el análisis de un sistema multi-agente (MAS pedagógico utilizando la metodología MAS-CommonKADS; la cual es una de las más reconocidaspara el modelado de MAS. El propósito de la fase de conceptualización es comprender el problema, identificar los actores activos y pasivo, además de elaborar los requisitos que permitan formular unos objetivos para generar la solución. En la fase de análisis se definen los modelos de agente, tareas, coordinación, comunicación, organizacióny experiencia (conocimientos. Ambas fases fueron validadas mediante la construcción del ambiente multi agente pedagógico ALLEGRO.

Deuterium and lithium-6 MAS NMR studies of manganese oxide electrode materials

Science.gov (United States)

Paik, Younkee

Electrolytic manganese dioxide (EMD) is used world wide as the cathode materials in both lithium and alkaline primary (non-rechargeable) batteries. We have developed deuterium and lithium MAS NMR techniques to study EMD and related manganese oxides and hydroxides, where diffraction techniques are of limited value due to a highly defective nature of the structures. Deuterons in EMD, manganite, groutite, and deuterium-intercalated pyrolusite and ramsdellite were detected by NMR, for the first time, and their locations and motions in the structures were analyzed by applying variable temperature NMR techniques. Discharge mechanisms of EMD in alkaline (aqueous) electrolytes were studied, in conjunction with step potential electrochemical spectroscopic (SPECS) method, and five distinctive discharge processes were proposed. EMD is usually heat-treated at about 300--400°C to remove water to be used in lithium batteries. Details of the effects of heat-treatment, such as structural and compositional changes as a function of heat-treatment temperature, were studied by a combination of MAS NMR, XRD, and thermogravimetric analysis. Lithium local environments in heat-treated EMD (HEMD) that were discharged in lithium cells, were described in terms of related environments found in model compounds pyrolusite and ramsdellite where specific Li + sites were detected by MAS NMR and the hyperfine shift scale method of Grey et al. Acid-leaching of Li2MnO3 represents an approach for synthesizing new or modified manganese oxide electrode materials for lithium rechargeable batteries. Progressive removal of lithium from specific crystallographic sites, followed by a gradual change of the crystal structure, was monitored by a combination of NMR and XRD techniques.

El Proyecto Sismico "LARSE" - Trabajando Hacia un Futuro con Mas Seguridad para Los Angeles

Science.gov (United States)

Henyey, Thomas L.; Fuis, Gary S.; Benthien, Mark L.; Burdette, Thomas R.; Christofferson, Shari A.; Clayton, Robert W.; Criley, Edward E.; Davis, Paul M.; Hendley, James W.; Kohler, Monica D.; Lutter, William J.; McRaney, John K.; Murphy, Janice M.; Okaya, David A.; Ryberg, Trond; Simila, Gerald W.; Stauffer, Peter H.

1999-01-01

La region de Los Angeles contiene una red de fallas activas, incluyendo muchas fallas por empuje que son profundas y no rompen la superficie de la tierra. Estas fallas ocultas incluyen la falla anteriormente desconocida que fue responsable por la devastacion que ocurrio durante el terremoto de Northridge en enero de 1994, el terremoto mas costoso en la historia de los Estados Unidos. El Experimento Sismico en la Region de Los Angeles (Los Angeles Region Seismic Experiment, LARSE), esta localizando los peligros ocultos de los terremotos debajo de la region de Los Angeles para mejorar la construccion de las estructuras que pueden apoyar terremotos que son inevitables en el futuro, y que ayudaran a los cientificos determinar donde occurira el sacudimento mas fuerte y poderoso.

An Analysis of the Rise and Fall of the AA-MAS Policy

Science.gov (United States)

Lazarus, Sheryl S.; Thurlow, Martha L.; Ysseldyke, James E.; Edwards, Lynn M.

2015-01-01

In 2005, to address concerns about students who might fall in the "gap" between the regular assessment and the alternate assessment based on alternate achievement standards (AA-AAS), the U.S. Department of Education announced that states could develop alternate assessments based on modified achievement standards (AA-MAS). This article…

Microscopic structural analysis of fractured silk fibers from Bombyx mori and Samia cynthia ricini using 13C CP/MAS NMR with a 1 mm microcoil MAS NMR probehead

KAUST Repository

Yamauchi, Kazuo

2010-07-01

Conformational changes have been studied in silk fibers from the domestic silkworm Bombyx mori and a wild silkworm Samia cynthia ricini as a result of fractured by stretching. About 300 samples consisting of only the fractured regions of [1-13C]Ala or [1-13C]Gly labeled silk fibers were collected and observed by 13C CP/MAS NMR spectra. The total amount of these fractured fibers is only about 1 mg and therefore we used a home-built 1 mm microcoil MAS NMR probehead. A very small increase in the fraction of random coil was noted for the alanine regions of both silk fibroins and for the glycine region of B. mori silk fibroin. However, there is no difference in the spectra before and after fractured for the glycine region of S. c. ricini silk fibroin. Thus, the influence of fracture occurs exclusively at the Ala region for S. c. ricini. The relationship between sequence, fracture and structure is discussed. © 2010 Elsevier Inc. All rights reserved.

77 FR 43084 - Multiple Award Schedule (MAS) Program Continuous Open Season-Operational Change

Science.gov (United States)

2012-07-23

... (GSA), Federal Acquisition Service (FAS) intends to institute a Demand Based Model (DBM) designed to... will restore and maintain the MAS program's value to Federal agencies as a streamlined acquisition... adding innovative solutions, improving pricing and simplifying the buying experience. DATES: This change...

Personālā datora sistēmas bloka vides snieguma novērtējums un ekodizaina analīze

OpenAIRE

Šteina, Māra

2009-01-01

Maģistra darba „Personālā datora sistēmas bloka vides snieguma novērtējums un ekodizaina analīze” pamatā ir biroja datora sistēmas bloka ietekmes uz vidi novērtējums visā tā dzīves cikla laikā, izvērtējot arī lietotāju un iesaistīto pušu nozīmi. Darbs sastāv no divām daļām – teorētiskās un praktiskās. Pirmā daļa ir teorētiskajā daļa, kurā autore apskatīja pieejamos literatūras avotus un citu autoru darbus, izvērtējot tēmas aktualitāti, galvenās problēmas un to risinājumus. Otrā daļa ...

Fast fundamental frequency estimation

DEFF Research Database (Denmark)

Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

2017-01-01

Modelling signals as being periodic is common in many applications. Such periodic signals can be represented by a weighted sum of sinusoids with frequencies being an integer multiple of the fundamental frequency. Due to its widespread use, numerous methods have been proposed to estimate the funda...

Numerical prediction of the natural frequency of an Oscillating Water Column operating under resonant conditions

Directory of Open Access Journals (Sweden)

Marco Torresi

2016-12-01

Full Text Available Among the different technologies developed in order to harness wave energy, the Oscillating Water Column devices are the most accredited for an actual diffusion. Recently, Boccotti has patented the REWEC1 (REsonant sea Wave Energy Converter solution 1, a submerged breakwater that performs an active coast protection, embedding an Oscillating Water Column device, which is capable of operating under resonant conditions with that sea state, which gives the highest yearly energy contribution. The REWEC1 dynamic behavior can be approximated by means of a mass-spring-damper system. According to this approximation, a criterion for evaluating the oscillating natural frequency of the REWEC1 has been derived. This criterion has been validated against both experimental results and computational fluid dynamics simulations, performed on a REWEC1 laboratory-scale model. The numerical simulations have shown a good agreement between measurements and predictions.

Ceļu satiksmes drošības direkcijas (CSDD) sociālo reklāmas kampaņu klipu semiotiskā analīze (2003. - 2013.)

OpenAIRE

Lapinska, Ginta

2014-01-01

Bakalaura darba tēma ir „Ceļu satiksmes drošības direkcijas (CSDD) sociālo reklāmas kampaņu klipu semiotiskā analīze (2003. - 2013.)”. CSDD reklāmas gadu gaitā ir pārliecinājušas reklāmas industriju un auditoriju, tāpēc būtiski ir noskaidrot, kādi ir izmantotie semiotiskie elementi un kā to izmantojums gadu gaitā ir mainījies. Darba mērķis ir izpētīt vienojošos semiotiskos elementus CSDD reklāmas kampaņu klipos no 2003.-2013. gadam. Teorētiskajā daļā aplūkotas tēmas: reklāmas, kampaņas ...

Who bears the burden of international taxation? Evidence from cross-border M&As

NARCIS (Netherlands)

Huizinga, H.P.; Voget, J.; Wagner, W.B.

2012-01-01

Cross-border M&As can trigger additional taxation of the target's income in the form of non-resident dividend withholding taxes and acquirer-country corporate income taxation. This paper finds that this additional international taxation is fully capitalized into lower takeover premiums. In contrast,

TOKSISITAS LETAL MOLUSKISIDA NIKLOSAMIDA PADA BENIH IKAN MAS (Cyprinus carpio

Directory of Open Access Journals (Sweden)

Yosmaniar Yosmaniar

2009-04-01

Full Text Available Penggunaan moluskisida untuk menanggulangi hama dalam budidaya tanaman padi yang semakin meningkat berpotensi mencemari lingkungan perairan, karena mengandung residu dari bahan aktifnya. Moluskisida niklosamida (C13H8Cl2N2O4 merupakan bahan aktif pestisida yang digunakan untuk memberantas hama keong mas atau siput murbei (Pomacea sp. di sawah. Dengan demikian, bahan tersebut memiliki potensi untuk mencemari lahan tempat usaha budidaya ikan. Penelitian ini bertujuan untuk mengetahui potensi toksisitas akut niklosamida terhadap benih ikan mas (Cyprinus carpio yang ditunjukkan oleh nilai Median Lethal Concentration (LC50 24, 48, dan 96 jam. Penelitian dilakukan di Instalasi Riset Lingkungan Perikanan Budidaya dan Toksikologi, Cibalagung-Bogor. Menggunakan ikan mas dengan bobot individu 2,47 ± 0,13 g. Moluskisida yang digunakan mengandung bahan aktif niklosamida 250g/L. Wadah pengujian berupa 21 unit akuarium kaca berukuran 40 cm x 20 cm x 20 cm yang dilengkapi aerasi serta saluran pemasukan dan pengeluaran. Jumlah ikan uji setiap wadah 10 ekor dengan peubah yang diukur adalah mortalitas ikan. Selama penelitian ikan tidak diberi makan. Tahapan penelitian terdiri atas penentuan nilai ambang atas-bawah, nilai lethal time dan LC50 -24, 48, 72, dan 96 jam. Data diolah dengan analisis probit program LC50. Hasil penelitian menunjukkan bahwa nilai LC50-24, 48, 72, dan 96 jam terhadap benih ikan mas adalah 0,8012 (0,7140—0,8990; 0,5999 (0,5356—0,6719; 0,4511 (0,4067—0,5004; dan 0,3849 mg/L (0,3684—0,4061. Hal ini menunjukkan niklosamida termasuk pestisida yang memiliki toksisitas sangat tinggi (golongan A. The use of molluscicide in aquatic as well as in terresterial agro ecosystem without properly controlled may produce detrimental effects on freshwater fisheries. Molluscicide utilization for golden apple snail (Pomacea sp. control in rice field has increased. The ingredient potencially has a possibility to pollute aquaculture water. The

Veikala „Dīvāni un Dīvāni” reklāmas analīze un pilnveidošanas iespējas.

OpenAIRE

Alsiņa, Madara

2013-01-01

Bakalaura darba tēma „Veikala „Dīvāni un Dīvāni” reklāmas analīze un pilnveidošanas iespējas”. Bakalaura darba mērķis ir, pamatojoties uz teorijā gūtajām atziņām par reklāmu, izanalizēt veikala „Dīvāni un Dīvāni” reklāmas pasākumus, to stiprās un vājās puses, novērtēt reklāmas komunikatīvo efektivitāti, kā arī izstrādāt priekšlikumus veikala „Dīvāni un Dīvāni” reklāmas pilnveidošanai. Pirmajā darba daļā tiek apskatīti reklāmas kā mārketinga komunikāciju elementa teorētiskie aspekti – ...

On the elimination of numerical Cerenkov radiation in PIC simulations

International Nuclear Information System (INIS)

Greenwood, Andrew D.; Cartwright, Keith L.; Luginsland, John W.; Baca, Ernest A.

2004-01-01

Particle-in-cell (PIC) simulations are a useful tool in modeling plasma in physical devices. The Yee finite difference time domain (FDTD) method is commonly used in PIC simulations to model the electromagnetic fields. However, in the Yee FDTD method, poorly resolved waves at frequencies near the cut off frequency of the grid travel slower than the physical speed of light. These slowly traveling, poorly resolved waves are not a problem in many simulations because the physics of interest are at much lower frequencies. However, when high energy particles are present, the particles may travel faster than the numerical speed of their own radiation, leading to non-physical, numerical Cerenkov radiation. Due to non-linear interaction between the particles and the fields, the numerical Cerenkov radiation couples into the frequency band of physical interest and corrupts the PIC simulation. There are two methods of mitigating the effects of the numerical Cerenkov radiation. The computational stencil used to approximate the curl operator can be altered to improve the high frequency physics, or a filtering scheme can be introduced to attenuate the waves that cause the numerical Cerenkov radiation. Altering the computational stencil is more physically accurate but is difficult to implement while maintaining charge conservation in the code. Thus, filtering is more commonly used. Two previously published filters by Godfrey and Friedman are analyzed and compared to ideally desired filter properties

Klientu attiecību pārvaldības sistēmas izveide autoservisam

OpenAIRE

Jaunzems, Ģirts

2012-01-01

Diplomdarba tēma ir Klientu attiecību pārvaldības sistēmas izveide autoservisam. Tā mērķis ir izstrādāt un ieviest pielāgotu klientu attiecību pārvaldības sistēmu nelielam autoservisam, tādējādi atvieglojot klientu un viņu darbības vēstures uzskaiti. Lai sasniegtu diplomdarba mērķi, darba autors izpētīja teorētiskos informācijas avotus, salīdzināja divas klientu pārvaldības sistēmas, kā arī izstrādāja sistēmu konkrētam uzņēmumam, veicot arī tās izmaksu analīzi. Diplomdarbā ir secināts, ...

Mas-related G protein coupled receptor-X2: A potential new target for modulating mast cell-mediated allergic and inflammatory diseases.

Science.gov (United States)

Ali, Hydar

2016-12-01

Mast cells (MCs) are tissue resident immune cells that are best known for their roles in allergic and inflammatory diseases. In addition to the high affinity IgE receptor (FcεRI), MCs express numerous G protein coupled receptors (GPCRs), which are the most common targets of drug therapy. Neurokinin 1 receptor (NK-1R) is expressed on MCs and contributes to IgE and non-IgE-mediated responses in mice. Although NK-1R antagonists are highly effective in modulating experimental allergic and inflammatory responses in mice they lack efficacy in humans. This article reviews recent findings that demonstrate that while neuropeptides (NPs) activate murine MCs via NK-1R and Mas related G protein coupled receptor B2 (MrgprB2), they activate human MCs via Mas-related G protein coupled receptor X2 (MRGPRX2). Interestingly, conventional NK-1R antagonists have off-target activity against mouse MrgprB2 but not human MRGPRX2. These findings suggest that the failure to translate studies with NK-1R antagonists from in vivo mouse studies to the clinic likely reflects their lack of effect on human MRGPRX2. A unique feature of MRGPRX2 that distinguishes it from other GPCRs is that it is activated by a diverse group of ligands that include; neuropeptides, cysteine proteases, antimicrobial peptides and cationic proteins released from activated eosinophils. Thus, the development of small molecule MRGPRX2-specific antagonists or neutralizing antibodies may provide new targets for the treatment of MC-mediated allergic and inflammatory diseases.

KEBIJAKAN INVESTASI ASING BIDANG PERTAMBANGAN DI KABUPATEN POHUWATO PROVINSI GORONTALO KEBIJAKAN INVESTASI ASING BIDANG PERTAMBANGAN DI KABUPATEN POHUWATO PROVINSI GORONTALO KEBIJAKAN INVESTASI ASING BIDANG PERTAMBANGAN DI KABUPATEN POHUWATO PROVINSI GORONTALO KASUS PT. PANI DHARMA MAS KASUS PT. PANI DHARMA MAS KASUS PT. PANI DHARMA MAS

OpenAIRE

PUYO, AJENG MAWADDAH PUYO AJENG MAWADDAH PUYO AJENG MAWADDAH

2016-01-01

2016 AJENG MAWADDAH PUYO, E 131 12 003, "Kebijakan Investasi Asing Dalam Bidang Pertambangan di Kabupaten Pohuwato Provinsi Gorontalo Kasus PT. Pani Dharma MAS", dibawah bimbingan Dr. H. Adi Suryadi B., MA selaku pembimbing I dan Pusparida Syahdan. S.sos., MSI, Departemen Ilmu Hubungan internasional, Fakultas Ilmu Sosial dan Ilmu Politik, Universitas Hasanuddin. Penelitian ini bertujuan untuk mengetahui peran stakeholders dalam perumusan kebijakan investasi asing da...

Acceptance Test Report for the Modular Automation System (MAS) Manufactured by Honeywell Inc

International Nuclear Information System (INIS)

ANDERSON, D.L.

2000-01-01

This document details the performance of the acceptance test of the Honeywell MAS Control System for equipment to be installed in gloveboxes HA-20MB and HA-211 at a later date. Equipment that was anticipated included 6 stabilization furnaces, only three and their associated equipment were installed

Estimating surface fluxes using eddy covariance and numerical ogive optimization

DEFF Research Database (Denmark)

Sievers, J.; Papakyriakou, T.; Larsen, Søren Ejling

2015-01-01

Estimating representative surface fluxes using eddy covariance leads invariably to questions concerning inclusion or exclusion of low-frequency flux contributions. For studies where fluxes are linked to local physical parameters and up-scaled through numerical modelling efforts, low-frequency con......Estimating representative surface fluxes using eddy covariance leads invariably to questions concerning inclusion or exclusion of low-frequency flux contributions. For studies where fluxes are linked to local physical parameters and up-scaled through numerical modelling efforts, low...

Analytical and numerical calculations of resistive wall impedances for thin beam pipe structures at low frequencies

Energy Technology Data Exchange (ETDEWEB)

Niedermayer, U., E-mail: u.niedermayer@gsi.de [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany); Boine-Frankenheim, O. [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

2012-09-21

The resistive wall impedance is one of the main sources for beam instabilities in synchrotrons and storage rings. The fast ramped SIS18 synchrotron at GSI and the projected SIS100 synchrotron for FAIR both employ thin (0.3 mm) stainless steel beam pipes in order to reduce eddy current effects. The lowest betatron sidebands are at about 100 kHz, which demands accurate impedance predictions in the low frequency (LF) range where the beam pipe and possibly also the structures behind the pipe are the dominating impedance sources. The longitudinal and transverse resistive wall impedances of a circular multi-layer pipe are calculated analytically using the field matching technique. We compare the impedances obtained from a radial wave model, which corresponds to the setup used in bench measurements, with the axial wave model, which corresponds to an actual beam moving with relativistic velocity. For thin beam pipes the induced wall current and the corresponding shielding properties of the pipe are important. In both models the wall current is obtained analytically. The characteristic frequencies for the onset of the wall current are calculated from equivalent lumped element circuits corresponding to the radial model. For more complex structures, like the SIS100 beam pipe, we use a numerical method, in which the impedance is obtained from the total power loss. The method is validated by the analytic expressions for circular beam pipes.

Effectiveness of FitoMas-E in the cultivation of chickpea under two soil moisture levels

Directory of Open Access Journals (Sweden)

Yanitza Meriño Hernández

2018-01-01

Full Text Available To evaluate the effect of FitoMas-E on the performance of the chickpea, in conditions of drought stress, was the objective of this investigation. An experiment was conducted in the Intensive Garden "Río de Guisa" in the municipality of Guisa during the period from November to February 2014. Four treatments were applied, distributed in a randomized block design with three repetitions, on a "Pardo mullido grisaceo" soil, comparing the application of FitoMas-E under two soil moisture regimes, with and without water stress. The yield of grain and its components were evaluated at the time of harvest maturity, to analyze the responses of these variables to the treatments applied. An analysis of variance was performed using the statistical package STASTISTICA version 8.0 for Windows and the means of the treatments were compared using the Tukey Multiple Range test. The variables that showed a greater response to the treatments imposed were the number of legumes per plant, number of seeds per plant, the mass of 100 seeds and the yield of grain, which ranged between 0.9 and 0.93 t ha-1 for the treatments 2 and 4 respectively. The results obtained in this research showed that the chickpea crop achieved the best productive indicators when the plants were under water stress conditions and received the application of FitoMas-E.

Variable temperature 127I MAS NMR of β-AgI

International Nuclear Information System (INIS)

Wagner, G.W.

1991-01-01

Variable temperature 127 I MAS NMR of β-AgI powder, measured from 123 to 413 K is sensitive to Ag + diffusion through the iodine lattice. In low temperature spectra, the iodine ions appear to be in nearly static environments in agreement with the low temperature crystal structure. However, at higher temperatures, substantial broadening of the central transition linewidth is consistent with the presence of two types of Ag + diffusion with activation energies of 0.17 and 0.0080 eV. (author). 15 refs.; 5 figs.; 1 tab

Can Memory Assessment Services (MAS) in England be categorized? A national survey.

Science.gov (United States)

Chrysanthaki, T; Fernandes, B; Smith, S; Black, N

2017-12-01

The effectiveness and efficiency of memory assessment services (MASs) is unknown. Our aim was to determine if a typology can be constructed, based on shared structural and process characteristics, as a basis for a non-randomized evaluation of their effectiveness and cost-effectiveness. Survey of random sample of 73 MASs in 2015; comparison of characteristics and investigation of inter-correlation. It was not possible to group characteristics to form the basis of a typology of MASs. However, there was considerable variation in staff numbers (20-fold), new patients per whole-time equivalent (WTE) staff (20-fold), skill mix and the nurse:doctor ratio (1-10). The operational performance also varied: first appointments (50-120 minutes); time for first follow-up (2-12 weeks); frequency of follow-up in first year (1-5). These differences were not associated with the number of new patients per WTE staff or the accreditation status of the MAS. Post diagnosis, all MASs provided pharmacological treatment but the availability of non-pharmacological support varied, with half providing none or only one intervention while others providing four or more. In the absence of any clear typology, evaluation of MASs will need to focus on the impact of individual structural and process characteristics on outcomes. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Food Waste Composting Study from Makanan Ringan Mas

Science.gov (United States)

Kadir, A. A.; Ismail, S. N. M.; Jamaludin, S. N.

2016-07-01

The poor management of municipal solid waste in Malaysia has worsened over the years especially on food waste. Food waste represents almost 60% of the total municipal solid waste disposed in the landfill. Composting is one of low cost alternative method to dispose the food waste. This study is conducted to compost the food waste generation in Makanan Ringan Mas, which is a medium scale industry in Parit Kuari Darat due to the lack knowledge and exposure of food waste recycling practice. The aim of this study is to identify the physical and chemical parameters of composting food waste from Makanan Ringan Mas. The physical parameters were tested for temperature and pH value and the chemical parameter are Nitrogen, Phosphorus and Potassium. In this study, backyard composting was conducted with 6 reactors. Tapioca peel was used as fermentation liquid and soil and coconut grated were used as the fermentation bed. Backyard composting was conducted with six reactors. The overall results from the study showed that the temperature of the reactors were within the range which are from 30° to 50°C. The result of this study revealed that all the reactors which contain processed food waste tend to produce pH value within the range of 5 to 6 which can be categorized as slightly acidic. Meanwhile, the reactors which contained raw food waste tend to produce pH value within the range of 7 to 8 which can be categorized as neutral. The highest NPK obtained is from Reactor B that process only raw food waste. The average value of Nitrogen is 48540 mg/L, Phosphorus is 410 mg/L and Potassium is 1550 mg/L. From the comparison with common chemical fertilizer, it shows that NPK value from the composting are much lower than NPK of the common chemical fertilizer. However, comparison with NPK of organic fertilizer shown only slightly difference value in NPK.

Experimental and Numerical Analysis of Hydroformed Tubular Materials for Superconducting Radio Frequency (SRF) Cavities

Science.gov (United States)

Kim, Hyun Sung

Superconducting radio frequency (SRF) cavities represent a well established technology benefiting from some 40 years of research and development. An increasing demand for electron and positron accelerators leads to a continuing interest in improved cavity performance and fabrication techniques. Therefore, several seamless cavity fabrication techniques have been proposed for eliminating the multitude of electron-beam welded seams that contribute to the introduction of performance-reducing defects. Among them, hydroforming using hydraulic pressure is a promising fabrication technique for producing the desired seamless cavities while at the same time reducing manufacturing cost. This study focused on experimental and numerical analysis of hydroformed niobium (Nb) tubes for the successful application of hydroforming technique to the seamless fabrication of multi-cell SRF cavities for particle acceleration. The heat treatment, tensile testing, and bulge testing of Cu and Nb tubes has been carried out to both provide starting data for models of hydroforming of Nb tube into seamless SRF cavities. Based on the results of these experiments, numerical analyses using finite element modeling were conducted for a bulge deformation of Cu and Nb. In the experimental part of the study samples removed from representative tubes were prepared for heat treatment, tensile testing, residual resistance ratio (RRR) measurement, and orientation imaging electron microscopy (OIM). After being optimally heat treated Cu and Nb tubes were subjected to hydraulic bulge testing and the results analyzed. For numerical analysis of hydroforming process, two different simulation approaches were used. The first model was the macro-scale continuum model using the constitutive equations (stress-strain relationship) as an input of the simulation. The constitutive equations were obtained from the experimental procedure including tensile and tube bulge tests in order to investigate the influence of loading

The MAS Six Years in Power in Bolivia

Directory of Open Access Journals (Sweden)

Ton Salman

2012-04-01

Full Text Available Review Essay of:– The Rise of Evo Morales and the MAS, by Sven Harten. London/New York: Zed Books, 2011.– Evo Morales and the Movimiento al Socialismo in Bolivia; The First Term in Context, edited by Adrian J. Pearce. London, Institute for the Study of the Americas, 2011.– El estado de derecho como tiranía, by Luis Tapia. La Paz: CIDES/UMSA, 2011.– From Rebellion to Reform in Bolivia: Class Struggle, Indigenous Liberation and the Politics of Evo Morales, by Jeffery R. Webber. Chicago: Haymarket Books, 2011.– La democracia desde los márgenes: Transformaciones en el campo político boliviano, by María Teresa Zegada, with Claudia Arce, Gabriela Canedo and Alber Quispe. La Paz: Muela del Diablo Editores/CLACSO, 2011.

Multi-Robot Remote Interaction with FS-MAS

Directory of Open Access Journals (Sweden)

Yunliang Jiang

2013-02-01

Full Text Available The need to reduce bandwidth, improve productivity, autonomy and the scalability in multi-robot teleoperation has been recognized for a long time. In this article we propose a novel finite state machine mobile agent based on the network interaction service model, namely FS-MAS. This model consists of three finite state machines, namely the Finite State Mobile Agent (FS-Agent, which is the basic service module. The Service Content Finite State Machine (Content-FS, using the XML language to define workflow, to describe service content and service computation process. The Mobile Agent computation model Finite State Machine (MACM-FS, used to describe the service implementation. Finally, we apply this service model to the multi-robot system, the initial realization completing complex tasks in the form of multi-robot scheduling. This demonstrates that the robot has greatly improved intelligence, and provides a wide solution space for critical issues such as task division, rational and efficient use of resource and multi-robot collaboration.

KERAGAAN PERTUMBUHAN BENIH IKAN MAS (Cyprinus carpio STRAIN MAJALAYA, LOKAL BOGOR DAN RAJADANU DI KOLAM CIJERUK, BOGOR-JAWA BARAT

Directory of Open Access Journals (Sweden)

Otong Zenal Arifin

2016-11-01

Full Text Available Penelitian ini bertujuan untuk mendapatkan strain ikan mas yang memiliki keragaan pertumbuhan yang baik sebagai spesies kandidat untuk program seleksi. Tiga strain ikan mas (majalaya, lokal Bogor, dan rajadanu dipelihara dalam jaring yang diletakkan di kolam Instalasi Penelitian Cijeruk, Bogor selama 6 minggu. Hasil penelitian menunjukkan bahwa tidak ada perbedaan nyata untuk parameter pertambahan bobot dan sintasan dari 3 strain ikan mas yang diuji, sedangkan untuk pertambahan panjang individual (mm per bulan ada perbedaan yang sangat nyata (P<0,05. Strain ikan mas rajadanu memiliki pertambahan panjang terbaik (16,0 ± 1,41 dan berbeda dengan majalaya (10,3 ± 4,50 serta lokal (10,8 ± 2,06. Objective of this study is to produce good performance of common carp by comparing three promising strains majalaya, local, and rajadanu. The study was carry out using floating net cages placed in earthen pond at The Cijeruk Germ Plasm Research Station. During the study, growth and survival rate were observed were observed for six weeks. The results indicated there was no significant difference for growth of weight and survival rate. However, growth of standard length was significantly different (P<0.05. Rajadanu made the best growth of standard length (16.0 ± 1.41 and was different from majalaya (10.3 ± 4.50 and local strain (10.8 ± 2.06.

One-dimensional numerical simulations of the low-frequency electric fields in the CRIT 1 and CRIT 2 rocket experiments

International Nuclear Information System (INIS)

Bolin, O.; Brenning, N.

1992-04-01

One-dimensional numerical particle simulations have been performed of the ionospheric barium injection experiments CRIT 1 and CRIT 2, using a realistic model for the shape and the time development of the injected neutral cloud. The electrodynamic response of the ionosphere to these injections is modelled by magnetic-field-aligned currents, using the concept of Alfven conductivity. The results shows very good agreement with the CRIT data, especially concerning the low-frequency oscillations that were seen after the initial phase of the injections. The shapes, amplitudes, phases, and decay times of the electric fields are all very close to the values measured in the CRIT experiments. (au)

Frequency spirals

International Nuclear Information System (INIS)

Ottino-Löffler, Bertrand; Strogatz, Steven H.

2016-01-01

We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

Frequency spirals

Energy Technology Data Exchange (ETDEWEB)

Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

2016-09-15

We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

Angiotensin (1-7) ameliorates the structural and biochemical alterations of ovariectomy-induced osteoporosis in rats via activation of ACE-2/Mas receptor axis.

Science.gov (United States)

Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

2017-05-23

The local and systemic renin angiotensin system (RAS) influences the skeletal system micro-structure and metabolism. Studies suggested angiotensin 1-7 (Ang(1-7)) as the beneficial RAS molecule via Mas receptor activation. This study examines the function of Ang(1-7) in bone micro-architecture and metabolism in an ovariectomized (OVX) rodent model of osteoporosis. OVX rats showed structural and bone metabolic degeneration in parallel with suppressed expressions of the angiotensin converting enzyme-2 (ACE-2)/Ang(1-7)/Mas components. The infusion of Ang(1-7) markedly alleviated the altered bone metabolism and significantly enhanced both trabecular (metaphyseal) and cortical (metaphyseal-diaphyseal) morphometry. Urinary and bones minerals were also improved in OVX rats by Ang(1-7). The infusion of the heptapeptide enhanced ACE-2/Mas receptor expressions, while down-regulated AngII, ACE, and AngII type-1 receptor (AT1R) in OVX animals. Moreover, Ang(1-7) markedly improved osteoprotegerin (OPG) and lowered receptor activator NF-κB ligand (RANKL) expressions. The defensive properties of Ang(1-7) on bone metabolism, structure and minerals were considerably eradicated after blockage of Mas receptor with A-779. Ang(1-7)-induced up-regulated ACE-2/Ang(1-7)/Mas cascade and OPG expressions were abolished and the expressions of ACE/AngII/AT1R and RANKL were provoked by A-779. These findings shows for the first time the novel valuable therapeutic role of Ang(1-7) on bone health and metabolism through the ACE-2/Mas cascade.

Numerical Simulation of Spheroidization Process of TiAl Alloy Powders in Radio Frequency Plasma

Directory of Open Access Journals (Sweden)

ZHU Langping

2017-06-01

Full Text Available A numerical simulation method was used to study the radio frequency plasma spheroidization process of TiAl alloy powder. The effects of velocity field and temperature field on the motion trajectory and mass change of TiAl alloy powder with different particle size were analyzed.The results show that the temperature of powder particles increases rapidly under high temperature plasma, surface evaporation cause the reduction of particle size, and particles with small size tend to evaporate quickly. The motion trajectory of particles with different sizes in the lower end of the cooling tube is different obviously, small particles tend to enter the air outlet,while the larger particles are easy to fall down to the bottom of the cooling tube to be collected. Increasing air flow rate can improve the velocity of air flow in the spheroidizing system, causing larger particles to be taken away by the air, resulting in yield reduction. The simulation results of TiAl alloy powder spheroidization are close to the experimental results refer to parameters such as powder size distribution, average particle size and powder yield, and the model is in good accordance with the actual process of the spheroidization.

HR-MAS NMR for rapid identification of illicit substances in tablets and Blotter papers seized by Police Department

International Nuclear Information System (INIS)

Souza, Luciano F.; Vieira, Tarcísio S.; Lião, Luciano M.; Alcantara, Glaucia B.

2016-01-01

Illicit substances found in blotter papers and tablets seized by police are traditionally identified and characterized from extracts of these materials. However, the procedures involved in extraction stages can result in artifacts and even contamination of the samples to be analyzed. On the other hand, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) is a technique that requires no pretreatment steps, enabling direct analysis of the material, including the analysis of new illegal synthetic psychoactive substances. This study presents and discusses applications of the HR-MAS NMR in the analysis of tablets and blotter papers seized. Additional analysis in solution of the extracts of these materials was performed to compare the obtained spectral resolution signals. The results demonstrated that the HR-MAS NMR allowed the rapid identification of 3,4-methylenedioxy-N-methylcathinone (methylone), 4-methylmethcathinone (mephedrone), 2,5-dimethoxy-4-bromoamphetamine (DOB) and 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2- methoxyphenyl)methyl]ethanamine (25B-NBOMe) in samples of tablets and blotter papers seized in Goiás State, Brazil. (author)

HR-MAS NMR for rapid identification of illicit substances in tablets and Blotter papers seized by Police Department

Energy Technology Data Exchange (ETDEWEB)

Souza, Luciano F.; Vieira, Tarcísio S.; Lião, Luciano M., E-mail: lucianoliao@ufg.br [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Química; Alcantara, Glaucia B. [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Instituto de Química

2016-07-01

Illicit substances found in blotter papers and tablets seized by police are traditionally identified and characterized from extracts of these materials. However, the procedures involved in extraction stages can result in artifacts and even contamination of the samples to be analyzed. On the other hand, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) is a technique that requires no pretreatment steps, enabling direct analysis of the material, including the analysis of new illegal synthetic psychoactive substances. This study presents and discusses applications of the HR-MAS NMR in the analysis of tablets and blotter papers seized. Additional analysis in solution of the extracts of these materials was performed to compare the obtained spectral resolution signals. The results demonstrated that the HR-MAS NMR allowed the rapid identification of 3,4-methylenedioxy-N-methylcathinone (methylone), 4-methylmethcathinone (mephedrone), 2,5-dimethoxy-4-bromoamphetamine (DOB) and 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2- methoxyphenyl)methyl]ethanamine (25B-NBOMe) in samples of tablets and blotter papers seized in Goiás State, Brazil. (author)

High-frequency modulation of ion-acoustic waves.

Science.gov (United States)

Albright, N. W.

1972-01-01

A large amplitude, high-frequency electromagnetic oscillation is impressed on a nonrelativistic, collisionless plasma from an external source. The frequency is chosen to be far from the plasma frequency (in fact, lower). The resulting electron velocity distribution function strongly modifies the propagation of ion-acoustic waves parallel to the oscillating electric field. The complex frequency is calculated numerically.

Gaming Frequency and Academic Performance

Science.gov (United States)

Ip, Barry; Jacobs, Gabriel; Watkins, Alan

2008-01-01

There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency--measured as the…

Effects of Raman scattering in quantum state-preserving frequency conversion

DEFF Research Database (Denmark)

Friis, Søren Michael Mørk; Andersen, Lasse Mejling; Castaneda, Mario A. Usuga

2014-01-01

We analyse frequency conversion by Bragg scattering numerically including Raman scattering. The frequency configuration that performs the best under influence of Raman noise results in 95% conversion over a 3.25 THz bandwidth with a 2.5-dB noise figure.......We analyse frequency conversion by Bragg scattering numerically including Raman scattering. The frequency configuration that performs the best under influence of Raman noise results in 95% conversion over a 3.25 THz bandwidth with a 2.5-dB noise figure....

Characterizing crystal disorder of trospium chloride: a comprehensive,(13) C CP/MAS NMR, DSC, FTIR, and XRPD study.

Science.gov (United States)

Urbanova, Martina; Sturcova, Adriana; Brus, Jiri; Benes, Hynek; Skorepova, Eliska; Kratochvil, Bohumil; Cejka, Jan; Sedenkova, Ivana; Kobera, Libor; Policianova, Olivia; Sturc, Antonin

2013-04-01

Analysis of C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and X-ray powder diffraction data of trospium chloride (TCl) products crystallized from different mixtures of water-ethanol [φ(EtOH) = 0.5-1.0] at various temperatures (0°C, 20°C) and initial concentrations (saturated solution, 30%-50% excess of solvent) revealed extensive structural variability of TCl. Although (13) C CP/MAS NMR spectra indicated broad variety of structural phases arising from molecular disorder, temperature-modulated DSC identified presence of two distinct components in the products. FTIR spectra revealed alterations in the hydrogen bonding network (ionic hydrogen bond formation), whereas the X-ray diffraction reflected unchanged unit cell parameters. These results were explained by a two-component character of TCl products in which a dominant polymorphic form is accompanied by partly separated nanocrystalline domains of a secondary phase that does not provide clear Bragg reflections. These phases slightly differ in the degree of molecular disorder, in the quality of crystal lattice and hydrogen bonding network. It is also demonstrated that, for the quality control of such complex products, (13) C CP/MAS NMR spectroscopy combined with factor analysis (FA) can satisfactorily be used for categorizing the individual samples: FA of (13) C CP/MAS NMR spectra found clear relationships between the extent of molecular disorder and crystallization conditions. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1235-1248, 2013. Copyright © 2013 Wiley Periodicals, Inc.

Frequency-agile gyrotron for electron decoupling and pulsed dynamic nuclear polarization

Science.gov (United States)

Scott, Faith J.; Saliba, Edward P.; Albert, Brice J.; Alaniva, Nicholas; Sesti, Erika L.; Gao, Chukun; Golota, Natalie C.; Choi, Eric J.; Jagtap, Anil P.; Wittmann, Johannes J.; Eckardt, Michael; Harneit, Wolfgang; Corzilius, Björn; Th. Sigurdsson, Snorri; Barnes, Alexander B.

2018-04-01

We describe a frequency-agile gyrotron which can generate frequency-chirped microwave pulses. An arbitrary waveform generator (AWG) within the NMR spectrometer controls the microwave frequency, enabling synchronized pulsed control of both electron and nuclear spins. We demonstrate that the acceleration of emitted electrons, and thus the microwave frequency, can be quickly changed by varying the anode voltage. This strategy results in much faster frequency response than can be achieved by changing the potential of the electron emitter, and does not require a custom triode electron gun. The gyrotron frequency can be swept with a rate of 20 MHz/μs over a 670 MHz bandwidth in a static magnetic field. We have already implemented time-domain electron decoupling with dynamic nuclear polarization (DNP) magic angle spinning (MAS) with this device. In this contribution, we show frequency-swept DNP enhancement profiles recorded without changing the NMR magnet or probe. The profile of endofullerenes exhibits a DNP profile with a <10 MHz linewidth, indicating that the device also has sufficient frequency stability, and therefore phase stability, to implement pulsed DNP mechanisms such as the frequency-swept solid effect. We describe schematics of the mechanical and vacuum construction of the device which includes a novel flanged sapphire window assembly. Finally, we discuss how commercially available continuous-wave gyrotrons can potentially be converted into similar frequency-agile high-power microwave sources.

Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists.

Science.gov (United States)

Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P

2015-12-15

The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of the structural changes by Raman and {sup 13}C CP/MAS NMR spectroscopy on native corn starch with plasticizers

Energy Technology Data Exchange (ETDEWEB)

Cozar, O. [Academy of Romanian Scientists, Splaiul Independentei 54, 050094, Bucharest, Romania and National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch (Romania); Filip, C.; Tripon, C. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Cioica, N.; Coţa, C.; Nagy, E. M. [National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch, RO-400458 Cluj-Napoca (Romania)

2013-11-13

The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and {sup 13}C CP/MAS NMR spectroscopy. The presence of both amorphous and crystalline structural phases was evidenced in pure native corn starch and also in the samples containing plasticizers. Among the crystalline starch structures, the A- and V- types were suggested by CP/MAS NMR spectra.

Percutaneous dilational tracheostomy (PDT) and prevention of blood aspiration with superimposed high-frequency jet ventilation (SHFJV) using the tracheotomy-endoscope (TED): results of numerical and experimental simulations.

Science.gov (United States)

Nowak, Andreas; Langebach, Robin; Klemm, Eckart; Heller, Winfried

2012-04-01

We describe an innovative computer-based method for the analysis of gas flow using a modified airway management technique to perform percutaneous dilatational tracheotomy (PDT) with a rigid tracheotomy endoscope (TED). A test lung was connected via an artificial trachea with the tracheotomy endoscope and ventilated using superimposed high-frequency jet ventilation. Red packed cells were instilled during the puncture phase of a simulated percutaneous tracheotomy in a trachea model and migration of the red packed cells during breathing was continuously measured. Simultaneously, the calculation of the gas-flow within the endoscope was numerically simulated. In the experimental study, no backflow of blood occurred during the use of superimposed high-frequency jet ventilation (SHFJV) from the trachea into the endoscope nor did any transportation of blood into the lower respiratory tract occur. In parallel, the numerical simulations of the openings of TED show almost positive volume flows. Under the conditions investigated there is no risk of blood aspiration during PDT using the TED and simultaneous ventilation with SHFJV. In addition, no risk of impairment of endoscopic visibility exists through a backflow of blood into the TED. The method of numerical simulation offers excellent insight into the fluid flow even under highly transient conditions like jet ventilation.

The flexibility of SIMPSON and SIMMOL for numerical simulations in solid-and liquid-state NMR spectroscopy

International Nuclear Information System (INIS)

Vosegaard, T.; Malmendal, A.; Nielsen, N.C.

2002-01-01

Addressing the need for numerical simulations in the design and interpretation of advanced solid- and liquid-state NMR experiments, we present a number of novel features for numerical simulations based on the SIMPSON and SIMMOL open source software packages. Major attention is devoted to the flexibility of these Tcl-interfaced programs for numerical simulation of NMR experiments being complicated by demands for efficient powder averaging, large spin systems, and multiple-pulse rf irradiation. These features are exemplified by fast simulation of second-order quadrupolar powder patterns using crystallite interpolation, analysis of rotary resonance triple-quantum excitation for quadrupolar nuclei, iterative fitting of MQ-MAS spectra by combination of SIMIPSON and MINUIT, simulation of multiple-dimensional PISEMA-type correlation experiments for macroscopically oriented membrane proteins, simulation of Hartman-Hahn polarization transfers in liquid-state NMR, and visualization of the spin evolution under complex composite broad-band excitation pulses. (author)

"McDonald's" reklāmas analīze Latvijā un Maltā - starpkultūru atšķirīgā uztvere

OpenAIRE

Barkēviča, Santa

2016-01-01

Darbā ““McDonald's” reklāmas analīze Latvijā un Maltā – starpkultūru atšķirīgā uztvere” galvenais problēmjautājums, kas jānoskaidro, vai starptautisks uzņēmums var izmantot viena stila reklāmas kampaņu divās dažādās valstīs – Latvijā un Maltā. Galvenais darba mērķis ir noskaidrot, vai starptautisks uzņēmums var veidot vienu reklāmas kampaņu shēmu, un to izmantot dažādās valstīs, kur atrodas tā franšīzes vai filiāles, un kā starpkultūru atšķirība ietekmē reklāmas uztveri. Veicot aptaujas, inte...

“Estado Nación laico y secularización masónica en México”

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Carlos Francisco Martínez Moreno

2011-01-01

Full Text Available Este artículo busca mostrar cómo y porqué los masones practicantes del Rito Nacional Mexicano en el siglo XIX secularizaron su tradición para responder a sus compromisos sociales, patrióticos, liberales y democráticos. Además, muestra cómo ellos sustituyeron La Biblia por la Constitución Política de los Estados Unidos Mexicanos en sus juramentos masónicos, en un contexto social en el que jurarla se consideraba un anatema por el Papa Pío IX y el clero católico, y en un contexto masónico adverso en el que sustituir el Libro de la Ley y participar en la política como masones era contravenir la tradición especulativa londinense.

Quality of Milk Pasteurized Produced By UD. Gading Mas During Storage in Refrigerator

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Manik Eirry Sawitri

2012-02-01

Full Text Available The aim of this research was to study pasteurized milk quality produced by UD. Gading Mas on pH, Acidity, alcohol test and TPC during 5 days storage in refrigerator. On first day showed that  weight mass 1,06 (w/w; fat content 2,00 (g/100g,  protein content 3,02  (g/100g, Zn 1,67 ppm, Cu<0,005 ppm, Pb 0,02 ppm,  As  0,0120 ppm, Hg< 0,0002 ppm, Sn 1,60 ppm dan Cd < 0,001 ppm and organoleptic test included color, flavor and taste were normal. Pasteurized milk characteristic during 5 days refrigeration for pH were 6,57;6,58;6,73;6,60 and 6,50 respectively. Acidity were 1,147 %, 0,145 %, 0,145%, 0,157 %, 0,156 % and 0,175  % respectively. TPC were 6,16 x 101, 1,2. 104; 3,15.104, 0,42.106 and 3,5.108 respectively. It concluded that pasteurized milk produced by UD Gading Mas fulfilled SNI quality standard based on weight mass, pH, acidity, fat, protein, heavy metal content, organoleptic test and TPC.   Keywords: pasteurized milk, quality, refrigerator

Reducing microwave absorption with fast frequency modulation.

Science.gov (United States)

Qin, Juehang; Hubler, A

2017-05-01

We study the response of a two-level quantum system to a chirp signal, using both numerical and analytical methods. The numerical method is based on numerical solutions of the Schrödinger solution of the two-level system, while the analytical method is based on an approximate solution of the same equations. We find that when two-level systems are perturbed by a chirp signal, the peak population of the initially unpopulated state exhibits a high sensitivity to frequency modulation rate. We also find that the aforementioned sensitivity depends on the strength of the forcing, and weaker forcings result in a higher sensitivity, where the frequency modulation rate required to produce the same reduction in peak population would be lower. We discuss potential applications of this result in the field of microwave power transmission, as it shows applying fast frequency modulation to transmitted microwaves used for power transmission could decrease unintended absorption of microwaves by organic tissue.

Role of Mas receptor in renal blood flow response to angiotensin (1-7) in male and female rats.

Science.gov (United States)

Nematbakhsh, Mehdi; Safari, Tahereh

2014-01-01

Epidemiologic and clinical studies have shown that progression of renal disease in male is faster than that in female. However, the exact mechanisms are not well recognized. Angiotensin (1-7) (Ang 1-7) receptor, called "Mas", is an element in the depressor arm of renin angiotensin system (RAS), and its expression is enhanced in females. We test the hypothesis that Mas receptor (MasR) blockade (A779) attenuates renal blood flow (RBF) in response to infusion of graded doses of Ang 1-7 in female rats. Male and female Wistar rats were anesthetized and catheterized. Then, the mean arterial pressure (MAP), RBF, and controlled renal perfusion pressure (RPP) responses to infusion of graded doses of Ang 1-7 (100-1000 ng/kg/min i.v.) with and without A779 were measured in the animals. Basal MAP, RPP, RBF, and renal vascular resistance (RVR) were not significantly different between the two groups. After Ang 1-7 administration, RPP was controlled at a constant level. However, RBF increased in a dose-related manner in response to Ang 1-7 infusion in both male and female rats (Pdoserenal diseases.

Relation Between Acid and Catalytic Properties of Chlorinated Gamma-Alumina. a 31p Mas Nmr and Ftir Investigation

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Guillaume D.

1999-07-01

Full Text Available In this paper, we have studied the effect of chlorine on the surface properties of gamma-alumina, especially on their acid properties. The use of FTIR spectroscopy and 31P MAS NMR of adsorbed trimethylphosphine allows to propose a chlorination mechanism. To correlate the surface properties of these chlorinated gamma-alumina with their catalytic properties, we have used a model reaction, the cracking of n-heptane under reforming conditions. The analysis of the correlation between acid properties determined by 31P MAS NMR and the catalytic results (in terms of activities and selectivities allows to identify which sites are involved in the cracking reaction.

Decision-making support system based on MAS for emergency response to nuclear accidents of marine pressurized-water reactor

International Nuclear Information System (INIS)

Chen Dengke; Zhang Dafa; Jiang Wei; Chen Yonghong

2007-01-01

Emergency decision-making to Marine Pressurized-Water Reactor (MPWR) was severely restricted by the complex environment. To enhance the emergency decision-making ability of MPWR, reducing the effect of emergencies, an emergency Decision-making Support System (DSS) which based on Multi-agent System (MAS) was presented. In the system, the HLA/RTI was used as the support environment, and the structure and the Control Agent (SCA), Analyse Agent (AA), Countermeasure Agent (CA), Evaluation Agent (EVA) and Environment Agent (ENA) were designed. The MAS were with the characteristics of autonomy, reactivity and initiative, which were fully used in the system to make effective decision for emergencies. (authors)

MODIS Airborne Simulator (MAS) Measurements Taken Onboard the NASAER-2 During the TOGA COARE Intensive Observing Period

Data.gov (United States)

National Aeronautics and Space Administration — The TOGA COARE Data Information System has responsibility for distributing information about TOGA COAREdatasets and access paths.The MAS data are available upon...

MAS: Malware Analysis System Based on Hardware-Assisted Virtualization Technology

Science.gov (United States)

Kim, Taehyoung; Kim, Inhyuk; Min, Changwoo; Eom, Young Ik

There are many analysis techniques in order to analyze malicious codes. However, recently malicious codes often evade detection using stealthy obfuscation techniques, and attack computing systems. We propose an enhanced dynamic binary instrumentation using hardware-assisted virtualization technology. As a machine-level analyzer, our system can be isolated from almost the whole threats of malware, and provides single step analysis environment. Proposed system also supports rapid system call analysis environment. We implement our malware analysis system (referred as MAS) on the KVM hypervisor with Intel VT-x virtualization support. Our experiments with benchmarks show that the proposed system provides efficient analysis environment with low overhead.

Estimating local atmosphere-surface fluxes using eddy covariance and numerical Ogive optimization

DEFF Research Database (Denmark)

Sievers, Jakob; Papakyriakou, Tim; Larsen, Søren

2014-01-01

Estimating representative surface-fluxes using eddy covariance leads invariably to questions concerning inclusion or exclusion of low-frequency flux contributions. For studies where fluxes are linked to local physical parameters and up-scaled through numerical modeling efforts, low-frequency cont......Estimating representative surface-fluxes using eddy covariance leads invariably to questions concerning inclusion or exclusion of low-frequency flux contributions. For studies where fluxes are linked to local physical parameters and up-scaled through numerical modeling efforts, low...

A Bio-Economic Case Study of Canadian Honey Bee (Hymenoptera: Apidae) Colonies: Marker-Assisted Selection (MAS) in Queen Breeding Affects Beekeeper Profits

Science.gov (United States)

Baylis, Kathy; Hoover, Shelley E.; Currie, Rob W.; Melathopoulos, Andony P.; Pernal, Stephen F.; Foster, Leonard J.; Guarna, M. Marta

2017-01-01

Abstract Over the past decade in North America and Europe, winter losses of honey bee (Hymenoptera: Apidae) colonies have increased dramatically. Scientific consensus attributes these losses to multifactorial causes including altered parasite and pathogen profiles, lack of proper nutrition due to agricultural monocultures, exposure to pesticides, management, and weather. One method to reduce colony loss and increase productivity is through selective breeding of queens to produce disease-, pathogen-, and mite-resistant stock. Historically, the only method for identifying desirable traits in honey bees to improve breeding was through observation of bee behavior. A team of Canadian scientists have recently identified markers in bee antennae that correspond to behavioral traits in bees and can be tested for in a laboratory. These scientists have demonstrated that this marker-assisted selection (MAS) can be used to produce hygienic, pathogen-resistant honey bee colonies. Based on this research, we present a beekeeping case study where a beekeeper’s profit function is used to evaluate the economic impact of adopting colonies selected for hygienic behavior using MAS into an apiary. Our results show a net profit gain from an MAS colony of between 2% and 5% when Varroa mites are effectively treated. In the case of ineffective treatment, MAS generates a net profit benefit of between 9% and 96% depending on the Varroa load. When a Varroa mite population has developed some treatment resistance, we show that MAS colonies generate a net profit gain of between 8% and 112% depending on the Varroa load and degree of treatment resistance. PMID:28334400

Valsartan attenuates intimal hyperplasia in balloon-injured rat aortic arteries through modulating the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor axis.

Science.gov (United States)

Li, Yonghong; Cai, Shanglang; Wang, Qixin; Zhou, Jingwei; Hou, Bo; Yu, Haichu; Ge, Zhiming; Guan, Renyan; Liu, Xu

2016-05-15

The role of the Mas receptor in the activity of valsartan against intimal hyperplasia is unclear. Herein, we investigated the role of the angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas receptor axis on the activity of valsartan against intimal hyperplasiain balloon-injured rat aortic arteries. Wistar rats were randomized equally into the sham control group, injured group, and injured plus valsartan (20 mg/kg/d)-treated group. Valsartan significantly attenuated the vascular smooth muscle cell proliferation and intimal and medial thickening on days 14 and 28 after injury. The angiotensin-(1-7) levels as well as ACE2 and Mas receptor mRNA/protein expression were significantly decreased in the injured rats, compared to the uninjured rats; meanwhile, the angiotensin II level as well as the ACE and AT1 receptor mRNA/protein expression were increased (all P valsartan significantly increased the angiotensin-(1-7) levels as well as ACE2 and Mas receptor mRNA/protein expression but decreased the angiotensin II level, ACE and AT1 receptor mRNA/protein expression, as well as the p-ERK protein expression, compared to the injured group (all P valsartan attenuates neointimal hyperplasiain balloon-injured rat aortic arteries through activation of the ACE2-angiotensin-(1-7)-Mas axis as well as inhibition of the ACE-angiotensin II-AT1 and p-ERK pathways. Copyright © 2016 Elsevier Inc. All rights reserved.

Reorientation of the Methyl Group in MAs(III) is the Rate-Limiting Step in the ArsM As(III) S-Adenosylmethionine Methyltransferase Reaction.

Science.gov (United States)

Packianathan, Charles; Li, Jiaojiao; Kandavelu, Palani; Sankaran, Banumathi; Rosen, Barry P

2018-03-01

The most common biotransformation of trivalent inorganic arsenic (As(III)) is methylation to mono-, di-, and trimethylated species. Methylation is catalyzed by As(III) S -adenosylmethionine (SAM) methyltransferase (termed ArsM in microbes and AS3MT in animals). Methylarsenite (MAs(III)) is both the product of the first methylation step and the substrate of the second methylation step. When the rate of the overall methylation reaction was determined with As(III) as the substrate, the first methylation step was rapid, whereas the second methylation step was slow. In contrast, when MAs(III) was used as the substrate, the rate of methylation was as fast as the first methylation step when As(III) was used as the substrate. These results indicate that there is a slow conformational change between the first and second methylation steps. The structure of CmArsM from the thermophilic alga Cyanidioschyzon merolae sp. 5508 was determined with bound MAs(III) at 2.27 Å resolution. The methyl group is facing the solvent, as would be expected when MAs(III) is bound as the substrate rather than facing the SAM-binding site, as would be expected for MAs(III) as a product. We propose that the rate-limiting step in arsenic methylation is slow reorientation of the methyl group from the SAM-binding site to the solvent, which is linked to the conformation of the side chain of a conserved residue Tyr70.

Considerations for Consortia as States Transition Away from AA-MAS. NCEO Brief. Number 7

Science.gov (United States)

National Center on Educational Outcomes, 2014

2014-01-01

States with an alternate assessment based on modified achievement standards (AA-MAS) that received a flexibility waiver from some of the requirements of No Child Left Behind are required to phase out their use of this assessment. And, on August 23, 2013, the U.S. Department of Education published a proposed rollback of regulation that allowed the…

Mas Gusó: a Roman military Settlement in the suburbium of Emporiae

Directory of Open Access Journals (Sweden)

Josep Casas Genover

2016-11-01

Full Text Available Although the site of Mas Gusó (province of Girona has been interpreted as a Roman uilla, this is actually a public building. Its existence have to be contextualized within the frame of the structures established by the Roman authority for territorial control closely linked to the creation of a new road network and a tax collection system. We also analyse its survival until the 3rd century AD, which are closely related to the nearby city of Emporiae.

A Bio-Economic Case Study of Canadian Honey Bee (Hymenoptera: Apidae) Colonies: Marker-Assisted Selection (MAS) in Queen Breeding Affects Beekeeper Profits.

Science.gov (United States)

Bixby, Miriam; Baylis, Kathy; Hoover, Shelley E; Currie, Rob W; Melathopoulos, Andony P; Pernal, Stephen F; Foster, Leonard J; Guarna, M Marta

2017-06-01

Over the past decade in North America and Europe, winter losses of honey bee (Hymenoptera: Apidae) colonies have increased dramatically. Scientific consensus attributes these losses to multifactorial causes including altered parasite and pathogen profiles, lack of proper nutrition due to agricultural monocultures, exposure to pesticides, management, and weather. One method to reduce colony loss and increase productivity is through selective breeding of queens to produce disease-, pathogen-, and mite-resistant stock. Historically, the only method for identifying desirable traits in honey bees to improve breeding was through observation of bee behavior. A team of Canadian scientists have recently identified markers in bee antennae that correspond to behavioral traits in bees and can be tested for in a laboratory. These scientists have demonstrated that this marker-assisted selection (MAS) can be used to produce hygienic, pathogen-resistant honey bee colonies. Based on this research, we present a beekeeping case study where a beekeeper's profit function is used to evaluate the economic impact of adopting colonies selected for hygienic behavior using MAS into an apiary. Our results show a net profit gain from an MAS colony of between 2% and 5% when Varroa mites are effectively treated. In the case of ineffective treatment, MAS generates a net profit benefit of between 9% and 96% depending on the Varroa load. When a Varroa mite population has developed some treatment resistance, we show that MAS colonies generate a net profit gain of between 8% and 112% depending on the Varroa load and degree of treatment resistance. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Two-Stage MAS Technique for Analysis of DRA Elements and Arrays on Finite Ground Planes

DEFF Research Database (Denmark)

Larsen, Niels Vesterdal; Breinbjerg, Olav

2007-01-01

A two-stage Method of Auxiliary Sources (MAS) technique is proposed for analysis of dielectric resonator antenna (DRA) elements and arrays on finite ground planes (FGPs). The problem is solved by first analysing the DRA on an infinite ground plane (IGP) and then using this solution to model the FGP...

Frequency and persistency of DNA vaccine encoding GP25 by oral on common carp

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Sri Nuryati

2015-05-01

Full Text Available ABSTRACT Koi herpesvirus (KHV is a major viral pathogen that infects common carp and koi. KHV disease outbreak is happened in almost all centre of common carp culture in Indonesia and caused mass mortality. Deoxyribonucleic acid (DNA vaccination method is one of ways to cope with KHV infection. Vaccines were commonly given by injection. The aim of this research was to get frequency and persistency of DNA vaccine encoding GP25 given by oral delivery method in common carp. This research would like to determine dose, frequency of vaccination, persistency of DNA vaccine and culture medium for the bacterial host. DNA vaccine persistency test was done by using polymerase chain reaction (PCR method with the specific primer for GP25 gene. The results showed that level of DNA vaccine that could be detected in feed was 7.56 ng (equal to 1.598×1010 copies. Efficient culture medium for Escherichia coli DH5α carrying DNA vaccine was LB triptone. Feeding fish with diet supplemented with 1 mL E. coli DH5α containing DNA vaccine for each fish and two times a week allowed persistence of DNA vaccine in kindney and spleen. Keywords: common carp, KHV, DNA vaccine, GP25, persistance  ABSTRAK Koi herpesvirus (KHV adalah virus patogen utama yang menginfeksi ikan mas dan ikan koi. Wabah penyakit KHV terjadi di hampir semua sentra budidaya ikan mas di Indonesia dan menyebabkan kematian massal ikan. Metode vaksinasi DNA merupakan salah satu cara yang dapat dilakukan untuk menanggulangi serangan KHV. Pemberian vaksin umumnya dilakukan dengan cara injeksi. Tujuan penelitian ini adalah untuk menguji frekuensi dan persistensi vaksin DNA GP25 antivirus KHV yang diberikan melalui oral pada ikan mas. Pada penelitian ini dilakukan uji dosis, frekuensi pemberian vaksin, persistensi vaksin DNA, dan media kultur bakteri inang. Persistensi vaksin DNA dianalisis menggunakan metode PCR dengan primer spesifik gen GP25. Hasil penelitian menunjukkan bahwa dosis vaksin DNA yang

Experimental and Numerical analysis of Metallic Bellow for Acoustic Performance

Science.gov (United States)

Panchwadkar, Amit A.; Awasare, Pradeep J., Dr.; Ingle, Ravidra B., Dr.

2017-08-01

Noise will concern about the work environment of industry. Machinery environment has overall noise which interrupts communication between the workers. This problem of miscommunication and health hazard will make sense to go for noise attenuation. Modification in machine setup may affect the performance of it. Instead of that, Helmholtz resonator principle will be a better option for noise reduction along the transmission path. Resonator has design variables which gives resonating frequency will help us to confirm the frequency range. This paper deals with metallic bellow which behaves like inertial mass under incident sound wave. Sound wave energy is affected by hard boundary condition of resonator and bellow. Metallic bellow is used in combination with resonator to find out Transmission loss (TL). Microphone attachment with FFT analyzer will give the frequency range for numerical analysis. Numerical analysis of bellow and resonator is carried out to summarize the acoustic behavior of bellow. Bellow can be numerically analyzed to check noise attenuation for centrifugal blower. An impedance tube measurement technique is performed to validate the numerical results for assembly. Dimensional and shape modification can be done to get the acoustic performance of bellow.

Numerically controlled oscillator for the Fermilab Booster

International Nuclear Information System (INIS)

Crisp, J.L.; Ducar, R.J.

1989-01-01

In order to improve the stability of the Fermilab Booster low level rf system, a numerically controlled oscillator system is being constructed. Although the system has not been implemented to date, the design is outlined in this paper. The heart of the new system consists of a numerically synthesized frequency generator manufactured by the Sciteq Company. The 3 GHz/sec rate and 30 to 53 MHz range of the Booster frequency program required the design of a CAMAC based, fast-cycling (1 MHz), 65K x 32 bit, digital function generator. A 1 MHz digital adder and 12 bit analog to digital converter will be used to correct small program errors by phase locking the oscillator to the beam. 6 refs., 1 fig

Successfully Transitioning from the AA-MAS to the General Assessment. NCEO Policy Directions. Number 22

Science.gov (United States)

Lazarus, Sheryl; Thurlow, Martha; Christensen, Laurene; Shyyan, Vitaliy

2014-01-01

Federal policy initiatives such as the flexibility waivers for accountability are requiring that states transition away from the use of an alternate assessment based on modified achievement standards (AA-MAS). It is expected that those students who had participated in that assessment will instead participate in the state's general assessment (or a…

Broadband frequency and angular response of a sinusoidal bull’s eye antenna

Science.gov (United States)

Beaskoetxea, U.; Navarro-Cía, M.; Beruete, M.

2016-07-01

A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of these antennas as frequency is varied is experimentally demonstrated and corroborated through theoretical and numerical results. From the experimental results the dispersion diagram of the n  =  -1 and n  =  -2 space harmonics is extracted, and the operation at different frequency regimes is identified and discussed. In order to show the contribution of each half of the antenna, numerical examples of the near-field behavior are also displayed. Overall, experimental results are in good qualitative and quantitative agreement with theoretical and numerical calculations. Finally, an analysis of the beamwidth as a function of frequency is performed, showing that it can achieve values below 1.5° in a fractional bandwidth of 4% around the operation frequency, which is an interesting frequency-stable broadside radiation.

Role of Mas Receptor Antagonist A799 in Renal Blood Flow Response to Ang 1-7 after Bradykinin Administration in Ovariectomized Estradiol-Treated Rats

Directory of Open Access Journals (Sweden)

Aghdas Dehghani

2015-01-01

Full Text Available Background. The accompanied role of Mas receptor (MasR, bradykinin (BK, and female sex hormone on renal blood flow (RBF response to angiotensin 1-7 is not well defined. We investigated the role of MasR antagonist (A779 and BK on RBF response to Ang 1-7 infusion in ovariectomized estradiol-treated rats. Methods. Ovariectomized Wistar rats received estradiol (OVE or vehicle (OV for two weeks. Catheterized animals were subjected to BK and A799 infusion and mean arterial pressure (MAP, RBF, and renal vascular resistance (RVR responses to Ang 1-7 (0, 100, and 300 ng kg−1 min−1 were determined. Results. Percentage change of RBF (%RBF in response to Ang1-7 infusion increased in a dose-dependent manner. In the presence of BK, when MasR was not blocked, %RBF response to Ang 1-7 in OVE group was greater than OV group significantly (P<0.05. Infusion of 300 ng kg−1 min−1 Ang 1-7 increased RBF by 6.9±1.9% in OVE group versus 0.9±1.8% in OV group. However when MasR was blocked, %RBF response to Ang 1-7 in OV group was greater than OVE group insignificantly. Conclusion. Coadministration of BK and A779 compared to BK alone increased RBF response to Ang 1-7 in vehicle treated rats. Such observation was not seen in estradiol treated rats.

13C and 15N CP/MAS, 1H-15N SCT CP/MAS and FTIR spectroscopy as tools for qualitative detection of the presence of zwitterionic and non-ionic forms of ansa-macrolide 3-formylrifamycin SV and its derivatives in solid state.

Science.gov (United States)

Przybylski, Piotr; Pyta, Krystian; Klich, Katarzyna; Schilf, Wojciech; Kamieński, Bohdan

2014-01-01

(13)C, (15)N CP/MAS, including (1)H-(13)C and (1)H-(15)N short contact time CP/MAS experiments, and FTIR methods were applied for detailed structural characterization of ansa-macrolides as 3-formylrifamycin SV (1) and its derivatives (2-6) in crystal and in powder forms. Although HPLC chromatograms for 2/CH3 OH and 2/CH3 CCl3 were the same for rifampicin crystals dissolved in respective solvents, the UV-vis data recorded for them were different in 300-375 nm region. Detailed solid state (13)C and (15)N CP/MAS NMR and FTIR studies revealed that rifampicin (2), in contrast to 3-formylrifamycin SV (1) and its amino derivatives (3-6), can occur in pure non-ionic or zwitterionic forms in crystal and in pure these forms or a mixture of them in a powder. Multinuclear CP/MAS and FTIR studies demonstrated also that 3-6 derivatives were present exclusively in pure zwitterionic forms, both in powder and in crystal. On the basis of the solid state NMR and FTIR studies, two conformers of 3-formylrifamycin SV were detected in powder form due to the different orientations of carbonyl group of amide moiety. The PM6 molecular modeling at the semi-empirical level of theory, allowed visualization the most energetically favorable non-ionic and zwitterionic forms of 1-6 antibiotics, strongly stabilized via intramolecular H-bonds. FTIR studies indicated that the originally adopted forms of these type antibiotics in crystal or in powder are stable in standard laboratory conditions in time. The results presented point to the fact that because of a possible presence of two forms of rifampicin (compound 2), quantification of the content of this antibiotic in relevant pharmaceuticals needs caution. Copyright © 2013 John Wiley & Sons, Ltd.

ANALISIS PERHITUNGAN DAN PELAPORAN PAJAK PERTAMBAHAN NILAI PADA PT FAJAR MAS KARYATAMA

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MARINDO PUTRA

2017-05-01

Full Text Available Value Added Tax (VAT is Tax that imposed on any apreciation in value of the goods or services in its circulation from producers to consumers. Through the calculation dan reporting is good, then the company may be said it has complied with the applicable rules in order to enhance the national development budget of the Government. PT Fajar Mas Karyatama as a company engaged intrade of goods subject to VAT, as in general make a purchase with Input Tax which may be credited. The purpose of this study to know whether the application of VAT and VAT underpayment or overpayment in accordance with law of VAT No. 42 of 2009. This study used a comparative method. The company will account for and report the delivery of Added Value Tax in the Notice Period of Added Value Tax (VAT Period SPT. VAT calculations made by company are the basis for the report required to implement Tax Laws for the companies. Conclusion is that application of VAT in the calculating and reporting of PT Fajar Mas Karyatama was almost accordance with the VAT Act applied and through the application of VAT, namely the purchase and sale of Taxable Goods so that the sum of the difference by the number of Input Tax or Output Tax generate VAT Less/More Pay at the end each mont, it is accordance with the Law of VAT No. 42 of 2009.

Quality of Kelantan drinking water and knowledge, attitude and practice among the population of Pasir Mas, Malaysia.

Science.gov (United States)

Ab Razak, N H; Praveena, S M; Aris, A Z; Hashim, Z

2016-02-01

Information about the quality of drinking water, together with analysis of knowledge, attitude and practice (KAP) analysis and health risk assessment (HRA) remain limited. The aims of this study were: (1) to ascertain the level of KAP regarding heavy metal contamination of drinking water in Pasir Mas; (2) to determine the concentration of heavy metals (Al, Cr, Cu, Fe, Ni, Pb, Zn and Cd) in drinking water in Pasir Mas; and (3) to estimate the health risks (non-carcinogenic and carcinogenic) caused by heavy metal exposure through drinking water using hazard quotient and lifetime cancer risk. Information on KAP was collected using a standardized questionnaire. Heavy metal analysis of drinking water samples was performed using graphite furnace atomic absorption spectrophotometry. The population of Pasir Mas has good knowledge (80%), a less positive attitude (93%) and good practice (81%) towards heavy metal contamination of drinking water. The concentrations of heavy metals analysed in this study were found to be below the permissible limits for drinking water set by the Malaysian Ministry of Health and the World Health Organization. The HRA showed no potential non-carcinogenic and carcinogenic risks from the intake of heavy metal through drinking water. By investigating the quality of drinking water, KAP and HRA, the results of this study will provide authorities with the knowledge and resources to improve the management of drinking water quality in the future. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Who Are the Students Who May Qualify for an Alternate Assessment Based on Modified Academic Achievement Standards (AA-MAS)?: Focus Group Results. Synthesis Report 79

Science.gov (United States)

Berndt, Sandra; Ebben, Barbara; Kubinski, Eva; Sim, Grant; Liu, Kristin; Lazarus, Sheryl; Thurlow, Martha; Christian, Elizabeth

2011-01-01

Beginning in 2007, federal regulations to two major education laws gave state departments of education the option to develop an alternate assessment based on modified achievement standards (AA-MAS) for some students with disabilities. The regulations stated that the AA-MAS was intended for students who were being instructed in the grade-level…

Space-resolved characterization of high frequency atmospheric-pressure plasma in nitrogen, applying optical emission spectroscopy and numerical simulation

International Nuclear Information System (INIS)

Rajasekaran, Priyadarshini; Ruhrmann, Cornelia; Bibinov, Nikita; Awakowicz, Peter

2011-01-01

Averaged plasma parameters such as electron distribution function and electron density are determined by characterization of high frequency (2.4 GHz) nitrogen plasma using both experimental methods, namely optical emission spectroscopy (OES) and microphotography, and numerical simulation. Both direct and step-wise electron-impact excitation of nitrogen emissions are considered. The determination of space-resolved electron distribution function, electron density, rate constant for electron-impact dissociation of nitrogen molecule and the production of nitrogen atoms, applying the same methods, is discussed. Spatial distribution of intensities of neutral nitrogen molecule and nitrogen molecular ion from the microplasma is imaged by a CCD camera. The CCD images are calibrated using the corresponding emissions measured by absolutely calibrated OES, and are then subjected to inverse Abel transformation to determine space-resolved intensities and other parameters. The space-resolved parameters are compared, respectively, with the averaged parameters, and an agreement between them is established. (paper)

Experimental article – Reducing effective dose to a paediatric phantom by using different combinations of kVp, mAs and additional filtration whilst maintaining image quality

NARCIS (Netherlands)

Elsbeth Huizinga; Ana Pereira; Wouter Schaake; Charlotte Bloomfield; Heidi Knight; Emilie Crausaz; Hanne Hustveit; Ruurd Visser; Vanja Harsaker; Diane Chabloz; Filipa Boavida

2015-01-01

Purpose: To determine whether using different combinations of kVp and mAs with additional filtration can reduce the effective dose to a paediatric phantom whilst maintaining diagnostic image quality. Methods: 27 images of a paediatric AP pelvis phantom were acquired with different kVp, mAs

Improvement of frequency variability of the folded-coaxial radio-frequency quadrupole linac by installing a detachable stem in its resonator

International Nuclear Information System (INIS)

Kamigaito, Osamu; Goto, Akira; Miyazawa, Yoshitoshi; Chiba, Toshiya; Hemmi, Masatake; Kase, Masayuki; Kohara, Shigeo; Yano, Yasushige

1995-01-01

The beneficial effect of adding a detachable stem to the folded-coaxial resonator of the frequency-variable radio-frequency quadrupole (RFQ) linac previously reported was examined experimentally using a half-scale model as well as by numerical analyses. As a result, this simple modification was found to extend variable frequencies to a high region without increase of rf power consumption. (author)

Inverse scattering problems with multi-frequencies

International Nuclear Information System (INIS)

Bao, Gang; Li, Peijun; Lin, Junshan; Triki, Faouzi

2015-01-01

This paper is concerned with computational approaches and mathematical analysis for solving inverse scattering problems in the frequency domain. The problems arise in a diverse set of scientific areas with significant industrial, medical, and military applications. In addition to nonlinearity, there are two common difficulties associated with the inverse problems: ill-posedness and limited resolution (diffraction limit). Due to the diffraction limit, for a given frequency, only a low spatial frequency part of the desired parameter can be observed from measurements in the far field. The main idea developed here is that if the reconstruction is restricted to only the observable part, then the inversion will become stable. The challenging task is how to design stable numerical methods for solving these inverse scattering problems inspired by the diffraction limit. Recently, novel recursive linearization based algorithms have been presented in an attempt to answer the above question. These methods require multi-frequency scattering data and proceed via a continuation procedure with respect to the frequency from low to high. The objective of this paper is to give a brief review of these methods, their error estimates, and the related mathematical analysis. More attention is paid to the inverse medium and inverse source problems. Numerical experiments are included to illustrate the effectiveness of these methods. (topical review)

Experimental article – Reducing effective dose to a paediatric phantom by using different combinations of kVp, mAs and additional filtration whilst maintaining image quality

NARCIS (Netherlands)

Huizinga, Elsbeth; Schaake, Wouter; Visser, Ruurd; Bloomfield, Charlotte; Boavida, Filipa; Chabloz, Diane; Crausaz, Emilie; Hustveit, Hanne; Knight, Heidi; Pereira, Anna; Harsaker, Vanja

2015-01-01

Purpose: To determine whether using different combinations of kVp and mAs with additional filtration can reduce the effective dose to a paediatric phantom whilst maintaining diagnostic image quality. Methods: 27 images of a paediatric AP pelvis phantom were acquired with different kVp, mAs and

Sine-squared shifted pulses for recoupling interactions in solid-state NMR

Science.gov (United States)

Jain, Mukul G.; Rajalakshmi, G.; Equbal, Asif; Mote, Kaustubh R.; Agarwal, Vipin; Madhu, P. K.

2017-06-01

Rotational-Echo DOuble-Resonance (REDOR) is a versatile experiment for measuring internuclear distance between two heteronuclear spins in solid-state NMR. At slow to intermediate magic-angle spinning (MAS) frequencies, the measurement of distances between strongly coupled spins is challenging due to rapid dephasing of magnetisation. This problem can be remedied by employing the pulse-shifted version of REDOR known as Shifted-REDOR (S-REDOR) that scales down the recoupled dipolar coupling. In this study, we propose a new variant of the REDOR sequence where the positions of the π pulses are determined by a sine-squared function. This new variant has scaling properties similar to S-REDOR. We use theory, numerical simulations, and experiments to compare the dipolar recoupling efficiencies and the experimental robustness of the three REDOR schemes. The proposed variant has advantages in terms of radiofrequency field requirements at fast MAS frequencies.

Interneta sociālie tīkli draugiem.lv, mammam/tetiem.lv un twitter.com kā reklāmas nesēji Latvijā (2009.gads)

OpenAIRE

Vismane, Inese

2010-01-01

Maģistra darba tēma ir „Interneta sociālie tīkli draugiem.lv, mammam/tetiem.lv un twitter.com kā reklāmas nesēji Latvijā (2009.gads)”. Darba mērķis ir izpētīt Latvijas interneta sociālo tīklu vidi kā potenciāli augošu un reklāmai piemērotu, kā arī izpētīt pamanāmākos reklāmas gadījumus šajos portālos. Teorijas daļā tiek apskatīta Web 2.0 ēra, interneta reklāmas un sociālo mediju mārketinga īpatnības, sociālo tīklu fenomens un teorijas, Latvijas reklāmas tirgus un auditorija, kā arī sociāl...

Pre- And Post-Enron Learnings On Learning In M&A Environments - A Qualitative Study In Preparation Of A Dissertation On The Influence Of Management Andragogy On Executives Ability To Successfully Manage M&As

OpenAIRE

Jacqueline Fendt

2011-01-01

In a global economy characterized by convergence and consolidation, by shareholder pressure, by the war for talent, for knowledge and for customer bondage, Merger and Acquisition transactions (M&As) are seen as a fast, efficient and spectacular way to innovate. M&As are therefore a frequently used strategic tool for corporate development. However, as of now, more than 75% of all M&As fail to meet objectives and 50% even destroy shareholder value. M&As often fail due to poor leadership. Th...

Feminism and Postmodernism in Paloma Díaz-Mas's "The World According to Valdés" and "In Search of a Portrait"

Directory of Open Access Journals (Sweden)

Fuencisla Zomeño

2002-06-01

Full Text Available This paper analyzes the influence of postmodernism in Paloma Díaz-Mas's feminist approach through two short stories, "The World According to Valdés," and "In Search of a Portrait." The political situation after Franco's death embraced democracy which allowed writers to pay more attention to intellectual concerns. Women writers steered the radical positions of the 1970s toward a more philosophical and intellectual analysis of reality and artistic expression during the eighties. In these two short stories, Díaz-Mas addresses women's issues by questioning the scope of modernist and humanist views. She criticizes the modernist concept of unity (text/identity pointing out the discrimination that this unity creates in art, through the distinction between high art/mass culture; and in the individual, through the distinction between feminine/masculine and high/low. Even though Díaz-Mas's main characters in the two stories are women, she does not solely focus on defending them, but she contrasts present and past to parody the causes which produce discrimination in the social and artistic processes.

Broadband frequency and angular response of a sinusoidal bull’s eye antenna

International Nuclear Information System (INIS)

Beaskoetxea, U; Beruete, M; Navarro-Cía, M

2016-01-01

A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of these antennas as frequency is varied is experimentally demonstrated and corroborated through theoretical and numerical results. From the experimental results the dispersion diagram of the n   =  −1 and n   =  −2 space harmonics is extracted, and the operation at different frequency regimes is identified and discussed. In order to show the contribution of each half of the antenna, numerical examples of the near-field behavior are also displayed. Overall, experimental results are in good qualitative and quantitative agreement with theoretical and numerical calculations. Finally, an analysis of the beamwidth as a function of frequency is performed, showing that it can achieve values below 1.5° in a fractional bandwidth of 4% around the operation frequency, which is an interesting frequency-stable broadside radiation. (paper)

47 CFR 73.603 - Numerical designation of television channels.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Numerical designation of television channels... SERVICES RADIO BROADCAST SERVICES Television Broadcast Stations § 73.603 Numerical designation of television channels. (a) Channel No. Frequency band (MHz) 2 54-60 3 60-66 4 66-72 5 76-82 6 82-88 7 174-180 8...

On the frequency scalings of RF guns

International Nuclear Information System (INIS)

Lin, L.C.; Chen, S.C.; Wurtele, J.S.

1995-01-01

A frequency scaling law for RF guns is derived from the normalized Vlasov-Maxwell equations. It shows that higher frequency RF guns can generate higher brightness beams under the assumption that the accelerating gradient and all beam and structure parameters are scaled with the RF frequency. Numerical simulation results using MAGIC confirm the scaling law. A discussion of the range of applicability of the law is presented. copyright 1995 American Institute of Physics

MODELAGEM DE UM SISTEMA MULTIAGENTE DE APOIO À PBL UTILIZANDO A METODOLOGIA MAS-COMMONKADS+

Directory of Open Access Journals (Sweden)

Laysa Mabel de Oliveira Fontes

2014-10-01

Full Text Available A aprendizagem baseada em problema (Problem-Based Learning - PBL é um método no qual os estudantes aprendem através da resolução de um problema que, em geral, não possui uma solução trivial e uma única solução correta. A PBL destaca o trabalho em equipe como um dos principais requisitos para o sucesso do processo de aprendizagem, ou seja, a colaboração é essencial. No entanto, a implantação de um método de ensino com base na PBL não é uma tarefa trivial. Em Ambientes Virtuais de Aprendizagem (AVAs, a complexidade de implantação deste método é ainda maior, pois o facilitador nem sempre pode detectar possíveis problemas na colaboração, nem possui todas as informações necessárias para aplicar as técnicas de aprendizagem deste método. Desta forma, este artigo apresenta o processo de modelagem de um Sistema Multiagente (SMA de apoio à PBL. O SMA proposto foi modelado utilizando a metodologia MAS-CommonKADS+, que consiste em uma extensão da metodologia MAS-CommonKADS.

Numerical processing of ultrasonic holographic data

International Nuclear Information System (INIS)

Langenberg, K.J.; Kiefer, R.; Wosnitza, M.; Schmitz, V.; Fraunhofer-Gesellschaft zur Foerderung der Angewandten Forschung e.V., Saarbruecken

1980-01-01

Reconstructing ultrasonic holographic data numerically, the well-known Fresnel approximation is a first step in evaluating the Rayleigh-Sommerfeld diffraction formula, that is to say, a one- or two-dimensional Fourier-transform of the holographic data multiplied by a complex phase factor has to be computed. The present contribution investigates the relation between flaw depth and aperture size yielding the more advantageous use of the spatial frequency approach where the advantage is in terms of the number of samples and hence computation time in evaluating Fourier transforms numerically. (orig.) [de

Fast focus estimation using frequency analysis in digital holography.

Science.gov (United States)

Oh, Seungtaik; Hwang, Chi-Young; Jeong, Il Kwon; Lee, Sung-Keun; Park, Jae-Hyeung

2014-11-17

A novel fast frequency-based method to estimate the focus distance of digital hologram for a single object is proposed. The focus distance is computed by analyzing the distribution of intersections of smoothed-rays. The smoothed-rays are determined by the directions of energy flow which are computed from local spatial frequency spectrum based on the windowed Fourier transform. So our method uses only the intrinsic frequency information of the optical field on the hologram and therefore does not require any sequential numerical reconstructions and focus detection techniques of conventional photography, both of which are the essential parts in previous methods. To show the effectiveness of our method, numerical results and analysis are presented as well.

Gaming frequency and academic performance

OpenAIRE

Ip, Barry; Jacobs, Gabriel; Watkins, Alan

2008-01-01

There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency –measured as the amount of time undergraduate students spend playing games in their free time – and their academic performance as measured by their examination marks. U...

Numerical simulations of time-resolved quantum electronics

International Nuclear Information System (INIS)

Gaury, Benoit; Weston, Joseph; Santin, Matthieu; Houzet, Manuel; Groth, Christoph; Waintal, Xavier

2014-01-01

Numerical simulation has become a major tool in quantum electronics both for fundamental and applied purposes. While for a long time those simulations focused on stationary properties (e.g. DC currents), the recent experimental trend toward GHz frequencies and beyond has triggered a new interest for handling time-dependent perturbations. As the experimental frequencies get higher, it becomes possible to conceive experiments which are both time-resolved and fast enough to probe the internal quantum dynamics of the system. This paper discusses the technical aspects–mathematical and numerical–associated with the numerical simulations of such a setup in the time domain (i.e. beyond the single-frequency AC limit). After a short review of the state of the art, we develop a theoretical framework for the calculation of time-resolved observables in a general multiterminal system subject to an arbitrary time-dependent perturbation (oscillating electrostatic gates, voltage pulses, time-varying magnetic fields, etc.) The approach is mathematically equivalent to (i) the time-dependent scattering formalism, (ii) the time-resolved non-equilibrium Green’s function (NEGF) formalism and (iii) the partition-free approach. The central object of our theory is a wave function that obeys a simple Schrödinger equation with an additional source term that accounts for the electrons injected from the electrodes. The time-resolved observables (current, density, etc.) and the (inelastic) scattering matrix are simply expressed in terms of this wave function. We use our approach to develop a numerical technique for simulating time-resolved quantum transport. We find that the use of this wave function is advantageous for numerical simulations resulting in a speed up of many orders of magnitude with respect to the direct integration of NEGF equations. Our technique allows one to simulate realistic situations beyond simple models, a subject that was until now beyond the simulation

Cross-polarization phenomena in the NMR of fast spinning solids subject to adiabatic sweeps

Energy Technology Data Exchange (ETDEWEB)

Wi, Sungsool, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il; Gan, Zhehong [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Schurko, Robert [Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor N9B 3P4, Ontario (Canada); Frydman, Lucio, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Department of Chemical Physics, Weizmann Institute of Sciences, 76100 Rehovot (Israel)

2015-02-14

Cross-polarization magic-angle spinning (CPMAS) experiments employing frequency-swept pulses are explored within the context of obtaining broadband signal enhancements for rare spin S = 1/2 nuclei at very high magnetic fields. These experiments employ adiabatic inversion pulses on the S-channel ({sup 13}C) to cover a wide frequency offset range, while simultaneously applying conventional spin-locking pulse on the I-channel ({sup 1}H). Conditions are explored where the adiabatic frequency sweep width, Δν, is changed from selectively irradiating a single magic-angle-spinning (MAS) spinning centerband or sideband, to sweeping over multiple sidebands. A number of new physical features emerge upon assessing the swept-CP method under these conditions, including multiple zero- and double-quantum CP transfers happening in unison with MAS-driven rotary resonance phenomena. These were examined using an average Hamiltonian theory specifically designed to tackle these experiments, with extensive numerical simulations, and with experiments on model compounds. Ultrawide CP profiles spanning frequency ranges of nearly 6⋅γB{sub 1}{sup s} were predicted and observed utilizing this new approach. Potential extensions and applications of this extremely broadband transfer conditions are briefly discussed.

1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

Directory of Open Access Journals (Sweden)

Carmelo Corsaro

2015-01-01

Full Text Available NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication.

Synchronization of vortex formation frequency with the body motion frequency at high Reynolds numbers

Energy Technology Data Exchange (ETDEWEB)

Pereira, Luiz Antonio Alcantara [Federal University of Itajuba (UNIFEI), MG (Brazil). Inst. of Mechanical Engineering], E-mail: luizantp@unifei.edu.br; Hirata, Miguel Hiroo [State University of Rio de Janeiro (FAT/UERJ), Resende, RJ (Brazil). Fac. de Tecnologia], E-mail: hirata@fat.uerj.br

2010-07-01

Understanding vortex induced vibrations is of great importance in the design of a variety of offshore engineering structures, nuclear plant components and cylindrical elements in tube-bank heat exchangers, for example. If a body is placed in a flow, it experiences alternating lift and drag forces caused by the asymmetric formation of vortices, which can cause a structure to vibrate. One of the most interesting features of this flow is the phenomenon of lock-in which is observed when the vortex shedding frequency is close to the body oscillation frequency. This paper presents the results of numerical experiments on vortex shedding from a circular cylinder vibrating in-line or transversely with an incident uniform flow at Reynolds number of 1.0 x 10{sup 5}. The frequencies of the lift and drag coefficients are compared with the body motion frequency when the frequency ratio is about unity. (author)

A new aluminium-hydrate species in hydrated Portland cements characterized by 27Al and 29Si MAS NMR spectroscopy

International Nuclear Information System (INIS)

Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Jorgen

2006-01-01

Recent 27 Al MAS NMR studies of hydrated Portland cements and calcium-silicate-hydrate (C-S-H) phases have shown a resonance from Al in octahedral coordination, which cannot be assigned to the well-known aluminate species in hydrated Portland cements. This resonance, which exhibits the isotropic chemical shift δ iso = 5.0 ppm and the quadrupole product parameter P Q = 1.2 MHz, has been characterized in detail by 27 Al MAS and 27 Al{ 1 H} CP/MAS NMR for different hydrated white Portland cements and C-S-H phases. These experiments demonstrate that the resonance originates from an amorphous or disordered aluminate hydrate which contains Al(OH) 6 3- or O x Al(OH) 6-x (3+x)- units. The formation of the new aluminate hydrate is related to the formation of C-S-H at ambient temperatures, however, it decomposes by thermal treatment at temperatures of 70-90 o C. From the experiments in this work it is proposed that the new aluminate hydrate is either an amorphous/disordered aluminate hydroxide or a calcium aluminate hydrate, produced as a separate phase or as a nanostructured surface precipitate on the C-S-H phase. Finally, the possibilities of Al 3+ for Ca 2+ substitution in the principal layers and interlayers of the C-S-H structure are discussed

Badania jakości regeneratu ze zużytych mas ze spoiwem organicznym

Directory of Open Access Journals (Sweden)

R. Dańko

2012-12-01

Full Text Available W publikacji przedstawiono uzupełniające metody badań oraz aparaturę do oceny jakości regeneratu i tych właściwości masformierskich ze spoiwami utwardzanymi chemicznie, przygotowywanych z regeneratem, które są istotne dla kompleksowej oceny procesurecyklingu osnowy. Nowoczesne systemy oceny mas formierskich wymagają bardziej wnikliwego podejścia do czynników decydującychzarówno o ich przydatności technologicznej jak również o wpływie na otaczające środowisko naturalne. W tym kontekście pełna ocenajakości zregenerowanej osnowy wykracza poza zwyczajowo stosowane metody instrumentalne i wymaga ich uzupełnienia o bardziejzaawansowane aparaturowo metody badawcze. Pozwala to szerzej spojrzeć na ocenę zregenerowanej osnowy, zarówno w aspekcie jejużycia do sporządzania mas formierskich, jako substytutu świeżego piasku, ale także pod kątem ochrony środowiska. Do takichnowoczesnych metod można zaliczyć między innymi analizę ziarnową regeneratu za pomocą dyfrakcji laserowej, a także ocenęgazotwórczości masy formierskiej oraz identyfikację rodzaju emitowanych gazów i zawartości w nich gazów z grupy BTEX, które sąszczególnie niebezpieczne z punktu widzenia BHP.

Lipid bilayer-bound conformation of an integral membrane beta barrel protein by multidimensional MAS NMR

International Nuclear Information System (INIS)

Eddy, Matthew T.; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G.

2015-01-01

The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms two-dimensional lipid crystals, showing remarkable spectral resolution (0.5–0.3 ppm for 13 C line widths and <0.5 ppm 15 N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

Measuring multi-joint stiffness during single movements: numerical validation of a novel time-frequency approach.

Science.gov (United States)

Piovesan, Davide; Pierobon, Alberto; DiZio, Paul; Lackner, James R

2012-01-01

This study presents and validates a Time-Frequency technique for measuring 2-dimensional multijoint arm stiffness throughout a single planar movement as well as during static posture. It is proposed as an alternative to current regressive methods which require numerous repetitions to obtain average stiffness on a small segment of the hand trajectory. The method is based on the analysis of the reassigned spectrogram of the arm's response to impulsive perturbations and can estimate arm stiffness on a trial-by-trial basis. Analytic and empirical methods are first derived and tested through modal analysis on synthetic data. The technique's accuracy and robustness are assessed by modeling the estimation of stiffness time profiles changing at different rates and affected by different noise levels. Our method obtains results comparable with two well-known regressive techniques. We also test how the technique can identify the viscoelastic component of non-linear and higher than second order systems with a non-parametrical approach. The technique proposed here is very impervious to noise and can be used easily for both postural and movement tasks. Estimations of stiffness profiles are possible with only one perturbation, making our method a useful tool for estimating limb stiffness during motor learning and adaptation tasks, and for understanding the modulation of stiffness in individuals with neurodegenerative diseases.

Measuring multi-joint stiffness during single movements: numerical validation of a novel time-frequency approach.

Directory of Open Access Journals (Sweden)

Davide Piovesan

Full Text Available This study presents and validates a Time-Frequency technique for measuring 2-dimensional multijoint arm stiffness throughout a single planar movement as well as during static posture. It is proposed as an alternative to current regressive methods which require numerous repetitions to obtain average stiffness on a small segment of the hand trajectory. The method is based on the analysis of the reassigned spectrogram of the arm's response to impulsive perturbations and can estimate arm stiffness on a trial-by-trial basis. Analytic and empirical methods are first derived and tested through modal analysis on synthetic data. The technique's accuracy and robustness are assessed by modeling the estimation of stiffness time profiles changing at different rates and affected by different noise levels. Our method obtains results comparable with two well-known regressive techniques. We also test how the technique can identify the viscoelastic component of non-linear and higher than second order systems with a non-parametrical approach. The technique proposed here is very impervious to noise and can be used easily for both postural and movement tasks. Estimations of stiffness profiles are possible with only one perturbation, making our method a useful tool for estimating limb stiffness during motor learning and adaptation tasks, and for understanding the modulation of stiffness in individuals with neurodegenerative diseases.

A preliminary study of the relation between adsorption and CP-MAS-NMR characteristics of fused silica model substrates

NARCIS (Netherlands)

Scholten, A.B.; Janssen, J.G.M.; Haan, de J.W.; Cramers, C.A.M.G.; Sandra, P.J.F.; Devos, G.; Sandra, P.

1993-01-01

The fumed silica model substrate Aerosil was trimethylsilylated to different extents and studied by the combination of IGC and 29Si CP-MAS-NMR. Dihydroxydisiloxane groups were shown to be chemically more reactive than monohydroxytrisiloxane groups. Chromatographic experiments showed that these

Angiotensin-converting enzyme 2, Angiotensin-(1-7) and Mas: new players of the Renin Angiotensin System

DEFF Research Database (Denmark)

Santos, Robson AS; Ferreira, Anderson J; Verano-Braga, Thiago

2013-01-01

/proliferative arm of the RAS consisting of ACE, Ang II and AT1 receptor. In this brief review, we will discuss recent findings related to the biological role of the ACE2/Ang-(1-7)/Mas arm in the cardiovascular and renal systems, as well as in metabolism. In addition, we will highlight the potential interactions...

Reklāmas ietekme uz patērētāju izvēles veikšanā

OpenAIRE

Asejevs, Aleksandrs

2012-01-01

Bakalaura darba tēma izvēlēta „Reklāmas ietekme uz patērētāju izvēles veikšanā”. Pastiprinoties konkurencei valstu iekšzemes tirgū, uzņēmumi savas preces un pakalpojumus virza globālajā tirgū. Starptautiskajā mārketingā reklāma tiek izmantota kā viens no mārketinga komunikācijas līdzekļiem, ar kura palīdzību uzņēmumi patērētajiem virzītu savas preces un pakalpojumus. Darba mērķis: balstoties uz veiktās aptaujas rezultātiem, izstrādāt priekšlikumus reklāmas pilnveidošanai Latvijā. Lai...

Matching of analytical and numerical solutions for neutron stars of arbitrary rotation

International Nuclear Information System (INIS)

Pappas, George

2009-01-01

We demonstrate the results of an attempt to match the two-soliton analytical solution with the numerically produced solutions of the Einstein field equations, that describe the spacetime exterior of rotating neutron stars, for arbitrary rotation. The matching procedure is performed by equating the first four multipole moments of the analytical solution to the multipole moments of the numerical one. We then argue that in order to check the effectiveness of the matching of the analytical with the numerical solution we should compare the metric components, the radius of the innermost stable circular orbit (R ISCO ), the rotation frequency and the epicyclic frequencies Ω ρ , Ω z . Finally we present some results of the comparison.

Matching of analytical and numerical solutions for neutron stars of arbitrary rotation

Energy Technology Data Exchange (ETDEWEB)

Pappas, George, E-mail: gpappas@phys.uoa.g [Section of Astrophysics, Astronomy, and Mechanics, Department of Physics, University of Athens, Panepistimiopolis Zografos GR15783, Athens (Greece)

2009-10-01

We demonstrate the results of an attempt to match the two-soliton analytical solution with the numerically produced solutions of the Einstein field equations, that describe the spacetime exterior of rotating neutron stars, for arbitrary rotation. The matching procedure is performed by equating the first four multipole moments of the analytical solution to the multipole moments of the numerical one. We then argue that in order to check the effectiveness of the matching of the analytical with the numerical solution we should compare the metric components, the radius of the innermost stable circular orbit (R{sub ISCO}), the rotation frequency and the epicyclic frequencies {Omega}{sub {rho}}, {Omega}{sub z}. Finally we present some results of the comparison.

Synthesis of High-Frequency Ground Motion Using Information Extracted from Low-Frequency Ground Motion

Science.gov (United States)

Iwaki, A.; Fujiwara, H.

2012-12-01

Broadband ground motion computations of scenario earthquakes are often based on hybrid methods that are the combinations of deterministic approach in lower frequency band and stochastic approach in higher frequency band. Typical computation methods for low-frequency and high-frequency (LF and HF, respectively) ground motions are the numerical simulations, such as finite-difference and finite-element methods based on three-dimensional velocity structure model, and the stochastic Green's function method, respectively. In such hybrid methods, LF and HF wave fields are generated through two different methods that are completely independent of each other, and are combined at the matching frequency. However, LF and HF wave fields are essentially not independent as long as they are from the same event. In this study, we focus on the relation among acceleration envelopes at different frequency bands, and attempt to synthesize HF ground motion using the information extracted from LF ground motion, aiming to propose a new method for broad-band strong motion prediction. Our study area is Kanto area, Japan. We use the K-NET and KiK-net surface acceleration data and compute RMS envelope at four frequency bands: 0.5-1.0 Hz, 1.0-2.0 Hz, 2.0-4.0 Hz, .0-8.0 Hz, and 8.0-16.0 Hz. Taking the ratio of the envelopes of adjacent bands, we find that the envelope ratios have stable shapes at each site. The empirical envelope-ratio characteristics are combined with low-frequency envelope of the target earthquake to synthesize HF ground motion. We have applied the method to M5-class earthquakes and a M7 target earthquake that occurred in the vicinity of Kanto area, and successfully reproduced the observed HF ground motion of the target earthquake. The method can be applied to a broad band ground motion simulation for a scenario earthquake by combining numerically-computed low-frequency (~1 Hz) ground motion with the empirical envelope ratio characteristics to generate broadband ground motion

Excitation of low-frequency residual currents at combination frequencies of an ionising two-colour laser pulse

Science.gov (United States)

Vvedenskii, N. V.; Kostin, V. A.; Laryushin, I. D.; Silaev, A. A.

2016-05-01

We have studied the processes of excitation of low-frequency residual currents in a plasma produced through ionisation of gases by two-colour laser pulses in laser-plasma schemes for THz generation. We have developed an analytical approach that allows one to find residual currents in the case when one of the components of a two-colour pulse is weak enough. The derived analytical expressions show that the effective generation of the residual current (and hence the effective THz generation) is possible if the ratio of the frequencies in the two-colour laser pulse is close to a rational fraction with a not very big odd sum of the numerator and denominator. The results of numerical calculations (including those based on the solution of the three-dimensional time-dependent Schrödinger equation) agree well with the analytical results.

1H MAS NMR (magic-angle spinning nuclear magnetic resonance) techniques for the quantitative determination of hydrogen types in solid catalysts and supports.

Science.gov (United States)

Kennedy, Gordon J; Afeworki, Mobae; Calabro, David C; Chase, Clarence E; Smiley, Randolph J

2004-06-01

Distinct hydrogen species are present in important inorganic solids such as zeolites, silicoaluminophosphates (SAPOs), mesoporous materials, amorphous silicas, and aluminas. These H species include hydrogens associated with acidic sites such as Al(OH)Si, non-framework aluminum sites, silanols, and surface functionalities. Direct and quantitative methodology to identify, measure, and monitor these hydrogen species are key to monitoring catalyst activity, optimizing synthesis conditions, tracking post-synthesis structural modifications, and in the preparation of novel catalytic materials. Many workers have developed several techniques to address these issues, including 1H MAS NMR (magic-angle spinning nuclear magnetic resonance). 1H MAS NMR offers many potential advantages over other techniques, but care is needed in recognizing experimental limitations and developing sample handling and NMR methodology to obtain quantitatively reliable data. A simplified approach is described that permits vacuum dehydration of multiple samples simultaneously and directly in the MAS rotor without the need for epoxy, flame sealing, or extensive glovebox use. We have found that careful optimization of important NMR conditions, such as magnetic field homogeneity and magic angle setting are necessary to acquire quantitative, high-resolution spectra that accurately measure the concentrations of the different hydrogen species present. Details of this 1H MAS NMR methodology with representative applications to zeolites, SAPOs, M41S, and silicas as a function of synthesis conditions and post-synthesis treatments (i.e., steaming, thermal dehydroxylation, and functionalization) are presented.

Experimental and numerical results of a high frequency rotating active magnetic refrigerator

DEFF Research Database (Denmark)

Lozano, Jaime; Engelbrecht, Kurt; Bahl, Christian

2012-01-01

Experimental results for a recently developed prototype magnetic refrigeration device at The Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators...

Experimental and numerical results of a high frequency rotating active magnetic refrigerator

DEFF Research Database (Denmark)

Lozano, Jaime; Engelbrecht, Kurt; Bahl, Christian R.H.

2014-01-01

Experimental results for a recently developed prototype magnetic refrigeration device at the Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators...

Numerical Studies of a Fluidic Diverter for Flow Control

Science.gov (United States)

Gokoglu, Suleyman A.; Kuczmarski, Maria A.; Culley, Dennis E.; Raghu, Surya

2009-01-01

The internal flow structure in a specific fluidic diverter is studied over a range from low subsonic to sonic inlet conditions by a time-dependent numerical analysis. The understanding will aid in the development of fluidic diverters with minimum pressure losses and advanced designs of flow control actuators. The velocity, temperature and pressure fields are calculated for subsonic conditions and the self-induced oscillatory behavior of the flow is successfully predicted. The results of our numerical studies have excellent agreement with our experimental measurements of oscillation frequencies. The acoustic speed in the gaseous medium is determined to be a key factor for up to sonic conditions in governing the mechanism of initiating the oscillations as well as determining its frequency. The feasibility of employing plasma actuation with a minimal perturbation level is demonstrated in steady-state calculations to also produce oscillation frequencies of our own choosing instead of being dependent on the fixed-geometry fluidic device.

Genotyping-by-sequencing (GBS), an ultimate marker-assisted selection (MAS) tool to accelerate plant breeding

OpenAIRE

He, Jiangfeng; Zhao, Xiaoqing; Laroche, André; Lu, Zhen-Xiang; Liu, HongKui; Li, Ziqin

2014-01-01

Marker-assisted selection (MAS) refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP), have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS) technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broad...

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine

DEFF Research Database (Denmark)

Hoseinzadeh, Bakhtyar; Silva, Filipe Faria Da; Bak, Claus Leth

2014-01-01

In close future, with high Wind Energy (WE) penetration in the power system, the burden of Load-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip the VSWT with LFC capability to support the grid during sudden variation in generation or load...... regulation. The proposed scheme demonstrates remarkable improvement transient state of both voltage and frequency profiles in comparison with conventional LFC designs provided by Central Power Plants (CPP) or Wind Power Plants (WPP). Numerical simulations carried out in DigSilent Power- Factory confirm...

Modulatory Effect of Aerobic Physical Activity on Synaptic Ultrastructure in the Old Mouse Hippocampus

Directory of Open Access Journals (Sweden)

Patrizia Fattoretti

2018-05-01

Full Text Available Aerobic physical exercise (APE leads to improved brain functions. To better understand the beneficial effect of APE on the aging brain, a morphometric study was carried out of changes in hippocampal synapses of old (>27 months Balb/c mice undergoing treadmill training (OTT for 4 weeks in comparison with old sedentary (OS, middle-aged sedentary (MAS and middle-aged treadmill training (MATT mice. The inner molecular layer of the hippocampal dentate gyrus (IMLDG and the molecular stratum of Ammon’s horn1 neurons (SMCA1 were investigated. The number of synapses per cubic micron of tissue (numeric density, Nv, overall synaptic area per cubic micron of tissue (surface density, Sv, average area of synaptic contact zones (S, and frequency (% of perforated synapses (PS were measured in electron micrographs of ethanol-phosphotungstic acid (E-PTA stained tissue. Data were analyzed with analysis of variance (ANOVA. In IMLDG, an effect of age was found for Nv and Sv, but not S and %PS. Similar results were found for exercise and the interaction of age and exercise. In post hoc analysis Nv was higher (60.6% to 75.1%; p < 0.001 in MATT vs. MAS, OS and OTT. Sv was higher (32.3% to 54.6%; p < 0.001 in MATT vs. MAS, OS and OTT. In SMCA1, age affected Nv, Sv and %PS, but not S. The effect of exercise was significant for Sv only. The interaction of age and exercise was significant for Nv, Sv and %PS. In post hoc analysis Nv was lower in OS vs. MAS, MATT and OTT (−26.1% to −32.1%; p < 0.038. MAS and OTT were similar. Sv was lower in OS vs. MAS, MATT and OTT (−23.4 to −30.3%, p < 0.004. MAS and OTT were similar. PS frequency was higher in OS vs. MAS, MATT and OTT (48.3% to +96.6%, p < 0.023. APE positively modulated synaptic structural dynamics in the aging hippocampus, possibly in a region-specific way. The APE-associated reduction in PS frequency in SMCA1 of old mice suggests that an increasing complement of PS is a compensatory phenomenon to maintain

Genotyping by sequencing (GBS, an ultimate marker-assisted selection (MAS tool to accelerate plant breeding

Directory of Open Access Journals (Sweden)

Jiangfeng eHe

2014-09-01

Full Text Available Marker-assisted selection (MAS refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP, have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broaden NGS usages to large crop genomes such as maize and wheat, genotyping by sequencing (GBS has been developed and applied in sequencing multiplexed samples that combine molecular marker discovery and genotyping. GBS is a novel application of NGS protocols for discovering and genotyping SNPs in crop genomes and populations. The GBS approach includes the digestion of genomic DNA with restriction enzymes followed by the ligation of barcode adapter, PCR amplification and sequencing of the amplified DNA pool on a single lane of flow cells. Bioinformatic pipelines are needed to analyze and interpret GBS datasets. As an ultimate MAS tool and a cost-effective technique, GBS has been successfully used in implementing genome-wide association study (GWAS, genomic diversity study, genetic linkage analysis, molecular marker discovery and genomic selection (GS under a large scale of plant breeding programs.

Genotyping-by-sequencing (GBS), an ultimate marker-assisted selection (MAS) tool to accelerate plant breeding.

Science.gov (United States)

He, Jiangfeng; Zhao, Xiaoqing; Laroche, André; Lu, Zhen-Xiang; Liu, HongKui; Li, Ziqin

2014-01-01

Marker-assisted selection (MAS) refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP), have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS) technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broaden NGS usages to large crop genomes such as maize and wheat, genotyping-by-sequencing (GBS) has been developed and applied in sequencing multiplexed samples that combine molecular marker discovery and genotyping. GBS is a novel application of NGS protocols for discovering and genotyping SNPs in crop genomes and populations. The GBS approach includes the digestion of genomic DNA with restriction enzymes followed by the ligation of barcode adapter, PCR amplification and sequencing of the amplified DNA pool on a single lane of flow cells. Bioinformatic pipelines are needed to analyze and interpret GBS datasets. As an ultimate MAS tool and a cost-effective technique, GBS has been successfully used in implementing genome-wide association study (GWAS), genomic diversity study, genetic linkage analysis, molecular marker discovery and genomic selection under a large scale of plant breeding programs.

Numerical modeling of an enhanced very early time electromagnetic (VETEM) prototype system

Science.gov (United States)

Cui, T.J.; Chew, W.C.; Aydiner, A.A.; Wright, D.L.; Smith, D.V.; Abraham, J.D.

2000-01-01

In this paper, two numerical models are presented to simulate an enhanced very early time electromagnetic (VETEM) prototype system, which is used for buried-object detection and environmental problems. Usually, the VETEM system contains a transmitting loop antenna and a receiving loop antenna, which run on a lossy ground to detect buried objects. In the first numerical model, the loop antennas are accurately analyzed using the Method of Moments (MoM) for wire antennas above or buried in lossy ground. Then, Conjugate Gradient (CG) methods, with the use of the fast Fourier transform (FFT) or MoM, are applied to investigate the scattering from buried objects. Reflected and scattered magnetic fields are evaluated at the receiving loop to calculate the output electric current. However, the working frequency for the VETEM system is usually low and, hence, two magnetic dipoles are used to replace the transmitter and receiver in the second numerical model. Comparing these two models, the second one is simple, but only valid for low frequency or small loops, while the first modeling is more general. In this paper, all computations are performed in the frequency domain, and the FFT is used to obtain the time-domain responses. Numerical examples show that simulation results from these two models fit very well when the frequency ranges from 10 kHz to 10 MHz, and both results are close to the measured data.

Numerical solution of a coefficient inverse problem with multi-frequency experimental raw data by a globally convergent algorithm

Science.gov (United States)

Nguyen, Dinh-Liem; Klibanov, Michael V.; Nguyen, Loc H.; Kolesov, Aleksandr E.; Fiddy, Michael A.; Liu, Hui

2017-09-01

We analyze in this paper the performance of a newly developed globally convergent numerical method for a coefficient inverse problem for the case of multi-frequency experimental backscatter data associated to a single incident wave. These data were collected using a microwave scattering facility at the University of North Carolina at Charlotte. The challenges for the inverse problem under the consideration are not only from its high nonlinearity and severe ill-posedness but also from the facts that the amount of the measured data is minimal and that these raw data are contaminated by a significant amount of noise, due to a non-ideal experimental setup. This setup is motivated by our target application in detecting and identifying explosives. We show in this paper how the raw data can be preprocessed and successfully inverted using our inversion method. More precisely, we are able to reconstruct the dielectric constants and the locations of the scattering objects with a good accuracy, without using any advanced a priori knowledge of their physical and geometrical properties.

"Okarte" reklāmas kampaņas "Onedēļa" komunikācija internetā 2013. gadā

OpenAIRE

Volonts, Kaspars

2013-01-01

Bakalaura darba tēma ir “"Okarte" reklāmas kampaņa "Onedēļa" komunikācija internetā 2013. gadā”. Tēma par zīmola komunikāciju interneta vidē ir aktuāla, jo interneta lietotāju skaits Latvijā aug katru gadu. Latvijā strādājošiem zīmoliem arvien biežāk jāsaskarās ar savu mērķauditoriju, izmantojot internetu. Bakalaura darba pētījuma mērķis ir izpētīt kā “Latvijas Mobilā Telefona” priekšapmaksas kartes “Okarte” zīmols komunicē savu tēlu un reklāmas kampaņu interneta vidē 2013.gadā. Ša...

27Al Magic Angle Spinning–Nuclear Magnetic Resonance (MAS-NMR) Analyses Applied to Historical Mortars

Czech Academy of Sciences Publication Activity Database

Hanzlíček, Tomáš; Perná, Ivana; Brus, Jiří

2013-01-01

Roč. 7, č. 2 (2013), s. 153-164 ISSN 1558-3058 R&D Projects: GA AV ČR IAA300460702 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z40500505 Keywords : mortars * magic angle spinning –nuclear magnetic resonance (MAS-NMR) in solid state * alumina-silicates Subject RIV: DM - Solid Waste and Recycling Impact factor: 0.714, year: 2013 http://www.tandfonline.com/doi/abs/10.1080/15583058.2011.624253

Active and passive fire protection system in academic building KH. Mas Mansur, Islamic University of Indonesia

Directory of Open Access Journals (Sweden)

Suryoputro M. Ragil

2018-01-01

Full Text Available According to the theory of fire triangle, the existence of combustible materials, heat, and oxygen can cause fire disaster. KH. Mas Mansur building, Islamic University of Indonesia has a fire protection, but rarely to be checked regularly and the number of equipment is less standard as well as the lack of an evacuation route map to facilitate the evacuation process. Inside the building also does not provide safety signs such as the evacuation directions, exit, and warning in case of fire. Therefore, researchers analysed the infrastructure of prevention and control in the building KH. Mas Mansur. Researchers used the method of observation, interviews, and checklist to know the condition directly, and compare with the standard regulations. Results concordance rate of existing infrastructure is 67% fire extinguisher, hydrant box 56%, 71% alarms, sprinkler 0%, 40% detectors, emergency doors 71%, 50% emergency stairs, assembly point 0% and directions 0%. The current results were below the standard of at least 80%. As for recommendations, researchers create a new evacuation map then put the existing infrastructure according to standard regulations, and it had consulted with the specialist of Occupational Safety and Health in the field of fire.

Electromagnetic Scattering Analysis of Coated Conductors With Edges Using the Method of Auxiliary Sources (MAS) in Conjunction With the Standard Impedance Boundary Condition (SIBC)

DEFF Research Database (Denmark)

Anastassiu, H.T.; D.I.Kaklamani, H.T.; Economou, D.P.

2002-01-01

A novel combination of the method of auxiliary sources (MAS) and the standard impedance boundary condition (SIBC) is employed in the analysis of transverse magnetic (TM) plane wave scattering from infinite, coated, perfectly conducting cylinders with square cross sections. The scatterer is initia......A novel combination of the method of auxiliary sources (MAS) and the standard impedance boundary condition (SIBC) is employed in the analysis of transverse magnetic (TM) plane wave scattering from infinite, coated, perfectly conducting cylinders with square cross sections. The scatterer...

Antioxidant capacity of cornelian cherry (Cornus mas L.) - comparison between permanganate reducing antioxidant capacity and other antioxidant methods.

Science.gov (United States)

Popović, Boris M; Stajner, Dubravka; Slavko, Kevrešan; Sandra, Bijelić

2012-09-15

Ethanol extracts (80% in water) of 10 cornelian cherry (Cornus mas L.) genotypes were studied for antioxidant properties, using methods including DPPH(), ()NO, O(2)(-) and ()OH antiradical powers, FRAP, total phenolic and anthocyanin content (TPC and ACC) and also one relatively new, permanganate method (permanganate reducing antioxidant capacity-PRAC). Lipid peroxidation (LP) was also determined as an indicator of oxidative stress. The data from different procedures were compared and analysed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). Significant positive correlations were obtained between TPC, ACC and DPPH(), ()NO, O(2)(-), and ()OH antiradical powers, and also between PRAC and TPC, ACC and FRAP. PCA found two major clusters of cornelian cherry, based on antiradical power, FRAP and PRAC and also on chemical composition. Chemometric evaluation showed close interdependence between PRAC method and FRAP and ACC. There was a huge variation between C. mas genotypes in terms of antioxidant activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Integral methods in low-frequency electromagnetics

CERN Document Server

Solin, Pavel; Karban, Pavel; Ulrych, Bohus

2009-01-01

A modern presentation of integral methods in low-frequency electromagnetics This book provides state-of-the-art knowledge on integral methods in low-frequency electromagnetics. Blending theory with numerous examples, it introduces key aspects of the integral methods used in engineering as a powerful alternative to PDE-based models. Readers will get complete coverage of: The electromagnetic field and its basic characteristics An overview of solution methods Solutions of electromagnetic fields by integral expressions Integral and integrodifferential methods

Brain angiotensin-(1-7)/Mas axis: A new target to reduce the cardiovascular risk to emotional stress.

Science.gov (United States)

Fontes, Marco Antônio Peliky; Martins Lima, Augusto; Santos, Robson Augusto Souza dos

2016-04-01

Emotional stress is now considered a risk factor for several diseases including cardiac arrhythmias and hypertension. It is well known that the activation of neuroendocrine and autonomic mechanisms features the response to emotional stress. However, its link to cardiovascular diseases and the regulatory mechanisms involved remain to be further comprehended. The renin-angiotensin system (RAS) plays an important role in homeostasis on all body systems. Specifically in the brain, the RAS regulates a number of physiological aspects. Recent data indicate that the activation of angiotensin-converting enzyme/angiotensin II/AT1 receptor axis facilitates the emotional stress responses. On the other hand, growing evidence indicates that its counterregulatory axis, the angiotensin-converting enzyme 2 (ACE2)/(Ang)iotensin-(1-7)/Mas axis, reduces anxiety and attenuates the physiological responses to emotional stress. The present review focuses on angiotensin-(1-7)/Mas axis as a promising target to attenuate the physiological response to emotional stress reducing the risk of cardiovascular diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental and numerical study of guided wave propagation in a thin metamaterial plate

International Nuclear Information System (INIS)

Zhu, R.; Huang, G.L.; Huang, H.H.; Sun, C.T.

2011-01-01

In this Letter, both in-plane and out-of-plane guided waves in a thin plate with local resonators are studied numerically and experimentally. Through the numerical simulation, a new metamaterial plate design is achieved for a low-frequency bandgap in both in-plane and out-of-plane guided waves. Experiments were conducted to validate the numerical design. In the experiment, piezoelectric transducers were used to generate and receive guided wave signals. The results show that the numerical predictions are in very good agreement with the experimental measurements. Specifically, the connection between the local resonance in the thin plate and its wave attenuation mechanism was discussed. -- Highlights: → Both in-plane and out-of-plane guided waves in a thin plate with local resonators are studied numerically and experimentally. → A new metamaterial plate design is achieved for a low-frequency bandgap in both in-plane and out-of-plane guided waves. → Experiments were conducted to validate the numerical design. → The connection between the local resonance in the thin plate and its wave attenuation mechanism was investigated.

Numerical analysis of Swiss roll metamaterials

International Nuclear Information System (INIS)

Demetriadou, A; Pendry, J B

2009-01-01

A Swiss roll metamaterial is a resonant magnetic medium, with a negative magnetic permeability for a range of frequencies, due to its self-inductance and self-capacitance components. In this paper, we discuss the band structure, S-parameters and effective electromagnetic parameters of Swiss roll metamaterials, with both analytical and numerical results, which show an exceptional convergence.

Lyapunov exponent of the random frequency oscillator: cumulant expansion approach

International Nuclear Information System (INIS)

Anteneodo, C; Vallejos, R O

2010-01-01

We consider a one-dimensional harmonic oscillator with a random frequency, focusing on both the standard and the generalized Lyapunov exponents, λ and λ* respectively. We discuss the numerical difficulties that arise in the numerical calculation of λ* in the case of strong intermittency. When the frequency corresponds to a Ornstein-Uhlenbeck process, we compute analytically λ* by using a cumulant expansion including up to the fourth order. Connections with the problem of finding an analytical estimate for the largest Lyapunov exponent of a many-body system with smooth interactions are discussed.

Interneta vietne "YouTube" kā reklāmas un infoizklaides kanāls 2008. gada pirmajā ceturksnī

OpenAIRE

Reinberga, Ieva

2008-01-01

Bakalaura darba mērķis ir izpētīt, kādus komunikācijas uzdevumus veikusi interneta vietne www.YouTube.com – reklāmas, izklaides, informācijas vai citus - laika periodā no 2008. gada 1. janvāra līdz 2008. gada 31. martam, konstatējot vietnes saturā reklāmai, izklaidei un informācijai raksturīgās iezīmes. Pētījums tiek balstīts uz reklāmas, infoklaides, interneta tehnoloģiju, spēles teorijas, populārās kultūras teorijām, kā arī, atsaucoties uz līdzšinējām analīzēm par vietnes YouTube vēstur...

MUNICIPAL ENVIRONMENTAL MANAGEMENT: A PROPOSAL OF INSTRUMENTS FOR DIAGNOSIS OF PUBLIC ENVIRONMENTAL POLICIES IN THE METROPOLITAN AREA OF SALVADOR (MAS

Directory of Open Access Journals (Sweden)

Tânia Cristina Azevedo

2016-04-01

Full Text Available The aim in this paper is to propose a model for mapping strategies of municipal environmental management for local environmental public policies. To do so, the study adopted a theoretical approach. More specifically, there is discussion on the concepts of public policies and the scenario of the Brazilian municipal environmental management, a brief history of the aspects that involve current national environmental policies. Methodologically, a bibliographical study was carried out through a literature review, which enabled the proposal of instruments for mapping actions and strategies of environmental management in the municipalities of the Metropolitan Area of Salvador (MAS. This theoretical study resulted in the creation of a model form that will be used by empirical researches for mapping the environmental public policies in the MAS City Halls.

New perspectives of 19F MAS NMR in the characterization of amorphous forms of atorvastatin in dosage formulations

Czech Academy of Sciences Publication Activity Database

Brus, Jiří; Urbanová, Martina; Šeděnková, Ivana; Brusová, H.

2011-01-01

Roč. 409, 1/2 (2011), s. 62-74 ISSN 0378-5173 R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : 19F MAS NMR * factor analysis * polymorphism Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.350, year: 2011

Ab initio study of structure and stability of thiocarbonates, thiosilicates, thionitrates, thiophosphates, thioborates and thioaluminates L2AS3 and MAS3 (L=Li, Na; M=Be, Mg; A=C, Si, N+, P+, B-, Al-)

International Nuclear Information System (INIS)

Charkin, D.O.; Makki, M.L.; Charkin, O.P.

1998-01-01

Nonempiric calculations of potential energy surfaces for the family of isoelectron molecules and ions of lithium and sodium thiosalts of the MAS 3 type atr carried out within the frames of the MP2/6-31G * +ZPE(HF/6-31G * ) and MP4SDTQ/6-31(+)G + //MP2/6-31G * +ZPE(MP2/6-31G * ) approximations. Plane structures C s with disulfide bridge S-S are found to be most preferable for thionitrates, angular structure C s with one bridge and two end sulfur atoms - for thioborate negative ions BeBS 3 , MgBS 3 and molecules B 2 S 3 , Al 2 S 3 and structures C 2v with bidentate coordination of cations and thioanion AS 3 n- - for remaining systems. Equilibrium geometric parameters and relative energies of isomers, energies of their decomposition, frequencies and IR-intensities of normal oscillations are determined, effect of electron correlation on the calculation results is analyzed. Ortho-meta-isomery in thioborates and thioaluminates, deformation and polarization of thioanions under the effect of alkali and alkaline-earth cations and trends in chomping molecular properties in various series of the L 2 AS 3 and MAS 3 salts are discussed

PEMANFAATAN TANAMAN ATRAKTAN MENGENDALIKAN HAMA KEONG MAS PADI

Directory of Open Access Journals (Sweden)

Ameilia Zuliyanti Siregar

2018-01-01

In Indonesia, many plantation as use as beneficial plants. This study aims to obtain an effective formula that can be used as a biopesticide to control snail pests during the vegetative phase from May to July 2017 using random non-factorial methods at two rice planting locations in the Village Lae parira, Dairi, North Sumatra. Design with 6 treatments and 3 replicates (ie control, neem leaves (Azadirachta indica, tobacco leaf (Nicotiana tabacum, sweet potato leaf (Manihot glaziovii, noni fruit, Morinda citrifolia, and betel nut (Areca catechu and papaya (Carica papaya as an eco-friendly herbaceous and biopesticide. Based on the study recorded in sampling for 7 days with 6 treatments had significant effect on the percentage affected by the clump of rice attacked and the percentage of death. Pearson correlation value recorded percentage of death and percentage of impacted  showed a very significant relationship. Neem is the best biopesticide in controlling mollusicides, followed by betel nuts, tobacco, poisonous yams and noni. Death of 100% snail mas will prevent damage to the clump of rice plants Dairi, North Sumatra. All biopesticide treatments were tested to control snail pests in rice plants that will increase agicultural productivity in maintaining food security in Dairi, North Sumatra.

Mobilā reklāma kā mobilo priekšapmaksas sarunu karšu reklāmas komunikācijas instruments: Y paaudzes radītās iespējas

OpenAIRE

Daudze, Anita

2009-01-01

Bakalaura darba temats ir „Mobilā reklāma kā mobilo priekšapmaksas sarunu karšu reklāmas komunikācijas instruments: Y paaudzes radītās iespējas”. Pētījuma problēma ir mobilās reklāmas piemērotība komunikācijai ar Y paaudzes pārstāvjiem – mobilo priekšapmaksas sarunu karšu lietotājiem. Darba teorētiskais pamatojums balstīts uz Y paaudzes jēdziena izpratni, mobilā telefona kā reklāmas komunikācijas kanāla aplūkošanu, kā arī mobilā mārketinga un reklāmas pamatprincipu izklāstu. Darbā izman...

The Brunt–Väisälä frequency of rotating tokamak plasmas

International Nuclear Information System (INIS)

Haverkort, J.W.; Blank, H.J. de; Koren, B.

2012-01-01

The continuous spectrum of analytical toroidally rotating magnetically confined plasma equilibria is investigated analytically and numerically. In the presence of purely toroidal flow, the ideal magnetohydrodynamic equations leave the freedom to specify which thermodynamic quantity is constant on the magnetic surfaces. Introducing a general parametrization of this quantity, analytical equilibrium solutions are derived that still posses this freedom. These equilibria and their spectral properties are shown to be ideally suited for testing numerical equilibrium and stability codes including toroidal rotation. Analytical expressions are derived for the low-frequency continuous Alfvén spectrum. These expressions still allow one to choose which quantity is constant on the magnetic surfaces of the equilibrium, thereby generalizing previous results. The centrifugal convective effect is shown to modify the lowest Alfvén continuum branch to a buoyancy frequency, or Brunt–Väisälä frequency. A comparison with numerical results for the case that the specific entropy, the temperature, or the density is constant on the magnetic surfaces yields excellent agreement, showing the usefulness of the derived expressions for the validation of numerical codes.

Frequency Dependent Nudging of Hydrographic Data Into a Numerical Model of the North Atlantic

Science.gov (United States)

Thompson, K. R.; Wright, D. G.

2002-12-01

Nudging is one of the simplest ways of assimilating data into ocean models and it has been used for many years in studies of large-scale ocean circulation. One of its drawbacks is the suppression of eddies when nudging an eddy-permitting ocean model strongly toward an observed seasonal climatology. We propose a straightforward extension of nudging in which the model's climatology, rather than its instantaneous state, is nudged toward the observed seasonal climatology. In effect we propose nudging in specific frequency bands that are centered on the discrete frequencies evident in the observed climatology (e.g. 0, 1/12 and 1/6 cycles per month). This extension of conventional nudging allows the difference between the observed and modeled climatologies arbitrarily to be made small while allowing variations outside the selected frequency bands to evolve freely. We show how the method can be implemented efficiently in complex models using a Kalman filter and also discuss the benefits of spatially smoothing the nudges. We conclude with a demonstration of frequency dependent nudging using a 1/3 degree model of the North Atlantic.

Numerical Simulation of Plasma Antenna with FDTD Method

International Nuclear Information System (INIS)

Chao, Liang; Yue-Min, Xu; Zhi-Jiang, Wang

2008-01-01

We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconBgurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design

Numerical simulation of plasma antenna with FDTD method

International Nuclear Information System (INIS)

Liang Chao; Xu Yuemin; Wang Zhijiang

2008-01-01

We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconfigurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design. (authors)

Un lote de armamento ibérico procedente de la necrópolis del Mas de Barberán (Nogueruelas, Teruel

Directory of Open Access Journals (Sweden)

Izquierdo Peraile, Isabel

1999-12-01

Full Text Available In this paper we publish an Ibenan set of weapons -swords, lances and dagger essentially-, coming from the cemetery of the settlement so-called Mas de Barberán (Nogueruelas, Teruel. An anthropomorphic stele with an inscription recently studied is associated to the same site. This stele represents an armed with disk-cuirass masculine personage.

En este trabajo presentamos un lote inédito de armamento ibérico espadas, lanzas y puñal esencialmente procedente de la necrópolis correspondiente al poblado del Mas de Barberán (Nogueruelas, Teruel. Al mismo yacimiento se asocia la estela antropomorfa con inscripción que representa un personaje masculino armado con disco-coraza, recientemente estudiada.

Numerical analysis of the resonance mechanism of the lumped parameter system model for acoustic mine detection

International Nuclear Information System (INIS)

Wang Chi; Zhou Yu-Qiu; Shen Gao-Wei; Wu Wen-Wen; Ding Wei

2013-01-01

The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the ''soil-mine'' system could be equivalent to a damping ''mass-spring'' resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil—mine system could be investigated by changing the parameter setup in a flexible manner. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Distributed Cooperation Solution Method of Complex System Based on MAS

Science.gov (United States)

Weijin, Jiang; Yuhui, Xu

To adapt the model in reconfiguring fault diagnosing to dynamic environment and the needs of solving the tasks of complex system fully, the paper introduced multi-Agent and related technology to the complicated fault diagnosis, an integrated intelligent control system is studied in this paper. Based on the thought of the structure of diagnostic decision and hierarchy in modeling, based on multi-layer decomposition strategy of diagnosis task, a multi-agent synchronous diagnosis federation integrated different knowledge expression modes and inference mechanisms are presented, the functions of management agent, diagnosis agent and decision agent are analyzed, the organization and evolution of agents in the system are proposed, and the corresponding conflict resolution algorithm in given, Layered structure of abstract agent with public attributes is build. System architecture is realized based on MAS distributed layered blackboard. The real world application shows that the proposed control structure successfully solves the fault diagnose problem of the complex plant, and the special advantage in the distributed domain.

The angiotensin-(1-7/Mas axis counteracts angiotensin II-dependent and –independent pro-inflammatory signaling in human vascular smooth muscle cells

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Laura A Villalobos

2016-12-01

Full Text Available Background and aims: Targeting inflammation is nowadays considered as a challenging pharmacological strategy to prevent or delay the development of vascular diseases. Angiotensin-(1-7 is a member of the renin-angiotensin system (RAS that binds Mas receptors and has gained growing attention in the last years as a regulator of vascular homeostasis. Here, we explored the capacity of Ang-(1-7 to counteract human aortic smooth muscle cell (HASMC inflammation triggered by RAS-dependent and –independent stimuli, such as Ang II or interleukin (IL-1.Methods and Results: In cultured HASMC, the expression of iNOS and the release of nitric oxide were stimulated by both Ang II and IL-1, as determined by Western blot and indirect immunofluorescence or the Griess method, respectively. iNOS induction was inhibited by Ang-(1-7 in a concentration-dependent manner. This effect was equally blocked by two different Mas receptor antagonists, A779 and D-Pro7-Ang-(1-7, suggesting the participation of a unique Mas receptor subtype. Using pharmacological inhibitors, the induction of iNOS was proven to rely on the consecutive upstream activation of NADPH oxidase and NF-B. Indeed, Ang-(1-7 markedly inhibited the activation of the NADPH oxidase and subsequently of NF-B, as determined by lucigenin-derived chemiluminiscence and electromobility shift assay, respectively.Conclusion: Ang-(1-7 can act as a counter-regulator of the inflammation of vascular smooth muscle cells triggered by Ang II, but also by other stimuli beyond the RAS. Activating or mimicking the Ang-(1-7/Mas axis may represent a pharmacological opportunity to attenuate the pro-inflammatory environment that promotes and sustains the development of vascular diseases.

Frequency conversion of structured light.

Science.gov (United States)

Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P

2016-02-15

Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.

Radio-frequency wave enhanced runaway production rate

International Nuclear Information System (INIS)

Chan, V.S.; McClain, F.W.

1983-01-01

Enhancement of runaway electron production (over that of an Ohmic discharge) can be achieved by the addition of radio-frequency waves. This effect is studied analytically and numerically using a two-dimensional Fokker--Planck quasilinear equation

Numerical Cerebrospinal System Modeling in Fluid-Structure Interaction.

Science.gov (United States)

Garnotel, Simon; Salmon, Stéphanie; Balédent, Olivier

2018-01-01

Cerebrospinal fluid (CSF) stroke volume in the aqueduct is widely used to evaluate CSF dynamics disorders. In a healthy population, aqueduct stroke volume represents around 10% of the spinal stroke volume while intracranial subarachnoid space stroke volume represents 90%. The amplitude of the CSF oscillations through the different compartments of the cerebrospinal system is a function of the geometry and the compliances of each compartment, but we suspect that it could also be impacted be the cardiac cycle frequency. To study this CSF distribution, we have developed a numerical model of the cerebrospinal system taking into account cerebral ventricles, intracranial subarachnoid spaces, spinal canal and brain tissue in fluid-structure interactions. A numerical fluid-structure interaction model is implemented using a finite-element method library to model the cerebrospinal system and its interaction with the brain based on fluid mechanics equations and linear elasticity equations coupled in a monolithic formulation. The model geometry, simplified in a first approach, is designed in accordance with realistic volume ratios of the different compartments: a thin tube is used to mimic the high flow resistance of the aqueduct. CSF velocity and pressure and brain displacements are obtained as simulation results, and CSF flow and stroke volume are calculated from these results. Simulation results show a significant variability of aqueduct stroke volume and intracranial subarachnoid space stroke volume in the physiological range of cardiac frequencies. Fluid-structure interactions are numerous in the cerebrospinal system and difficult to understand in the rigid skull. The presented model highlights significant variations of stroke volumes under cardiac frequency variations only.

Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis

Czech Academy of Sciences Publication Activity Database

Urbanová, Martina; Brus, Jiří; Šeděnková, Ivana; Policianová, Olivia; Kobera, Libor

2013-01-01

Roč. 100, 1 January (2013), s. 59-66 ISSN 1386-1425 R&D Projects: GA ČR GPP106/11/P426; GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : solid-state NMR * factor analysis * 19F MAS NMR Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 2.129, year: 2013

Frequency adjustable MEMS vibration energy harvester

Science.gov (United States)

Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

2016-10-01

Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

Frequency adjustable MEMS vibration energy harvester

International Nuclear Information System (INIS)

Podder, P; Constantinou, P; Roy, S; Amann, A

2016-01-01

Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

Application of Numerical Dispersion Compensation of the Yee-FDTD Algorithm on Elongated Domains

DEFF Research Database (Denmark)

Franek, Ondrej; Zhang, Shuai; Olesen, Kim

2017-01-01

A postprocessing method to compensate for the numerical dispersion of the Yee-FDTD scheme is presented. The method makes use of frequency domain deconvolution of the erroneous phase shift from the obtained results and can be applied on certain specific conditions, such as for simulations on elong......A postprocessing method to compensate for the numerical dispersion of the Yee-FDTD scheme is presented. The method makes use of frequency domain deconvolution of the erroneous phase shift from the obtained results and can be applied on certain specific conditions, such as for simulations...

Perilaku Alturisme Karyawan (Studi Kasus pada Mandor Perkebunan Sawit Perseroan Terbatas (PT.Tribuana Mas Kabupaten Tapin

Directory of Open Access Journals (Sweden)

Asty Wulandari

2017-11-01

Full Text Available One of the tasks of developing into adulthood is to work to meet the needs of his life. Technological advances, materialism, hedonism and the demands of the post-industrial society's needs make some people work brutally for what they want to be fulfilled. Even people are apathetic to the surrounding environment. Nevertheless, there are still a handful of employees who care about their environmental conditions by behaving altruism as happened in PT.Tribuana Mas (TBM. The purpose of this study is to describe employee altruism behavior and explore the factors that encourage employees to behave altruism. The results of the research on 3 employees of PT.Tribuana Mas plantation, Afdeling Juliet conducted qualitatively (nonparticipant observation and in-depth interview, altruism behavioral components are mostly the same, that is behaving helpfully, considering the rights and welfare of others, sharing and honesty. While the different components are seen from the behavior of donating & generosity and Cooperation. Components of altruism behavior reflected on the employees are also in accordance with the teachings of Islam, the namely charity with the foundation of god (ikhlas and there are still nuanced humanity. It is influenced by various factors, both situational (external and within (internal

Mas d’Is (Penàguila, Alicante: farms and Early Neolithic causewayed camps in the Serpis valley

Directory of Open Access Journals (Sweden)

Bernabeu Auban, Joan

2003-12-01

Full Text Available In this paper, results from recent archaeological field work carried out in the Neolithic village of Mas d’Is (Penàguila, Alicante are presented. We focus on an important set of domestic and monumental architectural structures. Integration of data from the site in a regional context allows us to rethink the social relations of the first farmers in the area. At the same time, radiocarbon data from our excavations show a finer chronology of the neolithization in Western Mediterranean, and what is more important to approach its historical process.

En este trabajo presentamos los resultados de los recientes trabajos llevados a cabo en la aldea neolítica de Mas d’Is (Penàguila, Alicante, centrándonos en las estructuras documentadas. La integración de los datos obtenidos en un contexto regional nos permiten plantear algunas reflexiones sobre la Arqueología social de los primeros agricultores, al tiempo que las dataciones radiocarbónicas permiten ir ajustando la cronología de la neolitización del Mediterráneo Occidental, así como el desarrollo de dicho proceso histórico.

Prototype bucket foundation for wind turbines - natural frequency estimation

Energy Technology Data Exchange (ETDEWEB)

Ibsen, Lars Bo; Liingaard, M.

2006-12-15

The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The natural frequencies are initially estimated by means of experimental Output-only Modal analysis. The experimental estimates are then compared with numerical simulations of the suction caisson foundation and the wind turbine. The numerical model consists of a finite element section for the wind turbine tower and nacelle. The soil-structure interaction of the soil-foundation section is modelled by lumped-parameter models capable of simulating dynamic frequency dependent behaviour of the structure-foundation system. (au)

A Numerical Matrix-Based method in Harmonic Studies in Wind Power Plants

DEFF Research Database (Denmark)

Dowlatabadi, Mohammadkazem Bakhshizadeh; Hjerrild, Jesper; Kocewiak, Łukasz Hubert

2016-01-01

In the low frequency range, there are some couplings between the positive- and negative-sequence small-signal impedances of the power converter due to the nonlinear and low bandwidth control loops such as the synchronization loop. In this paper, a new numerical method which also considers...... these couplings will be presented. The numerical data are advantageous to the parametric differential equations, because analysing the high order and complex transfer functions is very difficult, and finally one uses the numerical evaluation methods. This paper proposes a numerical matrix-based method, which...

Effective collision frequency of electrons in noble gases

International Nuclear Information System (INIS)

Baille, P.; Chang, J.-S.; Claude, A.; Yau, A.W.; Hobson, R.M.; Ogram, G.L.

1981-01-01

The electron-neutral collision frequency in the noble gases has been calculated using recent numerical results for momentum transfer cross sections by assuming a Maxwellian distribution of electron velocities. In all these gases, except for argon, good agreement is obtained with most previously published experimental and theoretical data. Mean free path, mobilities and diffusion coefficients are also calculated from the resulting effective collision frequencies. The empirical formulae are presented for an electron temperature dependence of the electron-neutral collision frequency for all noble gases up to Tsub(e) < approximately 25.000 K. (author)

Electron energy distributions and excitation rates in high-frequency argon discharges

International Nuclear Information System (INIS)

Ferreira, C.M.; Loureiro, J.

1983-06-01

The electron energy distribution functions and rate coefficients for excitation and ionisation in argon under the action of an uniform high-frequency electric field were calculated by numerically solving the homogeneous Boltzmann equation. Analytic calculations in the limiting cases ω>>νsub(c) and ω<<νsub(c), where ω is the wave angular frequency and νsub(c) is the electron-neutral collision frequency for momentum transfer, are also presented and shown to be in very good agreement with the numerical computations. The results reported here are relevant for the modelling of high-frequency discharges in argon and, in particular, for improving recent theoretical descriptions of a plasma column sustained by surface microwaves. The properties of surface wave produced plasmas make them interesting as possible substitutes for other more conventional plasma sources for such important applications as plasma chemistry laser excitation, plasma etching spectroscopic sources etc...

Model predictions for atmospheric air breakdown by radio-frequency excitation in large gaps

Science.gov (United States)

Nguyen, H. K.; Mankowski, J.; Dickens, J. C.; Neuber, A. A.; Joshi, R. P.

2017-07-01

The behavior of the breakdown electric field versus frequency (DC to 100 MHz) for different gap lengths has been studied numerically at atmospheric pressure. Unlike previous reports, the focus here is on much larger gap lengths in the 1-5 cm range. A numerical analysis, with transport coefficients obtained from Monte Carlo calculations, is used to ascertain the electric field thresholds at which the growth and extinction of the electron population over time are balanced. Our analysis is indicative of a U-shaped frequency dependence, lower breakdown fields with increasing gap lengths, and trends qualitatively similar to the frequency-dependent field behavior for microgaps. The low frequency value of ˜34 kV/cm for a 1 cm gap approaches the reported DC Paschen limit.

1 H MAS NMR study of structure of hybrid siloxane-based networks and the interaction with quartz filler

Czech Academy of Sciences Publication Activity Database

Brus, Jiří; Škrdlantová, M.

2001-01-01

Roč. 281, 1-3 (2001), s. 61-71 ISSN 0022-3093 R&D Projects: GA ČR GA203/98/P290; GA AV ČR KSK2050602 Institutional research plan: CEZ:AV0Z4050913 Keywords : hybrid siloxane networks * 1 H MAS NMR spectroscopy * hydrogen bonds Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.363, year: 2001

Frequency interval balanced truncation of discrete-time bilinear systems

DEFF Research Database (Denmark)

Jazlan, Ahmad; Sreeram, Victor; Shaker, Hamid Reza

2016-01-01

This paper presents the development of a new model reduction method for discrete-time bilinear systems based on the balanced truncation framework. In many model reduction applications, it is advantageous to analyze the characteristics of the system with emphasis on particular frequency intervals...... are the solution to a pair of new generalized Lyapunov equations. The conditions for solvability of these new generalized Lyapunov equations are derived and a numerical solution method for solving these generalized Lyapunov equations is presented. Numerical examples which illustrate the usage of the new...... generalized frequency interval controllability and observability gramians as part of the balanced truncation framework are provided to demonstrate the performance of the proposed method....

The influence of numerical models on determining the drag coefficient

Directory of Open Access Journals (Sweden)

Dobeš Josef

2014-03-01

Full Text Available The paper deals with numerical modelling of body aerodynamic drag coefficient in the transition from laminar to turbulent flow regimes, where the selection of a suitable numerical model is problematic. On the basic problem of flow around a simple body – sphere selected computational models are tested. The values obtained by numerical simulations of drag coefficients of each model are compared with the graph of dependency of the drag coefficient vs. Reynolds number for a sphere. Next the dependency of Strouhal number vs. Reynolds number is evaluated, where the vortex shedding frequency values for given speed are obtained numerically and experimentally and then the values are compared for each numerical model and experiment. The aim is to specify trends for the selection of appropriate numerical model for flow around bodies problem in which the precise description of the flow field around the obstacle is used to define the acoustic noise source. Numerical modelling is performed by finite volume method using CFD code.

Theory and numerics of gravitational waves from preheating after inflation

International Nuclear Information System (INIS)

Dufaux, Jean-Francois; Kofman, Lev; Bergman, Amanda; Felder, Gary; Uzan, Jean-Philippe

2007-01-01

Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast our method with other numerical methods in the literature, and then we apply it to preheating after chaotic inflation. In this case, we are able to check analytically our numerical results, which differ significantly from previous works. We discuss how the gravity-wave spectrum builds up with time and find that the amplitude and the frequency of its peak depend in a relatively simple way on the characteristic spatial scale amplified during preheating. We then estimate the peak frequency and amplitude of the spectrum produced in two models of preheating after hybrid inflation, which for some parameters may be relevant for gravity-wave interferometric experiments

Improved quantification of alite and belite in anhydrous Portland cements by 29Si MAS NMR: Effects of paramagnetic ions

DEFF Research Database (Denmark)

Poulsen, Søren Lundsted; Kocaba, Vanessa; Le Saoût, Gwenn

2009-01-01

The applicability, reliability, and repeatability of 29Si MAS NMR for determination of the quantities of alite (Ca3SiO5) and belite (Ca2SiO4) in anhydrous Portland cement was investigated in detail for 11 commercial Portland cements and the results compared with phase quantifications based...

Explicit frequency equations of free vibration of a nonlocal Timoshenko beam with surface effects

Science.gov (United States)

Zhao, Hai-Sheng; Zhang, Yao; Lie, Seng-Tjhen

2018-02-01

Considerations of nonlocal elasticity and surface effects in micro- and nanoscale beams are both important for the accurate prediction of natural frequency. In this study, the governing equation of a nonlocal Timoshenko beam with surface effects is established by taking into account three types of boundary conditions: hinged-hinged, clamped-clamped and clamped-hinged ends. For a hinged-hinged beam, an exact and explicit natural frequency equation is obtained. However, for clamped-clamped and clamped-hinged beams, the solutions of corresponding frequency equations must be determined numerically due to their transcendental nature. Hence, the Fredholm integral equation approach coupled with a curve fitting method is employed to derive the approximate fundamental frequency equations, which can predict the frequency values with high accuracy. In short, explicit frequency equations of the Timoshenko beam for three types of boundary conditions are proposed to exhibit directly the dependence of the natural frequency on the nonlocal elasticity, surface elasticity, residual surface stress, shear deformation and rotatory inertia, avoiding the complicated numerical computation.

Numerical and experimental study of actuator performance on piezoelectric microelectromechanical inkjet print head.

Science.gov (United States)

Van So, Pham; Jun, Hyun Woo; Lee, Jaichan

2013-12-01

We have investigated the actuator performance of a piezoelectrically actuated inkjet print head via the numerical and experimental analysis. The actuator consisting of multi-layer membranes, such as piezoelectric, elastic and other buffer layers, and ink chamber was fabricated by MEMS processing. The maximum displacement of the actuator membrane obtained in the experiment is explained by numerical analysis. A simulation of the actuator performance with fluidic damping shows that the resonant frequency of the membrane in liquid is reduced from its resonant frequency in air by a factor of three, which was also verified in the experiment. These simulation and experimental studies demonstrate how much "dynamic force," in terms of a membrane's maximum displacement, maximum force and driving frequency, can be produced by an actuator membrane interacting with fluid.

Modeling of Coaxial Slot Waveguides Using Analytical and Numerical Approaches: Revisited

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Kok Yeow You

2012-01-01

Full Text Available Our reviews of analytical methods and numerical methods for coaxial slot waveguides are presented. The theories, background, and physical principles related to frequency-domain electromagnetic equations for coaxial waveguides are reassessed. Comparisons of the accuracies of various types of admittance and impedance equations and numerical simulations are made, and the fringing field at the aperture sensor, which is represented by the lumped capacitance circuit, is evaluated. The accuracy and limitations of the analytical equations are explained in detail. The reasons for the replacement of analytical methods by numerical methods are outlined.

Time-domain modeling of electromagnetic diffusion with a frequency-domain code

NARCIS (Netherlands)

Mulder, W.A.; Wirianto, M.; Slob, E.C.

2007-01-01

We modeled time-domain EM measurements of induction currents for marine and land applications with a frequency-domain code. An analysis of the computational complexity of a number of numerical methods shows that frequency-domain modeling followed by a Fourier transform is an attractive choice if a

States' Participation Guidelines for Alternate Assessments Based on Modified Academic Achievement Standards (AA-MAS) in 2008. Synthesis Report 71

Science.gov (United States)

Lazarus, Sheryl S.; Rogers, Christopher; Cormier, Damien; Thurlow, Martha L.

2008-01-01

Federal regulations (U.S. Department of Education, 2007a) provide states with the flexibility to offer an alternate assessment based on modified academic achievement standards (AA-MAS). This assessment option is for a small group of students with disabilities who can make significant progress, but may not reach grade-level achievement within the…

Surface Characterization of Some Novel Bonded Phase Packing Materials for HPLC Columns Using MAS-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Jude Abia

2015-03-01

Full Text Available Information on the surface properties of three novel chemically bonded phase packing materials for High performance liquid chromatography (HPLC were obtained using spectra obtained by solid state cross-polarization (CP magic-angle spinning (MAS nuclear magnetic resonance (NMR spectroscopic experiments for the 29Si, and 13C nuclei. These packing materials were: Cogent bidentate C18 bonded to type-C silica, hybrid packing materials XTerra MS C18, and XBridge Prep. C18. The spectra obtained using cross-polarization magic angle spinning (CP-MAS on the Cogent bidentate C18 bonded to type-C silica show the surface to be densely populated with hydride groups (Si-H, with a relative surface coverage exceeding 80%. The hybrid packing materials XTerra and XBridge gave spectra that reveal the silicon atoms to be bonded to organic moieties embedded in the molecular structure of these materials with over 90% of the alkyl silicon atoms found within the completely condensed silicon environments. The hydrolytic stability of these materials were investigated in acidic aqueous solutions at pHs of 7.0 and 3.0, and it was found that while the samples of XTerra and XBridge were not affected by hydrolysis at this pH range, the sample of Cogent lost a significant proportion of its Si-H groups after five days of treatment in acidic aqueous solution.

TE/TM field solver for particle beam simulations without numerical Cherenkov radiation

Directory of Open Access Journals (Sweden)

Igor Zagorodnov

2005-04-01

Full Text Available The Yee finite-difference time domain method (FDTD is commonly used in wake field and particle-in-cell simulations. However, in accelerator modeling the high energy particles can travel in vacuum faster than their own radiation. This effect is commonly referred to as numerical Cherenkov radiation and is a consequence of numerical grid dispersion. Several numerical approaches are proposed to reduce the dispersion for all angles and for a given frequency range, that justifies itself for domains big in all three directions. On the contrary, in accelerator modeling the transverse dimensions and transverse beam velocity are small, but it is extremely important to eliminate the dispersion error in the well-defined direction of the beam motion for all frequencies. In this paper we propose a new two-level economical conservative scheme for electromagnetic field calculations in three dimensions. The scheme does not have dispersion in the longitudinal direction and is staircase-free (second order convergent. Unlike the FDTD method, it is based on a “transversal-electric/transversal-magnetic” (TE/TM-like splitting of the field components in time. The scheme assures energy and charge conservation. Additionally, the usage of damping terms allows suppressing high frequency noise generated due to the transverse dispersion and the current fluctuations. The dispersion relation of the damping scheme is analyzed. As numerical examples show, the new scheme is much more accurate on the long-time scale than the conventional FDTD approach.

Unidirectional ring-laser operation using sum-frequency mixing

DEFF Research Database (Denmark)

Tidemand-Lichtenberg, Peter; Cheng, Haynes Pak Hay; Pedersen, Christian

2010-01-01

A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss for the...... where lossless second-order nonlinear materials are available. Numerical modeling and experimental demonstration of parametric-induced unidirectional operation of a diode-pumped solid-state 1342 nm cw ring laser are presented.......A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss...

Piecewise Polynomial Aggregation as Preprocessing for Data Numerical Modeling

Science.gov (United States)

Dobronets, B. S.; Popova, O. A.

2018-05-01

Data aggregation issues for numerical modeling are reviewed in the present study. The authors discuss data aggregation procedures as preprocessing for subsequent numerical modeling. To calculate the data aggregation, the authors propose using numerical probabilistic analysis (NPA). An important feature of this study is how the authors represent the aggregated data. The study shows that the offered approach to data aggregation can be interpreted as the frequency distribution of a variable. To study its properties, the density function is used. For this purpose, the authors propose using the piecewise polynomial models. A suitable example of such approach is the spline. The authors show that their approach to data aggregation allows reducing the level of data uncertainty and significantly increasing the efficiency of numerical calculations. To demonstrate the degree of the correspondence of the proposed methods to reality, the authors developed a theoretical framework and considered numerical examples devoted to time series aggregation.

Frequency dependence of the pump-to-signal RIN transfer in fiber optical parametric amplifiers

DEFF Research Database (Denmark)

Pakarzadeh Dezfuli Nezhad, Hassan; Rottwitt, Karsten; Zakery, A.

2009-01-01

Using a numerical model, the frequency dependence of the pump-to-signal RIN transfer in FOPAs has been investigated. The model includes fiber loss, pump depletion as well as difference in group velocity among interacting beams.......Using a numerical model, the frequency dependence of the pump-to-signal RIN transfer in FOPAs has been investigated. The model includes fiber loss, pump depletion as well as difference in group velocity among interacting beams....

Nonspinning numerical relativity waveform surrogates: assessing the model

Science.gov (United States)

Field, Scott; Blackman, Jonathan; Galley, Chad; Scheel, Mark; Szilagyi, Bela; Tiglio, Manuel

2015-04-01

Recently, multi-modal gravitational waveform surrogate models have been built directly from data numerically generated by the Spectral Einstein Code (SpEC). I will describe ways in which the surrogate model error can be quantified. This task, in turn, requires (i) characterizing differences between waveforms computed by SpEC with those predicted by the surrogate model and (ii) estimating errors associated with the SpEC waveforms from which the surrogate is built. Both pieces can have numerous sources of numerical and systematic errors. We make an attempt to study the most dominant error sources and, ultimately, the surrogate model's fidelity. These investigations yield information about the surrogate model's uncertainty as a function of time (or frequency) and parameter, and could be useful in parameter estimation studies which seek to incorporate model error. Finally, I will conclude by comparing the numerical relativity surrogate model to other inspiral-merger-ringdown models. A companion talk will cover the building of multi-modal surrogate models.

Incorporating excitation-induced dephasing into the Maxwell-Bloch numerical modeling of photon echoes

International Nuclear Information System (INIS)

Burr, G.W.; Harris, Todd L.; Babbitt, Wm. Randall; Jefferson, C. Michael

2004-01-01

We describe the incorporation of excitation-induced dephasing (EID) into the Maxwell-Bloch numerical simulation of photon echoes. At each time step of the usual numerical integration, stochastic frequency jumps of ions--caused by excitation of neighboring ions--is modeled by convolving each Bloch vector with the Bloch vectors of nearby frequency detunings. The width of this convolution kernel follows the instantaneous change in overall population, integrated over the simulated bandwidth. This approach is validated by extensive comparison against published and original experimental results. The enhanced numerical model is then used to investigate the accuracy of experiments designed to extrapolate to the intrinsic dephasing time T 2 from data taken in the presence of EID. Such a modeling capability offers improved understanding of experimental results, and should allow quantitative analysis of engineering tradeoffs in realistic optical coherent transient applications

Computation of High-Frequency Waves with Random Uncertainty

KAUST Repository

Malenova, Gabriela; Motamed, Mohammad; Runborg, Olof; Tempone, Raul

2016-01-01

or nonlinear functionals of the wave solution and its spatial/temporal derivatives. The numerical scheme combines two techniques: a high-frequency method based on Gaussian beams [2, 3], a sparse stochastic collocation method [4]. The fast spectral

Experimental investigations and numerical simulations of methane cup-burner flame

Directory of Open Access Journals (Sweden)

Kubát P.

2013-04-01

Full Text Available Pulsation frequency of the cup-burner flame was determined by means of experimental investigations and numerical simulations. Simplified chemical kinetics was successfully implemented into a laminar fluid flow model applied to the complex burner geometry. Our methodical approach is based on the monitoring of flame emission, fast Fourier transformation and reproduction of measured spectral features by numerical simulations. Qualitative agreement between experimental and predicted oscillatory behaviour was obtained by employing a two-step methane oxidation scheme.

Numerical Investigation of Terahertz Emission Properties of Microring Difference-Frequency Resonators

DEFF Research Database (Denmark)

Iwaszczuk, Krzysztof; Bisgaard, Christer Zoffmann; Andronico, Alessio

2013-01-01

We investigate the electromagnetic design of whispering gallery mode (WGM) terahertz (THz) resonators. Terahertz radiation is generated by difference-frequency mixing of two electrically pumped high-order near-infrared laser WGM's at room temperature in the active cavity. Due to the leaky nature...... this symmetry by modification of the dielectric environment of the resonator, and demonstrate a fabrication-optimized structure based on a concentric grating design which efficiently couples the emitted radiation into a narrow, near-gaussian forward-propagating cone of well-defined linear or circular...

Internal oscillation frequencies and anharmonic effects for the double sine-Gordon kink

DEFF Research Database (Denmark)

Salerno, M.; Samuelsen, Mogens Rugholm

1989-01-01

A simple derivation of the small oscillation frequency around 4π-kink solutions of the double sine-Gordon equation is presented. Small corrections to these frequencies due to anharmonic effects are also numerically and analytically investigated. The analysis is based on energetic considerations...

Premises and Limitations in Defining and Measuring Synergy from M&As

Directory of Open Access Journals (Sweden)

Aevoae George Marian

2017-01-01

Full Text Available Mergers and acquisitions are performed worldwide mainly because of synergy. Although many invoke the term synergy as the key motivation of why they engage in M&As, research has led us to understand that it is not very clear in terms of what it actually is. In the scientific literature, synergy is mostly defined as being “2+2=5”. Thus, we first thought that it can only be a positive effect. But, latter on, we found out that synergy is not only positive, it can be negative as well, known as negative synergy or dyssynergy. The purpose of this paper is to shed some light on what is synergy, how can we quantify and classify it and why acquiring firms tend to pay more for the target firm. We believe that there is a link between the amount of premium paid for a target firm and the expectations for synergy.

Reply to Mas et al.: Comment on Gebhardt et al. MAD-MEX: Automatic Wall-to-Wall Land Cover Monitoring for the Mexican REDD-MRV Program Using All Landsat Data. Remote Sens. 2014, 6, 3923–3943

Directory of Open Access Journals (Sweden)

Michael Schmidt

2016-06-01

Full Text Available Mas, J.F. et al. have submitted a paper [1] for publication, which aims to respond to a paper published by Gebhardt et al. [2]. Mas, J.F. et al. had received a consultancy in 2013 to assess the quality of the early prototype products partly described in Gebhardt et al. in 2014. This consultancy, although a formal non-disclosure agreement had not been demanded, was awarded under the mutual understanding that the data handed over to Mas et al. constitute the early development phase of the program. Therefore, Mas et al. had been asked to give an assessment on the quality of the prototypes to obtain a proof of concept for the proposed workflow of MAD-Mex. It was clear that this assessment would suffer from limited availability of high quality training and validation data available in 2013. Mas et al. finally did not execute the consultancy due to the limited vector processing capacities in their lab. In October 2014, we sent the latest products, version 4.2 of the MAD-Mex products, including the more than 200,000 validation points gathered from independent expert interpreters of all Mexican ecosystems. Mas et al. did not respond to this transfer or to our request to collaborate in the quality control and assessment of MAD-Mex.

Evidence for radiation induced crosslinking in polytetrafluoroethylene by means of high-resolution solid-state 19F high-speed MAS NMR

International Nuclear Information System (INIS)

Katoh, Etsuko; Sugisawa, Hisashi; Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao; Yamazaki, Toshimasa

1999-01-01

Radiation effects on molecular structure of polytetrafluoroethylene (PTFE) were studied by high-resolution solid-state 19 F high speed magic angle spinning (HS MAS) NMR spectroscopy. Samples used for the NMR studies were prepared by electron beam irradiation of PTFE with a wide range of irradiation doses from 0.5-10 MGy in the molten state at 340 deg. C under oxygen-free atmosphere. While the non-irradiated PTFE displayed only an intense peak of the internal CF 2 , several new signals corresponding to CF 3 , CF 2 and CF groups were observed for the PTFE which was high temperature irradiated at 340 deg. C in oxygen-free atmosphere (hti-PTFE). Intensities of these new signals increased with an increase of irradiation dose. The present solid-state 19 F HS MAS NMR studies provide not only the first experimental evidence regarding the existence of crosslinking structure in hti-PTFE, directly detected as the CF signal, but also the crosslinking density which can be estimated from a proportion of the CF versus total fluorine signal intensities. The higher the irradiation dose, the higher the crosslinking density; hti-PTFE with 10 MGy contains one crosslinking site per approximately 24 CF 2 groups, while the hti-PTFE with 5 MGy contains one crosslinking site per approximately 36 CF 2 groups. Further, G value of crosslinking (G(x)) was estimated from the signal intensities of 19 F HS MAS NMR spectra. The highest G(x)-value, 1.85, was observed for the 2MGy hti-PTFE sample, suggesting that crosslinking of PTFE is formed most efficaciously with 2 MGy irradiation in the molten state at 340 deg. C under oxygen-free atmosphere

Numerical eduction of active multi-port data for in-duct obstructions

Science.gov (United States)

Sack, Stefan; Shur, Michael; Åbom, Mats; Strelets, Michael; Travin, Andrey

2017-12-01

A numerical method for aeroacoustic source characterization of in-duct components at frequencies beyond the cut-on frequencies of several acoustic modes is presented. Assuming linearity and time invariance, any ducted component can be fully characterized using a network (multi-port) model including source strength and scattering. A two-step multi-source approach is applied to numerical data in order to educe the multi-port characteristics. First, a scale resolving compressible flow simulation, here the Improved Delayed Detached Eddy Simulation (IDDES), is run to compute the channel flow that also contains the acoustic sources. Second, a linear acoustic computation, here the Linearized Navier Stokes Equations (LNSE), around a mean flow is solved for different acoustic loads to determine the component's scattering. The work uncovers the high potential of two-step numerical multi-port eduction methods. Particularly, it is shown that the acoustic source power spectra can be accurately extracted from IDDES data and the total acoustic power prediction is very good. Furthermore, a good result in the scattering data obtained from a second computationally inexpensive LNSE computation is achieved. The approach is interesting when describing mid-size duct systems, for example ventilation systems in aircraft and buildings, with a moderate number of higher order modes propagating in the considered frequency range. Therefore, the increasing availability of compressible flow data opens a wide field of applications.

The Influence of Sensor Size on Acoustic Emission Waveforms—A Numerical Study

Directory of Open Access Journals (Sweden)

Eleni Tsangouri

2018-01-01

Full Text Available The performance of Acoustic Emission technique is governed by the measuring efficiency of the piezoelectric sensors usually mounted on the structure surface. In the case of damage of bulk materials or plates, the sensors receive the acoustic waveforms of which the frequency and shape are correlated to the damage mode. This numerical study measures the waveforms received by point, medium and large size sensors and evaluates the effect of sensor size on the acoustic emission signals. Simulations are the only way to quantify the effect of sensor size ensuring that the frequency response of the different sensors is uniform. The cases of horizontal (on the same surface, vertical and diagonal excitation are numerically simulated, and the corresponding elastic wave displacement is measured for different sizes of sensors. It is shown that large size sensors significantly affect the wave magnitude and content in both time and frequency domains and especially in the case of surface wave excitation. The coherence between the original and received waveform is quantified and the numerical findings are experimentally supported. It is concluded that sensors with a size larger than half the size of the excitation wavelength start to seriously influence the accuracy of the AE waveform.

Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

Science.gov (United States)

Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

2015-09-01

In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

Infrared frequency-tunable coherent thermal sources

International Nuclear Information System (INIS)

Wang, Hao; Yang, Yue; Wang, Liping

2015-01-01

In this work, we numerically demonstrate an infrared (IR) frequency-tunable selective thermal emitter made of graphene-covered silicon carbide (SiC) gratings. Rigorous coupled-wave analysis shows temporally-coherent emission peaks associated with magnetic polariton (MP), whose resonance frequency can be dynamically tuned within the phonon absorption band of SiC by varying graphene chemical potential. An analytical inductor–capacitor circuit model is introduced to quantitatively predict the resonance frequency and further elucidate the mechanism for the tunable emission peak. The effects of grating geometric parameters, such as grating height, groove width and grating period, on the selective emission peak are explored. The direction-independent behavior of MP and associated coherent emission are also demonstrated. Moreover, by depositing four layers of graphene sheets onto the SiC gratings, a large tunability of 8.5% in peak frequency can be obtained to yield the coherent emission covering a broad frequency range from 820 to 890 cm −1 . The novel tunable metamaterial could pave the way to a new class of tunable thermal sources in the IR region. (paper)

Numerical study on increasing mass flow ratio by energy deposition of high frequency pulsed laser

International Nuclear Information System (INIS)

Wang Diankai; Hong Yanji; Li Qian

2013-01-01

The mass flow ratio (MFR) of air breathing ramjet inlet would be decreased, when the Mach number is lower than the designed value. High frequency pulsed laser energy was deposited upstream of the cowl lip to reflect the stream so as to increase the MFR. When the Mach number of the flow was 5.0, and the static pressure and temperature of the flow were 2 551.6 Pa and 116.7 K, respectively, two-dimensional non-stationary compressible RANS equations were solved with upwind format to study the mechanisms of increasing MFR by high frequency pulsed laser energy deposition. The laser deposition frequency was 100 kHz and the average power was 500 W. The crossing point of the first forebody oblique shock and extension line of cowl lip was selected as the expected point. Then the deposition position was optimized by searching near the expected point. The results indicate that with the optimization of laser energy deposition position, the MFR would be increased from 63% to 97%. The potential value of increasing MFR by high frequency pulsed laser energy deposition was proved. The method for selection of the energy deposition position was also presented. (authors)

Local environments and lithium adsorption on the iron oxyhydroxides lepidocrocite (gamma-FeOOH) and goethite (alpha-FeOOH): A ²H-2 and ⁷Li solid-state MAS NMR study

DEFF Research Database (Denmark)

Nielsen, Ulla Gro; Grey, Clare P.; Paik, Jonkim

2008-01-01

2H and 7LiMAS NMR spectroscopy techniques were applied to study the local surface and bulk environments of iron oxyhydroxide lepiclocrocite (gamma-FeOOH). 2H variable-temperature (VT) MAS NMR experiments were performed, showing the presence of short-range, strong antiferromagnetic correlations......, even at temperatures above the Neel temperature, TN, 77 K. The formation of a Li+ inner-sphere complex on the surface of lepiclocrocite was confirmed by the observation of a signal with a large 7Li hyperfine shift in the 7Li  MAS NMR spectrum. The effect of pH and relative humidity (RH...

Femtosecond frequency comb based distance measurement in air

NARCIS (Netherlands)

Balling, P.; Kren, P.; Masika, P.; van den Berg, S.A.

2009-01-01

Interferometric measurement of distance using a femtosecond frequency comb is demonstrated and compared with a counting interferometer displacement measurement. A numerical model of pulse propagation in air is developed and the results are compared with experimental data for short distances. The

Spectral element method for elastic and acoustic waves in frequency domain

Energy Technology Data Exchange (ETDEWEB)

Shi, Linlin; Zhou, Yuanguo; Wang, Jia-Min; Zhuang, Mingwei [Institute of Electromagnetics and Acoustics, and Department of Electronic Science, Xiamen, 361005 (China); Liu, Na, E-mail: liuna@xmu.edu.cn [Institute of Electromagnetics and Acoustics, and Department of Electronic Science, Xiamen, 361005 (China); Liu, Qing Huo, E-mail: qhliu@duke.edu [Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708 (United States)

2016-12-15

Numerical techniques in time domain are widespread in seismic and acoustic modeling. In some applications, however, frequency-domain techniques can be advantageous over the time-domain approach when narrow band results are desired, especially if multiple sources can be handled more conveniently in the frequency domain. Moreover, the medium attenuation effects can be more accurately and conveniently modeled in the frequency domain. In this paper, we present a spectral-element method (SEM) in frequency domain to simulate elastic and acoustic waves in anisotropic, heterogeneous, and lossy media. The SEM is based upon the finite-element framework and has exponential convergence because of the use of GLL basis functions. The anisotropic perfectly matched layer is employed to truncate the boundary for unbounded problems. Compared with the conventional finite-element method, the number of unknowns in the SEM is significantly reduced, and higher order accuracy is obtained due to its spectral accuracy. To account for the acoustic-solid interaction, the domain decomposition method (DDM) based upon the discontinuous Galerkin spectral-element method is proposed. Numerical experiments show the proposed method can be an efficient alternative for accurate calculation of elastic and acoustic waves in frequency domain.

Marrero Regalado y Aguiar: El arte masónico oficial de la Postguerra en Canarias

Directory of Open Access Journals (Sweden)

David Martín López

2008-12-01

Full Text Available La masonería, como institución filantrópica y bien asentada durante la II República en España, fue totalmente rechazada por Franco desde su Alzamiento de 1936. Sin embargo, la protección oficial de la masonería en Canarias hizo que artistas masones como José Aguiar o como el arquitecto Marrero Regalado pudieran materializar su estética en numerosos proyectos para un nuevo Estado, en el que la concepción masónica del Ser Humano aparece como lenguaje encubierto y subversivo.

Frequency comb generation in a continuously pumped optical parametric oscillator

Science.gov (United States)

Mosca, S.; Parisi, M.; Ricciardi, I.; Leo, F.; Hansson, T.; Erkintalo, M.; Maddaloni, P.; De Natale, P.; Wabnitz, S.; De Rosa, M.

2018-02-01

We demonstrate optical frequency comb generation in a continuously pumped optical parametric oscillator, in the parametric region around half of the pump frequency. We also model the dynamics of such quadratic combs using a single time-domain mean-field equation, and obtain simulation results that are in good agreement with experimentally observed spectra. Moreover, we numerically investigate the coherence properties of simulated combs, showing the existence of correlated and phase-locked combs. Our work could pave the way for a new class of frequency comb sources, which may enable straightforward access to new spectral regions and stimulate novel applications of frequency combs.

Effect of section shape on frequencies of natural oscillations of tubular springs

Science.gov (United States)

Pirogov, S. P.; Chuba, A. Yu; Cherentsov, D. A.

2018-05-01

The necessity of determining the frequencies of natural oscillations of manometric tubular springs is substantiated. Based on the mathematical model and computer program, numerical experiments were performed that allowed us to reveal the effect of geometric parameters on the frequencies of free oscillations of manometric tubular springs.

HYPOCENTER DISTRIBUTION OF LOW FREQUENCY EVENT AT PAPANDAYAN VOLCANO

Directory of Open Access Journals (Sweden)

Muhammad Mifta Hasan

2016-10-01

Full Text Available Papandayan volcano is a stratovolcano with irregular cone-shaped has eight craters around the peak. The most active crater in Papandayan is a Mas crater. Distribution of relocated event calculated using Geiger Adaptive Damping Algorithm (GAD shows that the epicenter of the event centered below Mas crater with maximum rms 0.114. While depth of the hypocenter range between 0-2 km and 5-6 km due to activity of steam and gas.

High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures

International Nuclear Information System (INIS)

Kapaev, V. V.; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N.

2013-01-01

The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schrödinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In 0.53 Ga 0.47 As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V dc in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

Numerical study of pressure fluctuations transfer law in different flow rate of turbine mode in a prototype pump turbine

International Nuclear Information System (INIS)

Sun, Y K; Zuo, Z G; Liu, S H; Wu, Y L; Liu, J T; Qin, D Q; Wei, X Z

2013-01-01

Numerical simulation using SST k-w turbulence model was carried out, to predict pressure fluctuation transfer law in turbine mode. Three operating points with different mass flow rates are simulated. The results of numerical simulation show that, the amplitude and frequency of pressure fluctuations in different positions are very different. The transfer law of amplitude and frequency of pressure fluctuations change with different position and different mass flow rate. Blade passing frequency (BPF) is the first dominant frequency in vaneless space, while component in this frequency got smaller in the upstream and downstream of vaneless space when the mass flow is set. Furthermore triple blade passing frequency (3BPF) component obtained a different transfer law through the whole flow passage. The amplitude and frequency of pressure fluctuations is also different in different circumference position of vaneless space. When the mass flow is different, the distribution of pressure fluctuations in circumference is different. The frequency component of pressure fluctuations in all the positions is different too

Numerical Modelling of the Czochralski Growth of β-Ga2O3

Directory of Open Access Journals (Sweden)

Wolfram Miller

2017-01-01

Full Text Available Our numerical modelling of the Czochralski growth of single crystalline β-Ga 2 O 3 crystals (monoclinic symmetry starts at the 2D heat transport analysis within the crystal growth furnace, proceeds with the 3D heat transport and fluid flow analysis in the crystal-melt-crucible arrangement and targets the 3D thermal stress analysis within the β-Ga 2 O 3 crystal. In order to perform the stress analysis, we measured the thermal expansion coefficients and the elastic stiffness coefficients in two samples of a β-Ga 2 O 3 crystal grown at IKZ. Additionally, we analyse published data of β-Ga 2 O 3 material properties and use data from literature for comparative calculations. The computations were performed by the software packages CrysMAS, CGsim, Ansys-cfx and comsol Multiphysics. By the hand of two different thermal expansion data sets and two different crystal orientations, we analyse the elastic stresses in terms of the von-Mises stress.

"KinLeaves" reklāmas aktivitātes sociālajā tīklā “Facebook” 2016. gadā

OpenAIRE

Mandrika, Dana

2017-01-01

Bakalaura darba mērķis ir izpētīt, kādas reklāmas aktivitātes uzņēmums ir veicis un noskaidrot, vai sociālajā tīklā “Facebook” ar reklāmas aktivitātēm ir iespējams sasniegt mērķauditoriju. Darbs sastāv no trīs daļām – teorētiskās, metodoloģiskās un empīriskās. Teorētisko daļu veido nodaļas par reklāmu, sociālo tīklu vietnēm, sociālo tīklu „Facebook” un reklāmu sociālo tīklu vietnēs. Metodoloģiskajā daļā apskatītas pētījumā izmantotās metodes - kontentanalīze, intervija, anketēšana. Empīrisk...

Lima masónica: las logias simbólicas y su progreso en el medio urbano a fines del siglo XIX

Directory of Open Access Journals (Sweden)

Chocano, Magdalena

2010-08-01

Full Text Available This article deals with the organization of the Grand Lodge of Peru, founded in 1882. Using Masonic publications and sources, it aims to establish the dynamics of its local lodges and to assess the character of Masonic activity in Peru at the end of the 19^th century. Finally, it examines the political positioning of the Masonic leadership and its performance in the national political scene where it challenged Catholic exclusivity.

Este artículo presenta un análisis de la organización de la Gran Logia del Perú, fundada en 1882. A partir de las fuentes masónicas, se busca establecer la dinámica de cada logia y el carácter del accionar masónico. Finalmente, se examinan las actitudes políticas que fomentaron sus dirigentes y su actuación en la escena nacional donde desafiaron al exclusivismo católico.

Numerical investigation on vibration and noise induced by unsteady flow in an axial-flow pump

Energy Technology Data Exchange (ETDEWEB)

Chen, Eryun; Ma, Zui Ling; Yang, Ai Ling; Nan, Guo Fang [School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai (China); Zhao, Gai Ping [School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai (China); Li, Guo Ping [Shanghai Marine Equipment Research Institute, Shanghai (China)

2016-12-15

Full-scale structural vibration and noise induced by flow in an axial-flow pump was simulated by a hybrid numerical method. An unsteady flow field was solved by a large eddy simulation-based computational fluid dynamics commercial code, Fluent. An experimental validation on pressure fluctuations was performed to impose an appropriate vibration exciting source. The consistency between the computed results and experimental tests were interesting. The modes of the axial-flow pump were computed by the finite element method. After that, the pump vibration and sound field were solved using a coupled vibro-acoustic model. The numerical results indicated that the the blade-passing frequency was the dominant frequency of the vibration acceleration of the pump. This result was consistent with frequency spectral characteristics of unsteady pressure fluctuation. Finally, comparisons of the vibration acceleration between the computed results and the experimental test were conducted. These comparisons validated the computed results. This study shows that using the hybrid numerical method to evaluate the flow-induced vibration and noise generated in an axial-flow pump is feasible.

Numerical analysis of the flow field in a sloshing tank with a horizontal perforated plate

Science.gov (United States)

Jin, Heng; Liu, Yong; Li, Huajun; Fu, Qiang

2017-08-01

Liquid sloshing is a type of free surface flow inside a partially filled water tank. Sloshing exerts a significant effect on the safety of liquid transport systems; in particular, it may cause large hydrodynamic loads when the frequency of the tank motion is close to the natural frequency of the tank. Perforated plates have recently been used to suppress the violent movement of liquids in a sloshing tank at resonant conditions. In this study, a numerical model based on OpenFOAM (Open Source Field Operation and Manipulation), an open source computed fluid dynamic code, is used to investigate resonant sloshing in a swaying tank with a submerged horizontal perforated plate. The numerical results of the free surface elevations are first verified using experimental data, and then the flow characteristics around the perforated plate and the fluid velocity distribution in the entire tank are examined using numerical examples. The results clearly show differences in sloshing motions under first-order and third-order resonant frequencies. This study provides a better understanding of the energy dissipation mechanism of a horizontal perforated plate in a swaying tank.

Numerical model updating technique for structures using firefly algorithm

Science.gov (United States)

Sai Kubair, K.; Mohan, S. C.

2018-03-01

Numerical model updating is a technique used for updating the existing experimental models for any structures related to civil, mechanical, automobiles, marine, aerospace engineering, etc. The basic concept behind this technique is updating the numerical models to closely match with experimental data obtained from real or prototype test structures. The present work involves the development of numerical model using MATLAB as a computational tool and with mathematical equations that define the experimental model. Firefly algorithm is used as an optimization tool in this study. In this updating process a response parameter of the structure has to be chosen, which helps to correlate the numerical model developed with the experimental results obtained. The variables for the updating can be either material or geometrical properties of the model or both. In this study, to verify the proposed technique, a cantilever beam is analyzed for its tip deflection and a space frame has been analyzed for its natural frequencies. Both the models are updated with their respective response values obtained from experimental results. The numerical results after updating show that there is a close relationship that can be brought between the experimental and the numerical models.

Computation of High-Frequency Waves with Random Uncertainty

KAUST Repository

Malenova, Gabriela

2016-01-06

We consider the forward propagation of uncertainty in high-frequency waves, described by the second order wave equation with highly oscillatory initial data. The main sources of uncertainty are the wave speed and/or the initial phase and amplitude, described by a finite number of random variables with known joint probability distribution. We propose a stochastic spectral asymptotic method [1] for computing the statistics of uncertain output quantities of interest (QoIs), which are often linear or nonlinear functionals of the wave solution and its spatial/temporal derivatives. The numerical scheme combines two techniques: a high-frequency method based on Gaussian beams [2, 3], a sparse stochastic collocation method [4]. The fast spectral convergence of the proposed method depends crucially on the presence of high stochastic regularity of the QoI independent of the wave frequency. In general, the high-frequency wave solutions to parametric hyperbolic equations are highly oscillatory and non-smooth in both physical and stochastic spaces. Consequently, the stochastic regularity of the QoI, which is a functional of the wave solution, may in principle below and depend on frequency. In the present work, we provide theoretical arguments and numerical evidence that physically motivated QoIs based on local averages of |uE|2 are smooth, with derivatives in the stochastic space uniformly bounded in E, where uE and E denote the highly oscillatory wave solution and the short wavelength, respectively. This observable related regularity makes the proposed approach more efficient than current asymptotic approaches based on Monte Carlo sampling techniques.

Remote Sensing of Radiative and Microphysical Properties of Clouds During TC (sup 4): Results from MAS, MASTER, MODIS, and MISR

Science.gov (United States)

King, Michael D.; Platnick, Steven; Wind, Galina; Arnold, G. Thomas; Dominguez, Roseanne T.

2010-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator (MAS) and MODIS/Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Airborne Simulator (MASTER) were used to obtain measurements of the bidirectional reflectance and brightness temperature of clouds at 50 discrete wavelengths between 0.47 and 14.2 microns (12.9 microns for MASTER). These observations were obtained from the NASA ER-2 aircraft as part of the Tropical Composition, Cloud and Climate Coupling (TC4) experiment conducted over Central America and surrounding Pacific and Atlantic Oceans between 17 July and 8 August 2007. Multispectral images in eleven distinct bands were used to derive a confidence in clear sky (or alternatively the probability Of cloud) over land and ocean ecosystems. Based on the results of individual tests run as part of the cloud mask, an algorithm was developed to estimate the phase of the clouds (liquid water, ice, or undetermined phase). The cloud optical thickness and effective radius were derived for both liquid water and ice clouds that were detected during each flight, using a nearly identical algorithm to that implemented operationally to process MODIS Cloud data from the Aqua and Terra satellites (Collection 5). This analysis shows that the cloud mask developed for operational use on MODIS, and tested using MAS and MASTER data in TC(sup 4), is quite capable of distinguishing both liquid water and ice clouds during daytime conditions over both land and ocean. The cloud optical thickness and effective radius retrievals use five distinct bands of the MAS (or MASTER), and these results were compared with nearly simultaneous retrievals of marine liquid water clouds from MODIS on the Terra spacecraft. Finally, this MODIS-based algorithm was adapted to Multiangle Imaging SpectroRadiometer (MISR) data to infer the cloud optical thickness Of liquid water clouds from MISR. Results of this analysis are compared and contrasted.

QuBiLS-MAS, open source multi-platform software for atom- and bond-based topological (2D) and chiral (2.5D) algebraic molecular descriptors computations.

Science.gov (United States)

Valdés-Martiní, José R; Marrero-Ponce, Yovani; García-Jacas, César R; Martinez-Mayorga, Karina; Barigye, Stephen J; Vaz d'Almeida, Yasser Silveira; Pham-The, Hai; Pérez-Giménez, Facundo; Morell, Carlos A

2017-06-07

In previous reports, Marrero-Ponce et al. proposed algebraic formalisms for characterizing topological (2D) and chiral (2.5D) molecular features through atom- and bond-based ToMoCoMD-CARDD (acronym for Topological Molecular Computational Design-Computer Aided Rational Drug Design) molecular descriptors. These MDs codify molecular information based on the bilinear, quadratic and linear algebraic forms and the graph-theoretical electronic-density and edge-adjacency matrices in order to consider atom- and bond-based relations, respectively. These MDs have been successfully applied in the screening of chemical compounds of different therapeutic applications ranging from antimalarials, antibacterials, tyrosinase inhibitors and so on. To compute these MDs, a computational program with the same name was initially developed. However, this in house software barely offered the functionalities required in contemporary molecular modeling tasks, in addition to the inherent limitations that made its usability impractical. Therefore, the present manuscript introduces the QuBiLS-MAS (acronym for Quadratic, Bilinear and N-Linear mapS based on graph-theoretic electronic-density Matrices and Atomic weightingS) software designed to compute topological (0-2.5D) molecular descriptors based on bilinear, quadratic and linear algebraic forms for atom- and bond-based relations. The QuBiLS-MAS module was designed as standalone software, in which extensions and generalizations of the former ToMoCoMD-CARDD 2D-algebraic indices are implemented, considering the following aspects: (a) two new matrix normalization approaches based on double-stochastic and mutual probability formalisms; (b) topological constraints (cut-offs) to take into account particular inter-atomic relations; (c) six additional atomic properties to be used as weighting schemes in the calculation of the molecular vectors; (d) four new local-fragments to consider molecular regions of interest; (e) number of lone-pair electrons in

Frequency Doubling Broadband Light in Multiple Crystals

International Nuclear Information System (INIS)

Alford, William J.; Smith, Arlee V.

2000-01-01

The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth

High frequency electromagnetic processes in induction motors supplied from PWM inverters

Directory of Open Access Journals (Sweden)

Ioan Ţilea

2010-12-01

Full Text Available The paper presents the electromagnetic interference between induction motors and inverters when at high frequency electromagnetic process appears in induction motors having a parallel resonant effect because of parasitic capacitive coupling between windings and ground, using a numerical model in simulink and a high frequency induction motor equivalent circuit model this effect is shown.

Numerical simulation of the sustaining discharge in radio frequency hollow cathode discharge in argon

Energy Technology Data Exchange (ETDEWEB)

Jiang, Xin-Xian; He, Feng, E-mail: hefeng@bit.edu.cn; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Chen, Qiang, E-mail: lppmchenqiang@hotmail.com; Ge, Teng [Laboratory of Plasma Physics and Materials, Beijing Institute of Graphic Communication, Beijing 10081 (China)

2014-03-15

In this paper, a two-dimensional fluid model was developed to study the radio frequency (RF) hollow cathode discharge (HCD) in argon at 1 Torr. The evolutions of the particle density distribution and the ionization rate distribution in RF HCD at 13.56 MHz indicate that the discharge mainly occurs inside the hollow cathode. The spatio-temporal distributions of the ionization rate and the power deposition within the hollow cathode imply that sheath oscillation heating is the primary mechanism to sustain the RF HCD, whereas secondary electron emission plays a negligible role. However, as driving frequency decreases, secondary electron heating becomes a dominant mechanism to sustain the discharge in RF hollow cathode.

Numerical calculation of high frequency fast wave current drive in a reactor grade tokamak

International Nuclear Information System (INIS)

Ushigusa, Kenkichi; Hamamatsu, Kiyotaka

1988-02-01

A fast wave current drive with a high frequency is estimated for a reactor grade tokamak by the ray tracing and the quasi-linear Fokker-Planck calculations with an assumption of single path absorption. The fast wave can drive RF current with the drive efficiency of η CD = n-bar e (10 19 m -3 )I RC (A)R(m)/P RF (W) ∼ 3.0 when the wave frequency is selected to be f/f ci > 7. A sharp wave spectrum and a ph|| >/υ Te ∼ 3.0 are required to obtain a good efficiency. A center peaked RF current profile can be formed with an appropriate wave spectrum even in the high temperature plasma. (author)

Analytical and Numerical Studies of Sloshing in Tanks

Energy Technology Data Exchange (ETDEWEB)

Solaas, F

1996-12-31

For oil cargo ship tanks and liquid natural gas carriers, the dimensions of the tanks are often such that the highest resonant sloshing periods and the ship motions are in the same period range, which may cause violent resonant sloshing of the liquid. In this doctoral thesis, linear and non-linear analytical potential theory solutions of the sloshing problem are studied for a two-dimensional rectangular tank and a vertical circular cylindrical tank, using perturbation technique for the non-linear case. The tank is forced to oscillate harmonically with small amplitudes of sway with frequency in the vicinity of the lowest natural frequency of the fluid inside the tank. The method is extended to other tank shapes using a combined analytical and numerical method. A boundary element numerical method is used to determine the eigenfunctions and eigenvalues of the problem. These are used in the non-linear analytical free surface conditions, and the velocity potential and free surface elevation for each boundary value problem in the perturbation scheme are determined by the boundary element method. Both the analytical method and the combined analytical and numerical method are restricted to tanks with vertical walls in the free surface. The suitability of a commercial programme, FLOW-3D, to estimate sloshing is studied. It solves the Navier-Stokes equations by the finite difference method. The free surface as function of time is traced using the fractional volume of fluid method. 59 refs., 54 figs., 37 tabs.

Analytical and Numerical Studies of Sloshing in Tanks

Energy Technology Data Exchange (ETDEWEB)

Solaas, F.

1995-12-31

For oil cargo ship tanks and liquid natural gas carriers, the dimensions of the tanks are often such that the highest resonant sloshing periods and the ship motions are in the same period range, which may cause violent resonant sloshing of the liquid. In this doctoral thesis, linear and non-linear analytical potential theory solutions of the sloshing problem are studied for a two-dimensional rectangular tank and a vertical circular cylindrical tank, using perturbation technique for the non-linear case. The tank is forced to oscillate harmonically with small amplitudes of sway with frequency in the vicinity of the lowest natural frequency of the fluid inside the tank. The method is extended to other tank shapes using a combined analytical and numerical method. A boundary element numerical method is used to determine the eigenfunctions and eigenvalues of the problem. These are used in the non-linear analytical free surface conditions, and the velocity potential and free surface elevation for each boundary value problem in the perturbation scheme are determined by the boundary element method. Both the analytical method and the combined analytical and numerical method are restricted to tanks with vertical walls in the free surface. The suitability of a commercial programme, FLOW-3D, to estimate sloshing is studied. It solves the Navier-Stokes equations by the finite difference method. The free surface as function of time is traced using the fractional volume of fluid method. 59 refs., 54 figs., 37 tabs.

Numerical modelling of the HAB Energy Buoy: Stage 1

DEFF Research Database (Denmark)

Kurniawan, Adi

This report presents the results of the first stage of the project "Numerical modelling of the HAB Energy Buoy". The objectives of this stage are to develop a numerical model of the HAB Energy Buoy, a self-reacting wave energy device consisting of two heaving bodies, and to investigate a number...... and a summary of the main findings is presented. A numerical model of the HAB Energy Buoy has been developed in the frequency domain using two alternative formulations of the equations of motion. The model is capable of predicting the power capture, motion response, and power take-off loads of the device...... configuration are imposed to give a more realistic prediction of the power capture and help ensure a fair comparison. Recommendations with regard to the HAB design are finally suggested....

Onset of chaos and dc current-voltage characteristics of rf-driven Josephson junctions in the low-frequency regime

International Nuclear Information System (INIS)

Chi, C.C.; Vanneste, C.

1990-01-01

A comprehensive picture of the dc current-voltage (I-V) characteristics of rf-driven Josephson junctions in the low-frequency regime is presented. The boundary of the low-frequency regime is roughly defined by the junction characteristic frequency for overdamped junctions, and by the inverse of the junction damping time for underdamped junctions. An adiabatic model valid for the low-frequency regime is used to describe the overall shapes of the I-V curves, which is in good agreement with both the numerical simulations and the experimental results. For underdamped junctions, the Shapiro steps are the prominent features on the I-V curves if the rf frequency is sufficiently below the boundary. As the rf frequency is increased towards the boundary, large negatively-going tails on top of the Shapiro steps are observed both experimentally and numerically. Numerical simulations using the resistively- and capacitively-shunted-junction model (RCSJ model) reveal that the negatively-going tail is a signature of the low-frequency boundary of the junction chaotic regime. With use of the adiabatic model and the existence of plasma oscillations for underdamped junctions, the onset of chaos and its effect on the Shapiro steps can be fully explained. The high-frequency limit of the adiabatic model and the chaotic behavior of the Josephson junctions beyond the low-frequency regime are also briefly discussed

UJI APLIKASI VAKSIN HYDROVAC UNTUK PENCEGAHAN PENYAKIT MERAH PADA IKAN MAS (Cyprinus carpio DAN GURAME (Osphronemus gouramy DI BALAI BENIH IKAN PANDAK KABUPATEN BANYUMAS

Directory of Open Access Journals (Sweden)

Indrawati Indrawati

2009-06-01

Full Text Available Uji aplikasi vaksin ini bertujuan untuk mengetahui pengaruh pemberian vaksin hydrovac terhadap perkembangan kesehatan ikan mas dan gurami, serta mendapatkan informasi tentang cara pengendalian, melalui tindakan pencegahan ikan air tawar yang terserang wabah penyakit Aeromonas hydrophila. Sebanyak 39 ekor ikan mas (Cyprinus carpio dengan bobot rata-rata 1 kg dan panjang rata-rata 30 cm dan108 ekor ikan gurami (Osphronemus gouramy L. dengan bobot rata-rata 250 g dan panjang rata-rata 10 cm yang berasal dari Balai Benih Ikan (BBI Pandak Kabupaten Banyumas, digunakan sebagai ikan uji. Vaksin yang digunakan adalah “vaksin hydrovac” yang diproduksi oleh Laboratorium Patologi Ikan. Balai Riset Perikanan Budidaya Air Tawar, Bogor. Vaksin diaplikasikan dengan cara dicampur pelet dengan dosis 2--3 mL per kilogram bobot badan ikan yang diberikan selama 5--7 hari berturut-turut dan setelah satu bulan kemudian dilakukan vaksinasi ulangan (booster terhadap ikan yang telah divaksin dengan cara yang sama. Hasil uji menunjukkan bahwa ikan baik ikan mas maupun gurame yang divaksin menunjukkan angka sintasan yang cukup tinggi apabila dibandingkan dengan ikan yang tidak divaksin. Mortalitas ikan uji yang tidak divaksin terjadi mulai minggu ke-5 dan ke-6.

Multi-frequency acoustic metasurface for extraordinary reflection and sound focusing

Directory of Open Access Journals (Sweden)

Yi-Fan Zhu

2016-12-01

Full Text Available We theoretically and numerically present the design of multi-frequency acoustic metasurfaces (MFAMs with simple structure that can work not only at fundamental frequency, but also at their harmonic frequencies, which breaks the single frequency limitation in conventional resonance-based acoustic metasurfaces. The phase matched condition for achromatic manipulation is discussed. We demonstrate achromatic extraordinary reflection and sound focusing at 1700Hz, 3400Hz, and 5100Hz, that is, they have the same reflection direction and the same focusing position. This significant feature may pave the way to new type of acoustic metasurface, and will also extend acoustic metasurface applications to strongly nonlinear source cases.

Characterization of coal structure by CP/MAS carbon-13 NMR spectrometry

International Nuclear Information System (INIS)

Yoshida, T.; Maekawa, Y.

1987-01-01

Cross-polarization (CP)/magic angle spinning (MAS) carbon-13 nuclear magnetic resonance (n.m.r.) spectrometry has been applied to the analysis of the whole structures of different ranks of coal. Three basic structural parameters, namely carbon aromaticity fa, new carbon aromaticity fa', and atomic H/C ratio for the hypothetical unsubstituted aromatic nuclei Haru/Car, were derived from the combined data of ultimate analysis, the distributions of carbon and oxygen functional groups obtained from the spectrum and the distribution of four types of methylene carbon groups in coal. Both fa and fa' values generally increased with coal rank and ranged from 0.51 to 0.71 and from 0.62 to 0.76, respectively. Haru/Car value tended to decrease with coal rank although the value was greatly affected by the types of hydroaromatic methylene carbons to aromatic rings. The values indicated that lower-rank coals consisted mainly of 1-3 aromatic rings, and higher-rank coals, 3-5 aromatic rings. 24 refs.; 5 figs.; 4 tabs

Orthogonal Multi-Carrier DS-CDMA with Frequency-Domain Equalization

Science.gov (United States)

Tanaka, Ken; Tomeba, Hiromichi; Adachi, Fumiyuki

Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of orthogonal frequency division multiplexing (OFDM) and time-domain spreading, while multi-carrier code division multiple access (MC-CDMA) is a combination of OFDM and frequency-domain spreading. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equalization (FDE), since the frequency diversity gain is obtained. On the other hand, the conventional orthogonal MC DS-CDMA fails to achieve any frequency diversity gain. In this paper, we propose a new orthogonal MC DS-CDMA that can obtain the frequency diversity gain by applying FDE. The conditional BER analysis is presented. The theoretical average BER performance in a frequency-selective Rayleigh fading channel is evaluated by the Monte-Carlo numerical computation method using the derived conditional BER and is confirmed by computer simulation of the orthogonal MC DS-CDMA signal transmission.

Suppression of nonlinear frequency-sweeping of resonant interchange modes in a magnetic dipole with applied radio frequency fields

International Nuclear Information System (INIS)

Maslovsky, D.; Levitt, B.; Mauel, M. E.

2003-01-01

Interchange instabilities excited by energetic electrons trapped by a magnetic dipole nonlinearly saturate and exhibit complex, coherent spectral characteristics and frequency sweeping [H. P. Warren and M. E. Mauel, Phys. Plasmas 2, 4185 (1995)]. When monochromatic radio frequency (rf) fields are applied in the range of 100-1000 MHz, the saturation behavior of the interchange instability changes dramatically. For applied fields of sufficient intensity and pulse-length, coherent interchange fluctuations are suppressed and frequency sweeping is eliminated. When rf fields are switched off, coherent frequency sweeping reappears. Since low frequency interchange instabilities preserve the electron's first and second adiabatic invariants, these observations can be interpreted as resulting from nonlinear resonant wave-particle interactions described within a particle phase-space, (ψ,φ), comprised of the third adiabatic invariant and the azimuthal angle. Self-consistent numerical simulation is used to study (1) the nonlinear development of the instability, (2) the radial mode structure of the interchange instability, and (3) the suppression of frequency sweeping. When the applied rf heating is modeled as an 'rf collisionality', the simulation reproduces frequency sweeping suppression and suggests an explanation for the observations that is consistent with Berk and co-workers [H. L. Berk et al., Phys. Plasmas 6, 3102 (1999)

A novel differential frequency micro-gyroscope

KAUST Repository

Nayfeh, A. H.

2013-07-10

We present a frequency-domain method to measure angular speeds using electrostatic micro-electro-mechanical system actuators. Towards this end, we study a single-axis gyroscope made of a micro-cantilever and a proof-mass coupled to two fixed electrodes. The gyroscope possesses two orthogonal axes of symmetry and identical flexural mode shapes along these axes. We develop the equations of motion describing the coupled bending modes in the presence of electrostatic and Coriolis forces. Furthermore, we derive a consistent closed-form higher-order expression for the natural frequencies of the coupled flexural modes. The closed-form expression is verified by comparing its results to those obtained from numerical integration of the equations of motion. We find that rotations around the beam axis couple each pair of identical bending modes to produce a pair of global modes. They also split their common natural frequency into a pair of closely spaced natural frequencies. We propose the use of the difference between this pair of frequencies, which is linearly proportional to the speed of rotation around the beam axis, as a detector for the angular speed.

Digital radiography: optimization of image quality and dose using multi-frequency software.

Science.gov (United States)

Precht, H; Gerke, O; Rosendahl, K; Tingberg, A; Waaler, D

2012-09-01

New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

Numerical counting ratemeter with variable time constant and integrated circuits

International Nuclear Information System (INIS)

Kaiser, J.; Fuan, J.

1967-01-01

We present here the prototype of a numerical counting ratemeter which is a special version of variable time-constant frequency meter (1). The originality of this work lies in the fact that the change in the time constant is carried out automatically. Since the criterion for this change is the accuracy in the annunciated result, the integration time is varied as a function of the frequency. For the prototype described in this report, the time constant varies from 1 sec to 1 millisec. for frequencies in the range 10 Hz to 10 MHz. This prototype is built entirely of MECL-type integrated circuits from Motorola and is thus contained in two relatively small boxes. (authors) [fr

Application of high Tc superconductors as frequency selective surfaces: Experiment and theory

International Nuclear Information System (INIS)

Dawei Zhang; Yahya Rahmat-Samii; Fetterman, H.R.

1993-01-01

YBa 2 Cu 3 O 7-x and Tl 2 CaBa 2 Cu 2 O 8 high temperature superconducting thin films were utilized to fabricate frequency selective surfaces (FSS) at millimeter-wave frequencies (75--110 GHz). An analytical/numerical model was applied, using a Floquet expansion and the Method of Moments, to analyze bandstop superconducting frequency selective surfaces. Experimental results were compared with the model, and showed a good agreement with resonant frequency prediction with an accuracy of better than 1%. The use of the superconducting frequency selective surfaces as quasi-optical millimeter-wave bandpass filters was also demonstrated

Arnol'd tongues for a resonant injection-locked frequency divider: analytical and numerical results

DEFF Research Database (Denmark)

Bartuccelli, Michele; Deane, Jonathan H.B.; Gentile, Guido

2010-01-01

’d tongues in the frequency–amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devil’s staircase picture. The results account for numerical and experimental findings presented in the literature for special driving terms...

One-Pot Synthesis, X-Ray Diffraction and MAS NMR Spectroscopic Study of Gallosilicate Nitrate Cancrinite Na8[GaSiO4]6(NO34(H2O6

Directory of Open Access Journals (Sweden)

Ashok V. Borhade

2010-01-01

Full Text Available One-pot synthetic gallosilicate nitrate cancrinite (CAN framework topology have been synthesized under hydrothermal conditions at 100 °C. The synthesized product was characterized by, X-ray powder diffraction, IR, Raman and 29Si, 23Na MAS NMR spectroscopy, SEM and thermogravimetry. The crystal structure refinement of pure nitrate cancrinite has been carried out from X-ray data using Rietveld refinement method. Gallosilicate cancrinite Na8[GaSiO4]6(NO34(H2O6 crystalline hexagonal with space group P63 and a = 12.77981 Å (2, c = 5.20217 Å (1, (Rwp = 0.0696 Rp = 0.0527. The results by MAS NMR spectroscopy confirmed the alternating Si, Ga ordering of the gallosilicate framework for a Si/Ga ratio of 1.0. A distribution of the quadrupolar interaction of the sodium cations caused by the enclatherated water molecules and motional effects can be suggested from the 23Na MAS NMR. Thermogravimetric investigation shows the extent of nitrate entrapment, stability within the cancrinite cage and decomposition properties. SEM clearly shows the hexagonal needle shaped crystals of nitrate cancrinite.

Mode coupling of Schwarzschild perturbations: Ringdown frequencies

International Nuclear Information System (INIS)

Pazos, Enrique; Brizuela, David; Martin-Garcia, Jose M.; Tiglio, Manuel

2010-01-01

Within linearized perturbation theory, black holes decay to their final stationary state through the well-known spectrum of quasinormal modes. Here we numerically study whether nonlinearities change this picture. For that purpose we study the ringdown frequencies of gauge-invariant second-order gravitational perturbations induced by self-coupling of linearized perturbations of Schwarzschild black holes. We do so through high-accuracy simulations in the time domain of first and second-order Regge-Wheeler-Zerilli type equations, for a variety of initial data sets. We consider first-order even-parity (l=2, m=±2) perturbations and odd-parity (l=2, m=0) ones, and all the multipoles that they generate through self-coupling. For all of them and all the initial data sets considered we find that--in contrast to previous predictions in the literature--the numerical decay frequencies of second-order perturbations are the same ones of linearized theory, and we explain the observed behavior. This would indicate, in particular, that when modeling or searching for ringdown gravitational waves, appropriately including the standard quasinormal modes already takes into account nonlinear effects.

Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX

International Nuclear Information System (INIS)

Gorelenkov, N.N.; Medley, S.S.

2004-01-01

Beam ion transport in the presence of low frequency MHD activity in National Spherical Tokamak Experiment (NSTX) plasma is modeled numerically and analyzed theoretically in order to understand basic underlying physical mechanisms responsible for the observed fast ion redistribution and losses. Numerical modeling of the beam ions flux into the NPA in NSTX shows that after the onset of low frequency MHD activity high energy part of beam ion distribution, E b > 40keV, is redistributed radially due to stochastic diffusion. Such diffusion is caused by high order harmonics of the transit frequency resonance overlap in the phase space. Large drift orbit radial width induces such high order resonances. Characteristic confinement time is deduced from the measured NPA energy spectrum and is typically ∼ 4msec. Considered MHD activity may induce losses on the order of 10% at the internal magnetic field perturbation (delta)B/B = Ο (10 -3 ), which is comparable to the prompt orbit losses

Source conductance scaling for high frequency superconducting quasiparticle receivers

Science.gov (United States)

Ke, Qing; Feldman, M. J.

1992-01-01

It has been suggested that the optimum source conductance G(sub s) for the superconductor-insulator-superconductor (SIS) quasiparticle mixer should have a l/f dependence. This would imply that the critical current density of SIS junctions used for mixing should increase as frequency squared, a stringent constraint on the design of submillimeter SIS mixers, rather than in simple proportion to frequency as previously believed. We have used Tucker's quantum theory of mixing for extensive numerical calculations to determine G(sub s) for an optimized SIS receiver. We find that G(sub s) is very roughly independent of frequency (except for the best junctions at low frequency), and discuss the implications of our results for the design of submillimeter SIS mixers.

Numerical analysis for the stick-slip vibration of a transversely moving beam in contact with a frictional wall

Science.gov (United States)

Won, Hong-In; Chung, Jintai

2018-04-01

This paper presents a numerical analysis for the stick-slip vibration of a transversely moving beam, considering both stick-slip transition and friction force discontinuity. The dynamic state of the beam was separated into the stick state and the slip state, and boundary conditions were defined for both. By applying the finite element method, two matrix-vector equations were derived: one for stick state and the other for slip state. However, the equations have different degrees of freedom depending on whether the end of a beam sticks or slips, so we encountered difficulties in time integration. To overcome the difficulties, we proposed a new numerical technique to alternatively use the matrix-vector equations with different matrix sizes. In addition, to eliminate spurious high-frequency responses, we applied the generalized-α time integration method with appropriate value of high-frequency numerical dissipation. Finally, the dynamic responses of stick-slip vibration were analyzed in time and frequency domains: the dynamic behavior of the beam was explained to facilitate understanding of the stick-slip motion, and frequency characteristics of the stick-slip vibration were investigated in relation to the natural frequencies of the beam. The effects of the axial load and the moving speed upon the dynamic response were also examined.

Numerical Simulations of Hyperfine Transitions of Antihydrogen

CERN Document Server

Kolbinger, B.; Diermaier, M.; Lehner, S.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M.C.; Widmann, E.

2015-02-04

One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration's goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.

Numerical simulations of hyperfine transitions of antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Kolbinger, B., E-mail: bernadette.kolbinger@oeaw.ac.at; Capon, A.; Diermaier, M.; Lehner, S. [Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences (Austria); Malbrunot, C. [CERN (Switzerland); Massiczek, O.; Sauerzopf, C.; Simon, M. C.; Widmann, E. [Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences (Austria)

2015-08-15

One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration’s goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.

Numerical Solution of the Kzk Equation for Pulsed Finite Amplitude Sound Beams in Thermoviscous Fluids

Science.gov (United States)

Lee, Yang-Sub

A time-domain numerical algorithm for solving the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear parabolic wave equation is developed for pulsed, axisymmetric, finite amplitude sound beams in thermoviscous fluids. The KZK equation accounts for the combined effects of diffraction, absorption, and nonlinearity at the same order of approximation. The accuracy of the algorithm is established via comparison with analytical solutions for several limiting cases, and with numerical results obtained from a widely used algorithm for solving the KZK equation in the frequency domain. The time domain algorithm is used to investigate waveform distortion and shock formation in directive sound beams radiated by pulsed circular piston sources. New results include predictions for the entire process of self-demodulation, and for the effect of frequency modulation on pulse envelope distortion. Numerical results are compared with measurements, and focused sources are investigated briefly.

Pengaruh Harga, Kualitas Produk, Dan Citra Merek Terhadap Keputusan Pembelian Kecap Manis Merek Bango (Studi Kasus Pada Ibu Rumah Tangga Di Komplek Villa Mutiara Johor Ii Dan Taman Johor Mas)

OpenAIRE

Nurlisa

2013-01-01

This research aims to determine the effects of pricing, product quality and brand image have a significant and positive impact on purchasing decision Bango soy sauce brands on housewife in Komplek Villa Mutiara Johor II and Taman Johor Mas. The population in this research was all the housewife in the Komplek Villa Mutiara Johor II and Taman Johor Mas. Data analyzing method is by using descriptive analyzing method and multiple linear regression. Kind of this research is causal comparative. Thi...

Numerical Simulation of Pressure Fluctuations in the Thermo-acoustic Transducer

Directory of Open Access Journals (Sweden)

D. A. Uglanov

2015-01-01

Full Text Available The article describes the features of numerical simulation of acoustic oscillation excitation in the resonators with a foam insert (regenerator to study the excitation of thermo-acoustic oscillations in the circuit of small-sized engine model on the pulse tube.The aim of this work is the numerical simulation of the emerging oscillations in thermoacoustic engine resonator at the standing wave. As a basis, the work takes a thermo-acoustic resonator model with the open end (without piston developed in DeltaEC software. The precalculated operation frequency of the given resonator model, as a quarter of the wave resonator, is ν = 560 Hz.The paper offers a simplified finite element resonator model and defines the harmonic law of the temperature distribution on regenerator. The time dependences of the speed and pressure amplitude for the open end of the resonator are given; the calculated value of the process operating frequency is approximately equal to the value of the frequency for a given length of the resonator. Key findings, as a result of study, are as follows:1. The paper shows a potential for using this ESI-CFD Advanced software to simulate the processes of thermal excitation of acoustic oscillations.2. Visualization of turbulent flow fluctuations in the regenerator zone extends the analysis capability of gas-dynamic processes.3. Difference between operating frequency of the process simulated by ESI-CFD Advanced and frequency value obtained by analytical methods is about 4%, which is evidence of the model applicability to study the acoustic parameters of thermo-acoustic transducers. Experimental results have proved these data.

[Clinical effect of high-frequency oscillatory ventilation combined with pulmonary surfactant in treatment of neonatal severe meconium aspiration syndrome complicated by pulmonary hemorrhage].

Science.gov (United States)

Huang, Jing; Lin, Xin-Zhu; Zheng, Zhi

2016-11-01

To study the clinical effect and safety of high-frequency oscillatory ventilation (HFOV) combined with pulmonary surfactant (PS) in the treatment of neonatal severe meconium aspiration syndrome (MAS) complicated by neonatal pulmonary hemorrhage (NPH). A total of 48 children with severe MAS complicated by NPH were enrolled, and a retrospective analysis was performed for the clinical effects of HFOV+PS (trial group, 25 children) and HFOV alone (control group, 23 children). The blood gas parameters, oxygenation index (OI), PaO 2 /FiO 2 (P/F) value, duration of pulmonary hemorrhage, ventilation time, length of hospital stay, incidence of complications, and outcome were compared between the two groups. At 6, 12, 24, and 48 hours after treatment, the trial group had significantly better PaO 2 , OI, and P/F value than the control group (Phemorrhage (P0.05). HFOV combined with PS can better improve oxygenation function and shorten the duration of NPH and ventilation time. Meanwhile, it does not increase the incidence of adverse events. Therefore, it is a safe and effective therapy.

High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

Energy Technology Data Exchange (ETDEWEB)

Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

2016-04-01

High field quantitative 27Al MAS NMR and temperature programmed desorption (TPD) of ethanol are used to study the surface and phase transformation of gamma-Al2O3 during calcination in the temperature range of 500 to 1300 degrees C. Following ethanol adsorption, ethylene is generated during TPD with a desorption temperature > 200 degrees C. With increasing calcination temperature prior to TPD, the amount of ethylene produced decreases monotonically. Significantly, 27Al MAS NMR reveals that the amount of penta-coordinate Al3+ ions (Lewis acid sites) also decreases with increasing calcination temperature. In fact, a strong correlation between the amount of penta-coordinate Al3+ ions and the amount of strongly adsorbed ethanol molecules (i.e., the ones that convert to ethylene during TPD) is obtained. This result indicates that the penta-coordinate aluminum sites are the catalytic active sites on alumina surfaces during ethanol dehydration reaction across the entire course of gamma- to alpha-Al2O3 phase transformations.

Personāla atlases un apmācības sistēmas pilnveidošana uzņēmumā "X"

OpenAIRE

Strode, Gunta

2012-01-01

Bakalaura darbā „Personāla atlases un apmācības sistēmas pilnveidošana uzņēmumā „X” ” tiek izskatīti un analizēti jautājumi par personāla atlases un apmācības procesu. Darbs sastāv no trim daļām. Pirmajā daļā tiek raksturoti personāla atlases mērķi un atlases organizēšanas kārtība. Otrajā daļā tiek raksturota personāla apmācības nozīme un organizēšanas nosacījumi. Trešajā daļā tiek pētīta personāla atlases un apmācības sistēmas pilnveidošana uzņēmumā „X”. Pamatojoties uz veiktajiem ...

Preču uzskaites sistēmas izstrāde Django ietvarā

OpenAIRE

Kokorevičs, Miķelis

2014-01-01

Django ietvars ir moderns un pilnvērtīgs tīmekļa ietvars, kas ir veidots Python programmēšanas valodā. Šajā darbā, tiek pētīta Django ietvara funkcionalitāte un piemērotība individuālu preču uzskaites sistēmu izstrādē. Galvenie darba uzdevumi ir izpētīt Django ietvara iespējas un apkopot preču uzskaites sistēmas izstrādei nozīmīgākās priekšrocības. Šī darba rezultātā, tika aprakstīta Django ietvara funkcionalitāte, iespējas un uzbūve. Tika veikts salīdzinājums starp populārākajiem Pyth...

Eigenmode frequency distribution of rapidly rotating neutron stars

International Nuclear Information System (INIS)

Boutloukos, Stratos; Nollert, Hans-Peter

2007-01-01

We use perturbation theory and the relativistic Cowling approximation to numerically compute characteristic oscillation modes of rapidly rotating relativistic stars which consist of a perfect fluid obeying a polytropic equation of state. We present a code that allows the computation of modes of arbitrary order. We focus here on the overall distribution of frequencies. As expected, we find an infinite pressure mode spectrum extending to infinite frequency. In addition we obtain an infinite number of inertial mode solutions confined to a finite, well-defined frequency range which depends on the compactness and the rotation frequency of the star. For nonaxisymmetric modes we observe how this range is shifted with respect to the axisymmetric ones, moving towards negative frequencies and thus making all m>2 modes unstable. We discuss whether our results indicate that the star's spectrum must have a continuous part, as opposed to simply containing an infinite number of discrete modes

Nevalstiskās organizācijas "Centra Dardedze" sociālo reklāmas kampaņu video materiālu vēstījuma un auditorijas uzmanības piesaistošo elementu analīze

OpenAIRE

Kolbina, Inese

2016-01-01

Bakalaura darbā „Nevalstiskās organizācijas "Centra Dardedze" sociālo reklāmas kampaņu video materiālu vēstījuma un auditorijas uzmanības piesaistošo elementu analīze” tika analizētas nevalstiskās organizācijas "Centrs Dardedze" seši sociālo reklāmu video materiāli. Analīze balstās uz reklāmas vizuālo vēstījumu un auditorijas uztveres izpēti. Bakalaura darba mērķis ir izpētīt "Centrs Dardedze" reklāmas kampaņas, noskaidrot kā un ar kādiem paņēmieniem konkrētās sociālās reklāmas cenšas mainīt...

Day-Ahead Scheduling Considering Demand Response as a Frequency Control Resource

Directory of Open Access Journals (Sweden)

Yu-Qing Bao

2017-01-01

Full Text Available The development of advanced metering technologies makes demand response (DR able to provide fast response services, e.g., primary frequency control. It is recognized that DR can contribute to the primary frequency control like thermal generators. This paper proposes a day-ahead scheduling method that considers DR as a frequency control resource, so that the DR resources can be dispatched properly with other resources. In the proposed method, the objective of frequency control is realized by defining a frequency limit equation under a supposed contingency. The frequency response model is used to model the dynamics of system frequency. The nonlinear frequency limit equation is transformed to a linear arithmetic equation by piecewise linearization, so that the problem can be solved by mixed integer linear programming (MILP. Finally, the proposed method is verified on numerical examples.

Transparency of Magnetized Plasma at Cyclotron Frequency

International Nuclear Information System (INIS)

G. Shvets; J.S. Wurtele

2002-03-01

Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of the nonlocal plasma oscillation. The complexity of the plasma system results in an index of refraction at the cyclotron frequency that differs from unity. Lagrangian description was used to elucidate the physics and enable numerical simulation of the plasma transparency and control of group and phase velocity. This control naturally leads to applications for electromagnetic pulse compression in the plasma and electron/ion acceleration

Computer-Aided Numerical Inversion of Laplace Transform

Directory of Open Access Journals (Sweden)

Umesh Kumar

2000-01-01

Full Text Available This paper explores the technique for the computer aided numerical inversion of Laplace transform. The inversion technique is based on the properties of a family of three parameter exponential probability density functions. The only limitation in the technique is the word length of the computer being used. The Laplace transform has been used extensively in the frequency domain solution of linear, lumped time invariant networks but its application to the time domain has been limited, mainly because of the difficulty in finding the necessary poles and residues. The numerical inversion technique mentioned above does away with the poles and residues but uses precomputed numbers to find the time response. This technique is applicable to the solution of partially differentiable equations and certain classes of linear systems with time varying components.

Numerical integration for ab initio many-electron self energy calculations within the GW approximation

Energy Technology Data Exchange (ETDEWEB)

Liu, Fang, E-mail: fliu@lsec.cc.ac.cn [School of Statistics and Mathematics, Central University of Finance and Economics, Beijing 100081 (China); Lin, Lin, E-mail: linlin@math.berkeley.edu [Department of Mathematics, University of California, Berkeley, CA 94720 (United States); Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Vigil-Fowler, Derek, E-mail: vigil@berkeley.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lischner, Johannes, E-mail: jlischner597@gmail.com [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kemper, Alexander F., E-mail: afkemper@lbl.gov [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sharifzadeh, Sahar, E-mail: ssharifz@bu.edu [Department of Electrical and Computer Engineering and Division of Materials Science and Engineering, Boston University, Boston, MA 02215 (United States); Jornada, Felipe H. da, E-mail: jornada@berkeley.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Deslippe, Jack, E-mail: jdeslippe@lbl.gov [NERSC, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Yang, Chao, E-mail: cyang@lbl.gov [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); and others

2015-04-01

We present a numerical integration scheme for evaluating the convolution of a Green's function with a screened Coulomb potential on the real axis in the GW approximation of the self energy. Our scheme takes the zero broadening limit in Green's function first, replaces the numerator of the integrand with a piecewise polynomial approximation, and performs principal value integration on subintervals analytically. We give the error bound of our numerical integration scheme and show by numerical examples that it is more reliable and accurate than the standard quadrature rules such as the composite trapezoidal rule. We also discuss the benefit of using different self energy expressions to perform the numerical convolution at different frequencies.

Efektifitas Nannochloropsis sp. terhadap sistem imun non-spesifik ikan mas Cyprinus carpio yang diinfeksi Virus Herpes

Directory of Open Access Journals (Sweden)

Arafik Lamadi

2017-11-01

Full Text Available The aim of this research was to determine the effect of Nannochlorpsisis sp. against the common carp (Cyprinus carpio leukocyte profile, infected with Koi Hepesvirus (KHV. The  descriptive observational method wa used in this study. This research was conducted for 4 weeks, using common carp length 12±0,3 cm as many as 7 fish. The tested experiment was P1: without infested by Nannochlorpsisis sp. and KH; P2: Infested by  Nannochlorpsisis sp. and without KHV infected; P3: Infected by Nannochloropsis sp. and KHV; P4;  Not infected by Nannochlorpsisis sp. and  infected by KHV. Evey tratment in three replications. The results showed that the highest total leukocyte was obtained in P3 (37.600 cells/ml, followed by  P4 (29.650 cells / ml, P2 (28,500 cells / ml and P1 (21,150 cells / ml. Leukocyte differentiation test on P1 (neutrophil 6.2%, lymphocyte 68.0%, monocyte 17.0%, P2 (neutrophil 6.6%, lymphocyte 72.3%, monocyte 18.3%, P3 (neutrophil 7.9%, lymphocyte 66.1%, monocytes 24.3%, P4 (neutrophils 11.2%, lymphocytes 57.6%, monocytes 37.6%. The higher survivla rate was recorded in P2 (100%. It is concluded that  Nannochloropsis sp. can enhance the common carp immune sytem. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian Nannochlorpsis sp. terhadap profil leukosit ikan mas (Cyprinus carpio yang terinfeksi Koi Herves Virus (KHV. Penelitian ini menggunakan metode deskriptif observasional dengan membandingkan hasil pada perlakuan 1 P1: (tanpa pemberian Nannochlorpsis sp. dan tidak diinfeksi KHV, 2 P2 (diberikan Nannochlorpsis sp dan tanpa diinfeksi KHV, 3 P3 (diberikan Nannochlorpsisis sp dan diinfeksi KHV, 4 P4 (tanpa pemberian Nannochlorpsis sp. dan diinfeksi KHV, masing-masing perlakukan 3 kali ulangan. Penelitian ini dilakukan selama 4 minggu dengan menggunakan Ikan mas berukuran 12±0,3  cm sebanyak 120 ekor. Hasil perhitungan total leukosit tertinggi diperoleh pada P3 (37.600 sel/ml, selanjutnya berturut-turut  P4 (29.650  sel

Nonlinear ordinary differential equations analytical approximation and numerical methods

CERN Document Server

Hermann, Martin

2016-01-01

The book discusses the solutions to nonlinear ordinary differential equations (ODEs) using analytical and numerical approximation methods. Recently, analytical approximation methods have been largely used in solving linear and nonlinear lower-order ODEs. It also discusses using these methods to solve some strong nonlinear ODEs. There are two chapters devoted to solving nonlinear ODEs using numerical methods, as in practice high-dimensional systems of nonlinear ODEs that cannot be solved by analytical approximate methods are common. Moreover, it studies analytical and numerical techniques for the treatment of parameter-depending ODEs. The book explains various methods for solving nonlinear-oscillator and structural-system problems, including the energy balance method, harmonic balance method, amplitude frequency formulation, variational iteration method, homotopy perturbation method, iteration perturbation method, homotopy analysis method, simple and multiple shooting method, and the nonlinear stabilized march...

Efficient coding schemes with power allocation using space-time-frequency spreading

Institute of Scientific and Technical Information of China (English)

Jiang Haining; Luo Hanwen; Tian Jifeng; Song Wentao; Liu Xingzhao

2006-01-01

An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.

Design and Evaluation of Autonomous Hybrid Frequency-Voltage Sensitive Load Controller

DEFF Research Database (Denmark)

Douglass, Philip James; Garcia-Valle, Rodrigo; Sossan, Fabrizio

2013-01-01

The paper introduces an algorithm for control of autonomous loads without digital communication interfaces to provide both frequency regulation and voltage regulation services. This hybrid controller can be used to enhance frequency sensitive loads to mitigate line overload arising from reduced l...... load diversity. Numerical simulations of the hybrid controller in a representative distribution system show the peak system load was reduced by 12% compared to a purely frequency sensitive load controller.......The paper introduces an algorithm for control of autonomous loads without digital communication interfaces to provide both frequency regulation and voltage regulation services. This hybrid controller can be used to enhance frequency sensitive loads to mitigate line overload arising from reduced...

Numerical solutions of the linearized Euler equations for unsteady vortical flows around lifting airfoils

Science.gov (United States)

Scott, James R.; Atassi, Hafiz M.

1990-01-01

A linearized unsteady aerodynamic analysis is presented for unsteady, subsonic vortical flows around lifting airfoils. The analysis fully accounts for the distortion effects of the nonuniform mean flow on the imposed vortical disturbances. A frequency domain numerical scheme which implements this linearized approach is described, and numerical results are presented for a large variety of flow configurations. The results demonstrate the effects of airfoil thickness, angle of attack, camber, and Mach number on the unsteady lift and moment of airfoils subjected to periodic vortical gusts. The results show that mean flow distortion can have a very strong effect on the airfoil unsteady response, and that the effect depends strongly upon the reduced frequency, Mach number, and gust wave numbers.

Low frequency electric and magnetic fields - the topic of cancer

International Nuclear Information System (INIS)

Thommesen, G.

1988-01-01

A review is made of the literature about the biological effects of low frequency electric and magnetic fields. It is still an unsettled question whether extremely low frequency magnetic fields may increase the incidence of cancer. Experimental data arise mainly from exposure to field strengths or frequencies seldom or never encountered by people. The results give no clear explanation to the increase in cancer incidence reported in epidemiological works. The spectre of possible mechanisms imply that no simple dose/effect relationship should be expected, as conflicting mechanisms may dominate at different exposure levels. There is therefore no basis at present for giving numerical value to cancer risk from exposure to low frequency electric or magnetic fields

High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

Energy Technology Data Exchange (ETDEWEB)

Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

2016-04-01

Gamma-, sigma- and theta-Al2O3 are well known metastable “transitional” alumina structural polymorphs. Upon heating, Al2O3 transitions to the so-called and Al2O3 polymorphs and finally forms the thermally stable Al2O3. The poorly developed crystallinity and co-existence of the , , and Al2O3 prior to forming all Al2O3, making it difficult to characterize the structures as well as to quantify the various phases of the transition alumina. As a result, there are significant controversies in the literatures. In this work, a detailed NMR analysis was carried out at high magnetic field on three special aluminum oxide samples where the, , , Al2O3 phases are made dominant, respectively, by controlling the synthesis conditions. The goal is to simplify, including making unambiguous, spectral assignments in 27Al MAS NMR spectra of transition alumina that have not yet been commonly agreed previously. Specifically, quantitative 1D 27Al MAS NMR was used to quantify the ratios of the different alumina structural units, 2D MQMAS 27Al MAS was used for obtaining the highest spectral resolution to guide the analysis of the 1D spectrum, and a saturation pulse sequence was integrated into the 1D NMR to select the amorphous structures, including obtain spectra where the penta-coordinate sites are observed with enhanced relative intensity. Collectively, this study uniquely assigns Al-peaks (both octahedral and tetrahedral) to the Al2O3 and the Al2O3 phases and offers a new way of understanding, including quantifying, the different structural units and sites in transition alumina samples.

Productivity differences and food security: a metafrontier analysis of rain-fed maize farmers in MasAgro in Mexico

Directory of Open Access Journals (Sweden)

M. Laura Donnet

2017-04-01

Full Text Available Rain-fed maize production in Mexico includes approximately 6 million hectares which variation in productivity represents huge challenges to meeting the sustainable intensification goals of the Sustainable Modernization of Traditional Agriculture (MasAgro program. We use the information available from farmers participating in this program to investigate the differences in productivity and the effects of the promoted practices and technologies in seven defined rain-fed maize regions. We do this by applying metafrontier analysis to measure the technical efficiency and the technology gap. The results show a range of technical efficiency from 70 to 100%, which indicates the gains that can be achieved through improved management of the current inputs and practices of farmers in the program, and a range of the environment–technology gap between 32 and 82%, which indicates the limitations of the production environment which would require innovations in technologies and policies particularly adapted for the dry, the tropical and the more traditional regions. Furthermore, the results show that the use of hybrid seed and selling into maize markets have the largest impact in increasing maize yields in all regions. The difference between the MasAgro farmers and the average farmers in each region suggest that scaling the project will contribute to increasing maize production and Mexico’s food self-sufficiency.

Os desastres podem até cair dos céus... Mas a culpa não é de Deus

Directory of Open Access Journals (Sweden)

Josué Petrônio Quirino de Oliveira

2014-12-01

Full Text Available O propósito desta pesquisa é apresentar uma reflexão sobre o descaso em que a politica de enfrentamento aos desastres naturais vem sendo abordada no Brasil nos últimos 100 anos.  Com uma população cada vez mais urbana as cidades passam a ser o centro não só do poder econômico e político, mas também dos mais diversos eventos decorrentes das mudanças climáticas. Uma série de problemas agrava essa urbanização vulnerável e desencadeiam uma crise socioambiental determinada por fatores sociais, políticos, econômicos, tecnológicos, culturais e ecológicos que, de forma integrada, provocam consequências devastadoras. Inundações, deslizamentos, ciclones, incêndios florestais, enxurradas, estiagens, enchentes, secas e terremotos provocam impactos inesperados e pressionam ainda mais este quadro urbano complexo a uma dinâmica preocupante. O desastre não são as principais ameaças, mas a incapacidade de planejamento e enfrentamento na gestão dos desastres demostraram o descaso com a questão foi tratado no país ao longo de décadas.

Neural pulse frequency modulation of an exponentially correlated Gaussian process

Science.gov (United States)

Hutchinson, C. E.; Chon, Y.-T.

1976-01-01

The effect of NPFM (Neural Pulse Frequency Modulation) on a stationary Gaussian input, namely an exponentially correlated Gaussian input, is investigated with special emphasis on the determination of the average number of pulses in unit time, known also as the average frequency of pulse occurrence. For some classes of stationary input processes where the formulation of the appropriate multidimensional Markov diffusion model of the input-plus-NPFM system is possible, the average impulse frequency may be obtained by a generalization of the approach adopted. The results are approximate and numerical, but are in close agreement with Monte Carlo computer simulation results.

Numerical study of the aerodynamics of sound sources in a bass-reflex port

Directory of Open Access Journals (Sweden)

V.M. Garcia-Alcaide

2017-01-01

Full Text Available The aim of this paper is to study the aerodynamics phenomena of a bass-reflex port that causes noise in the audible frequency range. After discarding structural and mechanical vibration issues, the hypothesis considered is that vortex shedding is the source of the noise. Experimental and numerical evidences of the vortex, an analysis of its noise and the similarities between real and simulated performance are presented. The numerically simulated cases with the original geometry are excited at different frequencies and with modifications of the port geometry. Likewise, the internal performance of an enclosure with a closed port was simulated. The simulations have been performed with axisymmetrical geometries using the open-source OpenFOAM® toolbox. Moreover, experimental measurements were carried out. First, acoustic signal experiments were done to analyse the response of the bass-reflex ports. Secondly, a structure vibration measurement was conducted in order to exclude the cabinet structure vibration as a source of the noise in question. A good agreement was found between numerical and experimental results, especially in the frequency band of the detected noise, i.e. the 1000–1500 Hz range. Despite no remarkable improvement being made with the geometry changes explored, the presented CFD approach has proved a useful and cost-effective tool to address this kind of phenomenon.

Numerical Simulation of Sloshing Phenomena in Cubic Tank with Multiple Baffles

Directory of Open Access Journals (Sweden)

Mi-An Xue

2012-01-01

Full Text Available A two-phase fluid flow model solving Navier-Stokes equations was employed in this paper to investigate liquid sloshing phenomena in cubic tank with horizontal baffle, perforated vertical baffle, and their combinatorial configurations under the harmonic motion excitation. Laboratory experiment of liquid sloshing in cubic tank with perforated vertical baffle was carried out to validate the present numerical model. Fairly good agreements were obtained from the comparisons between the present numerical results and the present experimental data, available numerical data. Liquid sloshing in cubic tank with multiple baffles was investigated numerically in detail under different external excitation frequencies. Power spectrum of the time series of free surface elevation was presented with the aid of fast Fourier transform technique. The dynamic impact pressures acting on the normal and parallel sidewalls were discussed in detail.

High-frequency asymptotics of the local vertex function. Algorithmic implementations

Energy Technology Data Exchange (ETDEWEB)

Tagliavini, Agnese; Wentzell, Nils [Institut fuer Theoretische Physik, Eberhard Karls Universitaet, 72076 Tuebingen (Germany); Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Li, Gang; Rohringer, Georg; Held, Karsten; Toschi, Alessandro [Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Taranto, Ciro [Institute for Solid State Physics, Vienna University of Technology, 1040 Vienna (Austria); Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Andergassen, Sabine [Institut fuer Theoretische Physik, Eberhard Karls Universitaet, 72076 Tuebingen (Germany)

2016-07-01

Local vertex functions are a crucial ingredient of several forefront many-body algorithms in condensed matter physics. However, the full treatment of their frequency dependence poses a huge limitation to the numerical performance. A significant advancement requires an efficient treatment of the high-frequency asymptotic behavior of the vertex functions. We here provide a detailed diagrammatic analysis of the high-frequency asymptotic structures and their physical interpretation. Based on these insights, we propose a frequency parametrization, which captures the whole high-frequency asymptotics for arbitrary values of the local Coulomb interaction and electronic density. We present its algorithmic implementation in many-body solvers based on parquet-equations as well as functional renormalization group schemes and assess its validity by comparing our results for the single impurity Anderson model with exact diagonalization calculations.

Frequency dependence of magnetic shielding performance of HTS plates in mixed states

International Nuclear Information System (INIS)

Kamitani, Atsushi; Yokono, Takafumi; Yokono, Takafumi

2000-01-01

The magnetic shielding performance of the high-Tc superconducting (HTS) plate is investigated numerically. The behavior of the shielding current density in the HTS plate is expressed as the integral-differential equation with a normal component of the current vector potential as a dependent variable. The numerical code for solving the equation has been developed by using the combination of the Newton-Raphson method and the successive substitution method and, by use of the code, damping coefficients and shielding factors are evaluated for the various values of the frequency ω. The results of computations show that the HTS plate has a possibility of shielding the high-frequency magnetic field with ω > or approx. 1 kHz. (author)

Frequency dependence of magnetic shielding performance of HTS plates in mixed states

Energy Technology Data Exchange (ETDEWEB)

Kamitani, Atsushi; Yokono, Takafumi [Yamagata Univ., Yonezawa (Japan). Faculty of Engineering; Yokono, Takafumi [Tsukuba Univ., Ibaraki (Japan). Inst. of Information Sciences and Electronics

2000-06-01

The magnetic shielding performance of the high-Tc superconducting (HTS) plate is investigated numerically. The behavior of the shielding current density in the HTS plate is expressed as the integral-differential equation with a normal component of the current vector potential as a dependent variable. The numerical code for solving the equation has been developed by using the combination of the Newton-Raphson method and the successive substitution method and, by use of the code, damping coefficients and shielding factors are evaluated for the various values of the frequency {omega}. The results of computations show that the HTS plate has a possibility of shielding the high-frequency magnetic field with {omega} > or approx. 1 kHz. (author)

Characteristics and Sampling Efficiencies of Two Impactor Bioaerosol Samplers: MAS-100(Registered) (Microbial Air Monitoring System) and Single-Stage Andersen Viable Microbial Samplers

National Research Council Canada - National Science Library

Hottell, K

2004-01-01

.... A petri dish with agar is used as the impaction surface for these samplers. The MAS-l00 is a single-stage impactor that aspirates air through a 400-hole perforated entry plate onto an agar plate at an airflow rate of 100 L/min...

A MAS NMR and DRIFT study of the Ga species in Ga/H-ZSM5 catalysts and their effect on propane ammoxidation

NARCIS (Netherlands)

Pal, P.; Quartararo, J.; Hamid, abd S.B.; Derouane, E.G.; Védrine, J.C.; Magusin, P.C.M.M.; Anderson, B.G.

2005-01-01

71Ga, 27Al and 29Si MAS-NMR and DRIFT spectroscopies were used to characterize the state of gallium in Ga/H-ZSM5 catalysts tested for their ability to catalyse the ammoxidation of propane. Ga-species were observed in two different possible environments: octahedrally-coordinated gallium in small

Written Exercises: Ancestral Magic and Emergent Intellectuals in Mia Couto, Lhoussain Azergui and Dorota Masłowska

Directory of Open Access Journals (Sweden)

Ewa Łukaszyk

2016-12-01

Full Text Available Written Exercises: Ancestral Magic and Emergent Intellectuals in Mia Couto, Lhoussain Azergui and Dorota Masłowska The article consists in a comparative reading of three novels: Um rio chamado tempo by Mia Couto, Le pain des corbeaux by Lhoussain Azergui and Paw królowej by Dorota Masłowska. In spite of the difference of the historical circumstances of Mozambique, Morocco and Poland, these three books meet at an intersecting point: the emergence of an intelligentsia that uses literacy and writing as an instrument to deconstruct the post-colonial concept of nation and to operate a trans-colonial renegotiation of identity. By the notion of trans-colonial, I understand the opposition against new kinds of symbolic violence that emerged after the end of the colonial period; here this new form of oppression is related to the concept of national unity – an artificial construct that leaves no place for a dualism or pluralism of cultural reality (two shores of the Zambezi river, Arab and Berber dualism in Morocco, “small homelands” in Poland. The young heroes of the novels grasp the pen in order to break through the falseness or the taboos created by the fathers, establishing, at the same time, the relation of solidarity with the world of the grandfathers. The act of writing becomes an actualization of the ancestral universe of magic. The settlement of accounts with the parental generation concerns the vision of nation built upon the resistance against the colonizer (it also refers to the Polish cultural formation, based on the tradition of uprisings and resistance against the Russians.   Ćwiczenia pisemne: magia przodków i nowi intelektualiści w powieściach Mii Couto, Lhoussaina Azerguiego i Doroty Masłowskiej Na podstawie powieści Um rio chamado tempo, uma casa chamada terra Mii Couto (2002, Le pain des corbeaux Lhoussaina Azerguiego (2012 oraz Paw królowej Doroty Masłowskiej (2005 dokonano analizy zjawiska wyłonienia się nowej

Virtual photons in imaginary time: Computing exact Casimir forces via standard numerical electromagnetism techniques

International Nuclear Information System (INIS)

Rodriguez, Alejandro; Ibanescu, Mihai; Joannopoulos, J. D.; Johnson, Steven G.; Iannuzzi, Davide

2007-01-01

We describe a numerical method to compute Casimir forces in arbitrary geometries, for arbitrary dielectric and metallic materials, with arbitrary accuracy (given sufficient computational resources). Our approach, based on well-established integration of the mean stress tensor evaluated via the fluctuation-dissipation theorem, is designed to directly exploit fast methods developed for classical computational electromagnetism, since it only involves repeated evaluation of the Green's function for imaginary frequencies (equivalently, real frequencies in imaginary time). We develop the approach by systematically examining various formulations of Casimir forces from the previous decades and evaluating them according to their suitability for numerical computation. We illustrate our approach with a simple finite-difference frequency-domain implementation, test it for known geometries such as a cylinder and a plate, and apply it to new geometries. In particular, we show that a pistonlike geometry of two squares sliding between metal walls, in both two and three dimensions with both perfect and realistic metallic materials, exhibits a surprising nonmonotonic ''lateral'' force from the walls

A double-panel active segmented partition module using decoupled analog feedback controllers: numerical model.

Science.gov (United States)

Sagers, Jason D; Leishman, Timothy W; Blotter, Jonathan D

2009-06-01

Low-frequency sound transmission has long plagued the sound isolation performance of lightweight partitions. Over the past 2 decades, researchers have investigated actively controlled structures to prevent sound transmission from a source space into a receiving space. An approach using active segmented partitions (ASPs) seeks to improve low-frequency sound isolation capabilities. An ASP is a partition which has been mechanically and acoustically segmented into a number of small individually controlled modules. This paper provides a theoretical and numerical development of a single ASP module configuration, wherein each panel of the double-panel structure is independently actuated and controlled by an analog feedback controller. A numerical model is developed to estimate frequency response functions for the purpose of controller design, to understand the effects of acoustic coupling between the panels, to predict the transmission loss of the module in both passive and active states, and to demonstrate that the proposed ASP module will produce bidirectional sound isolation.

A general numerical analysis of the superconducting quasiparticle mixer

Science.gov (United States)

Hicks, R. G.; Feldman, M. J.; Kerr, A. R.

1985-01-01

For very low noise millimeter-wave receivers, the superconductor-insulator-superconductor (SIS) quasiparticle mixer is now competitive with conventional Schottky mixers. Tucker (1979, 1980) has developed a quantum theory of mixing which has provided a basis for the rapid improvement in SIS mixer performance. The present paper is concerned with a general method of numerical analysis for SIS mixers which allows arbitrary terminating impedances for all the harmonic frequencies. This analysis provides an approach for an examination of the range of validity of the three-frequency results of the quantum mixer theory. The new method has been implemented with the aid of a Fortran computer program.

Low Frequency Sloshing Analysis of Cylindrical Containers with Flat and Conical Baffles

Directory of Open Access Journals (Sweden)

Gnitko V.

2017-12-01

Full Text Available This paper presents an analysis of low-frequency liquid vibrations in rigid partially filled containers with baffles. The liquid is supposed to be an ideal and incompressible one and its flow is irrotational. A compound shell of revolution is considered as the container model. For evaluating the velocity potential the system of singular boundary integral equations has been obtained. The single-domain and multi-domain reduced boundary element methods have been used for its numerical solution. The numerical simulation is performed to validate the proposed method and to estimate the sloshing frequencies and modes of fluid-filled cylindrical shells with baffles in the forms of circular plates and truncated cones. Both axisymmetric and non-axisymmetric modes of liquid vibrations in baffled and un-baffled tanks have been considered. The proposed method makes it possible to determine a suitable place with a proper height for installing baffles in tanks by using the numerical experiment.

Frequency up-conversion and spectral breaking of a high power microwave pulse propagation in a self-generated plasma

International Nuclear Information System (INIS)

Kuo, S.P.; Ren, A.

1993-01-01

The main concern of the propagation of high power microwave pulse is the energy loss of the pulse before reaching the destination. The loss is caused by self-generated plasma. There are two processes which are responsible for the energy loss (so called tail erosion). They are collisional damping and cutoff reflection. In very high power region, the cutoff reflection is much more severe than the collisional damping. A frequency up-conversion process may help to avoid the cutoff reflection of powerful electromagnetic pulse propagating in a self-generated plasma. Both chamber experiments and numerical simulation are performed. When the field amplitude only slightly exceeds the breakdown threshold field of the background gas, the result shows that the carrier frequency ω of the pulse shifts upward during the growth of local plasma frequency ωpe 2 . Thus, the self-generated plasma remains underdense to the pulse. However, the spectrum of the pulse starts to break up into two major peaks when the amplitude of the pulse is further increased. The frequency of one of the peaks is lower than the original carrier frequency and that of the other peak is higher than the original carrier frequency. These phenomena are observed both experimentally and numerically. The frequency down shift result is believed to be caused by damping mechanisms. Good agreement between the experimental results and the numerical simulation is obtained

1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

International Nuclear Information System (INIS)

Arévalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernández-Maldonado, Arturo J.

2012-01-01

The location of extraframework cations in Sr 2+ and Ba 2+ ion-exchanged SAPO-34 was estimated by means of 1 H and 23 Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO 2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO 2 adsorption performance. Highlights: ► Location of extraframework Sr 2+ or Ba 2+ cations was estimated by means of 1 H and 23 Na MAS NMR. ► Level of Sr 2+ or Ba 2+ ion exchange was limited by the presence of protons and sodium cations. ► Presence of ammonium cations in the supercages facilitated the exchange. ► Sr 2+ and Ba 2+ ion exchanged SAPOs are outstanding CO 2 adsorbents.

Numerical modeling of optical coherent transient processes with complex configurations-III: Noisy laser source

International Nuclear Information System (INIS)

Chang Tiejun; Tian Mingzhen

2007-01-01

A previously developed numerical model based on Maxwell-Bloch equations was modified to simulate optical coherent transient and spectral hole burning processes with noisy laser sources. Random walk phase noise was simulated using laser-phase sequences generated numerically according to the normal distribution of the phase shift. The noise model was tested by comparing the simulated spectral hole burning effect with the analytical solution. The noise effects on a few typical optical coherence transient processes were investigated using this numerical tool. Flicker and random walk frequency noises were considered in accumulation process

Tendencias clave para el tercer gobierno del MAS, Bolivia 2015-2019

Directory of Open Access Journals (Sweden)

Xavier Albó

2016-03-01

Esta presentación tiene como trasfondo el Plan Nacional de Desarrollo y pretende resaltar algunos de los logros del presidente Evo Morales y los desafíos que enfrenta en su tercer gobierno (2015-2019. Comienza revisando información demográfica básica, según el Censo de 2012, para luego centrarse en la economía: los hidrocarburos, la minería, la producción agropecuaria y la ecología. El boom de la quinua, la expansión de la frontera agrícola y la suspensión de la construcción de una carretera que atraviese el TIPNIS son algunos de los temas que se discuten. Internacionalmente, hay motivos de optimismo con relación a la demanda marítima de Bolivia, mientras que, a nivel nacional, el MAS aseguró una victoria parlamentaria en el año 2014. Las reformas menos exitosas son las del órgano judicial. La presentación termina revisando los movimientos sociales que permitieron la formación la de Asamblea Constituyente y el asunto de la autonomía municipal, departamental e indígena.

The effects of static quartic anharmonicity on the quantum dynamics of a linear oscillator with time-dependent harmonic frequency: Perturbative analysis and numerical calculations

International Nuclear Information System (INIS)

Sarkar, P.; Bhattacharyya, S.P.

1995-01-01

The effects of quartic anharmonicity on the quantum dynamics of a linear oscillator with time-dependent force constant (K) or harmonic frequency (ω) are studied both perturbatively and numerically by the time-dependent Fourier grid Hamiltonian method. In the absence of anharmonicity, the ground-state population decreases and the population of an accessible excited state (k = 2.4, 6 ... ) increases with time. However, when anharmonicity is introduced, both the ground- and excited-state populations show typical oscillations. For weak coupling, the population of an accessible excited state at a certain instant of time (short) turns out to be a parabolic function of the anharmonic coupling constant (λ), when all other parameters of the system are kept fixed. This parabolic nature of the excited-state population vs. the λ profile is independent of the specific form of the time dependence of the force constant, K t . However, it depends upon the rate at which K t relaxes. For small anharmonic coupling strength and short time scales, the numerical results corroborate expectations based on the first-order time-dependent perturbative analysis, using a suitably repartitioned Hamiltonian that makes H 0 time-independent. Some of the possible experimental implications of our observations are analyzed, especially in relation to intensity oscillations observed in some charge-transfer spectra in systems in which the dephasing rates are comparable with the time scale of the electron transfer. 21 refs., 7 figs., 1 tab

NUMERICAL STUDY OF ELECTROMAGNETIC WAVES GENERATED BY A PROTOTYPE DIELECTRIC LOGGING TOOL

Science.gov (United States)

To understand the electromagnetic waves generated by a prototype dielectric logging tool, a numerical study was conducted using both the finite-difference, time-domain method and a frequency- wavenumber method. When the propagation velocity in the borehole was greater than th...

A numerical simulation method and analysis of a complete thermoacoustic-Stirling engine.

Science.gov (United States)

Ling, Hong; Luo, Ercang; Dai, Wei

2006-12-22

Thermoacoustic prime movers can generate pressure oscillation without any moving parts on self-excited thermoacoustic effect. The details of the numerical simulation methodology for thermoacoustic engines are presented in the paper. First, a four-port network method is used to build the transcendental equation of complex frequency as a criterion to judge if temperature distribution of the whole thermoacoustic system is correct for the case with given heating power. Then, the numerical simulation of a thermoacoustic-Stirling heat engine is carried out. It is proved that the numerical simulation code can run robustly and output what one is interested in. Finally, the calculated results are compared with the experiments of the thermoacoustic-Stirling heat engine (TASHE). It shows that the numerical simulation can agrees with the experimental results with acceptable accuracy.

Mathematical and numerical models for eddy currents and magnetostatics with selected applications

CERN Document Server

Rappaz, Jacques

2013-01-01

This monograph addresses fundamental aspects of mathematical modeling and numerical solution methods of electromagnetic problems involving low frequencies, i.e. magnetostatic and eddy current problems which are rarely presented in the applied mathematics literature. In the first part, the authors introduce the mathematical models in a realistic context in view of their use for industrial applications. Several geometric configurations of electric conductors leading to different mathematical models are carefully derived and analyzed, and numerical methods for the solution of the obtained problem

Low frequency turbulence, particle and heat transport in the Wisconsin levitated octupole

International Nuclear Information System (INIS)

Garner, H.R.

1982-01-01

Low frequency turbulence in the drift frequency range and its relation to the observed particle transport in the Wisconsin Levitated Octupole has been studied with a microwave scattering apparatus. The experimental parameters were T/sub e/ approx. T/sub i/ 13 cm -3 , 200 G < B/sub p-average/ < 1.25 kG. The effect of shear on the transport was studied by the addition of a small toroidal field. By matching experimentally measured density profiles to those given by numerical solutions of the transport equations, diffusion coefficients were obtained. Time dependent density fluctuation spectra were measured with an 8 mm microwave scattering diagnostic to correlate the drift wave portion of the spectrum with the observed diffusion. The density fluctuation spectrum of low frequency (1 kHz < ω < 6 MHz) turbulence was measured for several values of perpendicular wavenumber, k/sub perpendicular to/. Electron heat transport was studied by fitting experimentally measured electron temperature profiles to those predicted by numerical solutions of electron energy transport equation

Hydration kinetics for the alite, belite, and calcium aluminate phase in Portland cements from 27Al and 29Si MAS NMR spectroscopy

DEFF Research Database (Denmark)

Skibsted, Jørgen; Jensen, Ole Mejlhede; Jakobsen, Hans Jørgen

1997-01-01

29Si magic-angle spinning (MAS) NMR spectroscopy is shown to be a valuable tool for obtaining the quantities of alite and belite in hydrated Portland cements. The hydration (1-180 days) of a white Portland cement with 10 wt.% silica fume added is investigated and the degrees of hydration for alite...

Analytic description of Raman-induced frequency shift in the case of non-soliton ultrashort pulses

Energy Technology Data Exchange (ETDEWEB)

Bugay, Aleksandr N., E-mail: bugay_aleksandr@mail.ru [Joint Institute for Nuclear Research, Joliot-Curie 6, 141980, Dubna, Moscow Region (Russian Federation); Khalyapin, Vyacheslav A., E-mail: slavasxi@gmail.com [Immanuel Kant Baltic Federal University, Kaliningrad, 236041 (Russian Federation); Kaliningrad State Technical University, Kaliningrad, 236000 (Russian Federation)

2017-01-30

Raman-induced frequency shift of ultrashort pulses have been studied extensively for the soliton propagation regime. Here we derive explicit analytic expressions for the evolution of Raman-induced frequency shift in much less studied case of non-soliton ultrashort pulses. Pulse spectra may belong to any region of group velocity dispersion including zero group dispersion point. The analysis is based on the moment method. Obtained expressions fit well to the numerical solution of the nonlinear wave equation. - Highlights: • Explicit analytic formulas for the evolution of Raman-induced frequency shift are derived in the case of non-soliton pulses. • Dynamics of non-soliton ultrashort pulses in the cases of positive and zero group dispersion is considered. • The deceleration and the saturation of Raman-induced frequency shift are analyzed. • The calculation relies on the moment method and fit well to the numerical solution of the nonlinear wave equation.

Analytic description of Raman-induced frequency shift in the case of non-soliton ultrashort pulses

International Nuclear Information System (INIS)

Bugay, Aleksandr N.; Khalyapin, Vyacheslav A.

2017-01-01

Raman-induced frequency shift of ultrashort pulses have been studied extensively for the soliton propagation regime. Here we derive explicit analytic expressions for the evolution of Raman-induced frequency shift in much less studied case of non-soliton ultrashort pulses. Pulse spectra may belong to any region of group velocity dispersion including zero group dispersion point. The analysis is based on the moment method. Obtained expressions fit well to the numerical solution of the nonlinear wave equation. - Highlights: • Explicit analytic formulas for the evolution of Raman-induced frequency shift are derived in the case of non-soliton pulses. • Dynamics of non-soliton ultrashort pulses in the cases of positive and zero group dispersion is considered. • The deceleration and the saturation of Raman-induced frequency shift are analyzed. • The calculation relies on the moment method and fit well to the numerical solution of the nonlinear wave equation.

Accurate simulation of Raman amplified lightwave synthesized frequency sweeper

DEFF Research Database (Denmark)

Pedersen, Anders Tegtmeier; Olesen, Anders Sig; Rottwitt, Karsten

2011-01-01

A lightwave synthesized frequency sweeper using a Raman amplifier for loss compensation is presented together with a numerical model capable of predicting the shape of individual pulses as well as the overall envelope of more than 100 pulses. The generated pulse envelope consists of 116 pulses wi...

Numerical investigations on axial and radial blade rubs in turbo-machinery

Science.gov (United States)

Abdelrhman, Ahmed M.; Tang, Eric Sang Sung; Salman Leong, M.; Al-Qrimli, Haidar F.; Rajamohan, G.

2017-07-01

In the recent years, the clearance between the rotor blades and stator/casing had been getting smaller and smaller prior improving the aerodynamic efficiency of the turbomachines as demand in the engineering field. Due to the clearance reduction between the blade tip and the rotor casing and between rotor blades and stator blades, axial and radial blade rubbing could be occurred, especially at high speed resulting into complex nonlinear vibrations. The primary aim of this study is to address the blade axial rubbing phenomenon using numerical analysis of rotor system. A comparison between rubbing caused impacts of axial and radial blade rubbing and rubbing forces are also aims of this study. Tow rotor models (rotor-stator and rotor casing models) has been designed and sketched using SOILDSWORKS software. ANSYS software has been used for the simulation and the numerical analysis. The rubbing conditions were simulated at speed range of 1000rpm, 1500rpm and 2000rpm. Analysis results for axial blade rubbing showed the appearance of blade passing frequency and its multiple frequencies (lx, 2x 3x etc.) and these frequencies will more excited with increasing the rotational speed. Also, it has been observed that when the rotating speed increased, the rubbing force and the harmonics frequencies in x, y and z-direction become higher and severe. The comparison study showed that axial blade rub is more dangerous and would generate a higher vibration impacts and higher blade rubbing force than radial blade rub.

Numerical simulation of dual frequency etching reactors: Influence of the external process parameters on the plasma characteristics

International Nuclear Information System (INIS)

Georgieva, V.; Bogaerts, A.

2005-01-01

A one-dimensional particle-in-cell/Monte Carlo model is used to investigate Ar/CF 4 /N 2 discharges sustained in capacitively coupled dual frequency reactors, with special emphasis on the influence of the reactor parameters such as applied voltage amplitudes and frequencies of the two voltage sources. The presented calculation results include plasma density, ion current, average sheath potential and width, electron and ion average energies and energy distributions, and ionization rates. The simulations were carried out for high frequencies (HFs) of 27, 40, 60, and 100 MHz and a low frequency (LF) of 1 or 2 MHz, varying the LF voltage and keeping the HF voltage constant and vice versa. It is observed that the decoupling of the two sources is possible by increasing the applied HF to very high values (above 60 MHz) and it is not defined by the frequency ratio. Both voltage sources have influence on the plasma characteristics at a HF of 27 MHz and to some extent at 40 MHz. At HFs of 60 and 100 MHz, the plasma density and ion flux are determined only by the HF voltage source. The ion energy increases and the ion energy distribution function (IEDF) becomes broader with HF or LF voltage amplitude, when the other voltage is kept constant. The IEDF is broader with the increase of HF or the decrease of LF

Novel structural flexibility identification in narrow frequency bands

International Nuclear Information System (INIS)

Zhang, J; Moon, F L

2012-01-01

A ‘Sub-PolyMAX’ method is proposed in this paper not only for estimating modal parameters, but also for identifying structural flexibility by processing the impact test data in narrow frequency bands. The traditional PolyMAX method obtains denominator polynomial coefficients by minimizing the least square (LS) errors of frequency response function (FRF) estimates over the whole frequency range, but FRF peaks in different structural modes may have different levels of magnitude, which leads to the modal parameters identified for the modes with small FRF peaks being inaccurate. In contrast, the proposed Sub-PolyMAX method implements the LS solver in each subspace of the whole frequency range separately; thus the results identified from a narrow frequency band are not affected by FRF data in other frequency bands. In performing structural identification in narrow frequency bands, not in the whole frequency space, the proposed method has the following merits: (1) it produces accurate modal parameters, even for the modes with very small FRF peaks; (2) it significantly reduces computation cost by reducing the number of frequency lines and the model order in each LS implementation; (3) it accurately identifies structural flexibility from impact test data, from which structural deflection under any static load can be predicted. Numerical and laboratory examples are investigated to verify the effectiveness of the proposed method. (paper)

Numerical Diffusion Effect in Dynamic Simulation of Thermohydraulic Systems

International Nuclear Information System (INIS)

Zanocco, Pablo; Gimenez, Marcelo; Delmastro, Dario

2003-01-01

In this work, the behavior of the explicit - up-wind method is studied in two phase natural convection circuit, near the instabilities boundaries.The effect of the numerical diffusion of the scheme upon the system stability is evaluated by means of linearization by small perturbations.The results are compared with a non-diffusive method, in the frequency domain, that solves analytically the linearized equations around a steady state condition.Moreover, a conservation equation transport model using the method of characteristics is implemented and studied.This method is compared with the explicit - up-wind scheme and it is found that it significantly reduces numerical diffusion in the equations solution. Several advantages are visualized for particular cases

Iterative procedures for wave propagation in the frequency domain

Energy Technology Data Exchange (ETDEWEB)

Kim, Seongjai [Rice Univ., Houston, TX (United States); Symes, W.W.

1996-12-31

A parallelizable two-grid iterative algorithm incorporating a domain decomposition (DD) method is considered for solving the Helmholtz problem. Since a numerical method requires choosing at least 6 to 8 grid points per wavelength, the coarse-grid problem itself is not an easy task for high frequency applications. We solve the coarse-grid problem using a nonoverlapping DD method. To accelerate the convergence of the iteration, an artificial damping technique and relaxation parameters are introduced. Automatic strategies for finding efficient parameters are discussed. Numerical results are presented to show the effectiveness of the method. It is numerically verified that the rate of convergence of the algorithm depends on the wave number sub-linearly and does not deteriorate as the mesh size decreases.

The numerical simulation of plasma flow in cylindrical resonant cavity of microwave plasma thruster

International Nuclear Information System (INIS)

Tang, J.-L.; He, H.-Q; Mao, G.-W.

2004-01-01

Microwave Plasma Thruster (MPT) is an electro-thermal propulsive device. MPT consists of microwave generator, gas storing and supplying system, resonant cavity and accelerative nozzle. It generates free-floating plasma brought by the microwave discharge breakdown gas in the resonant cavity, and the plasma exhausted from nozzle produces thrust. MPT has prospective application in spacecraft because of its advantages of high thrust, moderate specific impulse and high efficiency. In this paper, the numerical simulation of the coupling flow field of microwave plasma in resonant cavity under different frequencies will be discussed. The results of numerical simulation are as follows: 1) When the resonant model TM 011 was used, the higher the microwave frequency was, the smaller the size of MPT. The distribution of the electromagnetic field in small cavity, however, remain unchanged. 2) When the resonant model was used, the distribution of the temperature, the pressure and the electronic density in the resonant cavity remained unchanged under different resonant frequencies. 3) When the resonant frequency was increased with a fixed pressure distribution in a small cavity, compare to the MPT with lower frequency, the gas flow rate, the microwave power and the nozzle throat diameter of MPT all decreased. 4) The electromagnetic field in the cylindrical resonant cavity for all MPT with different frequencies was disturbed by the plasma formation. The strong disturbance happened in the region close to the plasma. (author)

Simulation and theory of spontaneous TAE frequency sweeping

International Nuclear Information System (INIS)

Wang Ge; Berk, H.L.

2012-01-01

A simulation model, based on the linear tip model of Rosenbluth, Berk and Van Dam (RBV), is developed to study frequency sweeping of toroidal Alfvén eigenmodes (TAEs). The time response of the background wave in the RBV model is given by a Volterra integral equation. This model captures the properties of TAE waves both in the gap and in the continuum. The simulation shows that phase space structures form spontaneously at frequencies close to the linearly predicted frequency, due to resonant particle–wave interactions and background dissipation. The frequency sweeping signals are found to chirp towards the upper and lower continua. However, the chirping signals penetrate only the lower continuum, whereupon the frequency chirps and mode amplitude increases in synchronism to produce an explosive solution. An adiabatic theory describing the evolution of a chirping signal is developed which replicates the chirping dynamics of the simulation in the lower continuum. This theory predicts that a decaying chirping signal will terminate at the upper continuum though in the numerical simulation the hole disintegrates before the upper continuum is reached. (paper)

Simulation and theory of spontaneous TAE frequency sweeping

Science.gov (United States)

Wang, Ge; Berk, H. L.

2012-09-01

A simulation model, based on the linear tip model of Rosenbluth, Berk and Van Dam (RBV), is developed to study frequency sweeping of toroidal Alfvén eigenmodes (TAEs). The time response of the background wave in the RBV model is given by a Volterra integral equation. This model captures the properties of TAE waves both in the gap and in the continuum. The simulation shows that phase space structures form spontaneously at frequencies close to the linearly predicted frequency, due to resonant particle-wave interactions and background dissipation. The frequency sweeping signals are found to chirp towards the upper and lower continua. However, the chirping signals penetrate only the lower continuum, whereupon the frequency chirps and mode amplitude increases in synchronism to produce an explosive solution. An adiabatic theory describing the evolution of a chirping signal is developed which replicates the chirping dynamics of the simulation in the lower continuum. This theory predicts that a decaying chirping signal will terminate at the upper continuum though in the numerical simulation the hole disintegrates before the upper continuum is reached.

Nonlinear parametric phenomena in plasma during radio frequency heating in the ion cyclotron frequency range

International Nuclear Information System (INIS)

Stepanov, K.N.

1996-01-01

Parametric phenomena in plasma which occur due to varying electric fields with the ion cyclotron frequency are reviewed. Beam-like lower hybrid instability emerges in strong pumping fields provided that the transverse relative velocity of particles is larger than the ion thermal speed (υ Ti ). The resulting turbulence and the following numerous manifestations observed experimentally are addressed. The turbulence may prove important for experiments aimed at plasma production or radio frequency (RF) cleaning of metallic surfaces of vacuum chambers in stellarators, tokamaks and helicon devices. In contrast, for a weak field (U Ti ) the kinetic parametric instabilities of ion cyclotron oscillations arise due to electrons. The issues of the turbulence, mathematical modelling, its role in turbulent heating observed on the torsatron Uragan-3M, decay instabilities associated with ion cyclotron oscillations and the triggering of ion quasimodes are considered. (author)

Numerical Simulation of the Vibration Behavior of Curved Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Sadegh Imani Yengejeh

2014-01-01

Full Text Available Several zigzag and armchair single-walled carbon nanotubes (CNTs were modeled by a commercial finite element package and their vibrational behavior was studied. Numerous computational tests with different boundary conditions and different bending angles were performed. Both computational and analytical results were compared. It was shown that the computational results are in good agreement with the analytical calculations in the case of straight tubes. In addition, it was concluded that the natural frequency of straight armchair and zigzag CNTs increases by increasing the chiral number of both armchair and zigzag CNTs. It was also revealed that the natural frequency of CNTs with higher chirality decreases by introducing bending angles. Nevertheless, the influence of increasing bending angle on the natural frequency of armchair and zigzag CNTs with lower chiral number is almost negligible.

Numerical Simulation of Liquid Sloshing Problem under Resonant Excitation

Directory of Open Access Journals (Sweden)

Fu-kun Gui

2014-04-01

Full Text Available Numerical simulations were conducted to investigate the fluid resonance in partially filled rectangular tank based on the OpenFOAM package of viscous fluid model. The numerical model was validated by the available theoretical, numerical, and experimental data. The study was mainly focused on the large amplitude sloshing motion and the corresponding impact force around the resonant condition. It was found that, for the 2D situation, the double pressure peaks happened near to the side walls around the still water level. And they were corresponding to the local free surface rising up and set-down, respectively. The impulsive loads on the tank corner with extreme magnitudes were observed as the free surface impacted the ceiling. The 3D numerical results showed that the free surface amplitudes along the side walls varied diversely, depending on the direction and frequency of the external excitation. The characteristics of the pressure around the still water level and tank ceiling were also presented. According to the computational results, it was found that the 2D numerical model can predict the impact loads near the still water level as accurately as 3D model. However, the impulsive pressure near the tank ceiling corner was remarkably underestimated.

Special frequencies and Lifshitz singularities in binary random harmonic chains

International Nuclear Information System (INIS)

Nieuwenhuizen, T.M.; Luck, J.M.; Canisius, J.; van Hemmen, J.L.; Ventevogel, W.J.

1986-01-01

The authors consider a one-dimensional chain of coupled harmonic oscillators; the mass of each atom is a random variable taking only two values (M or 1). They investigate the integrated density of states H(omega 2 ) near special frequencies: a given frequency omega/sub s/ with rational wavelength becomes special if the mass ratio M exceeds a certain critical value M/sub c/. They show that H has essential singularities of the types H/sub sg/∼ exp(-C 1 absolute value of omega 2 -omega/sub s/ 2 /sup 1/2/) or exp(-C 2 absolute value of omega 2 -omega/sub s/ 2 -1 ), according to the value of M and the sign of (omega 2 -omega/sub s/ 2 ). The Lifshitz singularity at the band edge is analyzed in the same way. In each case, the constant C 1 or C 2 is evaluated explicitly and compared with a vast amount of numerical work. All these exponential singularities are modulated by periodic amplitudes. The properties of the eigenfunctions with frequencies close to the special values are also discussed, and are illustrated by numerical data

Numerical modelling of complex resistivity effects on a homogeneous half-space at low frequencies

DEFF Research Database (Denmark)

Ingeman-Nielsen, Thomas; Baumgartner, François

2006-01-01

for environmental applications and thanks to technological progress, the use of wide band frequency equipment seems promising, and it is expected to shed light on the different results among the published solutions to the electromagnetic (EM) coupling problem. We review the theory of EM coupling over a homogeneous...

PAPARAN SENG DI PERAIRAN KALIGARANG TERHADAP EKSPRESI Zn-THIONEIN DAN KONSENTRASI SENG PADA HATI IKAN MAS

Directory of Open Access Journals (Sweden)

NK Dewi

2013-07-01

Full Text Available Penelitian bertujuan mengetahui paparan seng (Zn di perairan Kaligarang terhadap ekspresi Zn-thionein dan konsentrasi seng pada hati ikan mas (Cyprinus carpio L. Sebanyak 200 ekor ikan dibagi menjadi dua kelompok, masing-masing kelompok 100 ekor. Kelompok kontrol dipelihara di kolam ikan di Balai Benih Ikan Kabupaten Semarang, sedangkan kelompok perlakuan dipelihara pada karamba jaring apung di bagian hilir sungai Kaligarang. Setiap minggu sampel ikan diambil masing-masing lima ekor dari kedua kelompok secara acak untuk diambil organ hatinya dan dianalisis konsentrasi seng dan Zn-thionein. Ikan pada kedua kelompok dipelihara hingga Zn-thionein muncul pada hati ikan. Metallothionein diisolasi dari hati ikan dan dianalisis menggunakan metode High-Performance Liquid Chromatography, dengan larutan standar seng. Setiap satu minggu sekali, konsentrasi seng terlarut pada sampel air dari kedua kelompok diukur dengan metode Atomic Absorption Spectroscopy hingga Zn-thionein muncul. Hasil penelitian menunjukkan bahwa konsentrasi seng yang terlarut dalam air sungai Kaligarang adalah 0,078 mg/l, lebih tinggi dari nilai baku mutu air kelas I (0,05 mg/l. Rata-rata konsentrasi seng yang terabsorbi oleh hati ikan mas pada minggu ke-6 adalah 0,025868 mg/l, lebih rendah dari batas maksimum cemaran seng (100 mg/kg. Rata-rata konsentrasi seng pada hati ikan sebesar 0,025868 µg/g dapat menginduksi munculnya Zn-thionein pada hati ikan mas yang hidup di perairan Kaligarang pada minggu ke-6 perlakuan. The research aims to find concentration of dissolved zinc in the water of Kaligarang River and absorbed zinc concentration inside the liver of carp, also to analyze zinc exposure in Kaligarang River toward Zn-thionein induction inside the liver of carp. The concentration of dissolved zinc was measured using Atomic Absorption Spectroscopy method until Zn-thionein emerges. Metallothionein was isolated from the liver of carp and analyzed using High-Performance Liquid

Numerical modelling of the pump-to-signal relative intensity noise ...

Indian Academy of Sciences (India)

An accurate numerical model to investigate the pump-to-signal relative intensity noise (RIN) transfer in two-pump fibre optical parametric amplifiers (2-P FOPAs) for low modulation frequencies is presented. Compared to other models in the field, this model takes into account the fibre loss, pump depletion as well as the gain ...

PERANAN GAYA KEPEMIMPINAN YANG EFEKTIF DALAM UPAYA MENINGKATKAN SEMANGAT DAN KEGAIRAHAN KERJA KARYAWAN DI TOSERBA SINAR MAS SIDOARJO

Directory of Open Access Journals (Sweden)

Eddy Madiono Sutanto

2000-01-01

Full Text Available Leadership represents something that should be possessed by each leader of an organization. The effectiveness of a leader is determined by his ability to influence and direct the members of the organization. In order test the style of leadership which is effective at Toserba Sinar Mas in Sidoarjo, this research seeks to determine the relationship of leadership style with enthusiasm and excitement for work. In this study, it is found that the most effective leadership style is leadership which is adapted to the situation of the people being led. There is an indication that enthusiasm and excitement (measured by the level of absenteeism and worker turnover for work may decline as a result of unfavorable leadership. Abstract in Bahasa Indonesia : Kepemimpinan merupakan suatu hal yang seharusnya dimiliki oleh setiap pemimpin organisasi. Efektivitas seorang pemimpin ditentukan oleh kepiawaiannya mempengaruhi dan mengarahkan para anggotanya. Di dalam rangka untuk menguji gaya kepemimpinan yang efektif di Toserba Sinar Mas, Sidoarjo, maka penelitian ini dilakukan untuk membuktikan hubungan antara gaya kepemimpinan dengan semangat dan kegairahan kerja. Di dalam penelitian ini diungkapkan bahwa gaya kepemimpinan yang efektif adalah kepemimpinan yang disesuaikan dengan situasi dan kondisi dari orang-orang yang dipimpin. Indikasi turunnya semangat dan kegairahan kerja ditunjukkan dengan tingginya tingkat absensi dan perpindahan karyawan. Hal itu timbul sebagai akibat dari kepemimpinan yang tidak disenangi. Kata kunci: gaya kepemimpinan, semangat kerja, kegairahan kerja, tingkat absensi, tingkat perpindahan

Analysis of nonlinear behavior of loudspeakers using the instantaneous frequency

DEFF Research Database (Denmark)

Huang, Hai; Jacobsen, Finn

2003-01-01

on the Fourier transform. In this work, a new method using the instantaneous frequency is introduced for describing and characterizing loudspeaker nonlinearities. First, numerical integration is applied to simulate the nonlinearities of loudspeakers caused by two nonlinear parameters, force factor and stiffness...

Out-and-back {sup 13}C-{sup 13}C scalar transfers in protein resonance assignment by proton-detected solid-state NMR under ultra-fast MAS

Energy Technology Data Exchange (ETDEWEB)

Barbet-Massin, Emeline; Pell, Andrew J. [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France); Jaudzems, Kristaps [Latvian Institute of Organic Synthesis (Latvia); Franks, W. Trent; Retel, Joren S. [Leibniz-Institut fuer Molekulare Pharmakologie (Germany); Kotelovica, Svetlana; Akopjana, Inara; Tars, Kaspars [Biomedical Research and Study Center (Latvia); Emsley, Lyndon [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France); Oschkinat, Hartmut [Leibniz-Institut fuer Molekulare Pharmakologie (Germany); Lesage, Anne; Pintacuda, Guido, E-mail: guido.pintacuda@ens-lyon.fr [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France)

2013-08-15

We present here {sup 1}H-detected triple-resonance H/N/C experiments that incorporate CO-CA and CA-CB out-and-back scalar-transfer blocks optimized for robust resonance assignment in biosolids under ultra-fast magic-angle spinning (MAS). The first experiment, (H)(CO)CA(CO)NH, yields {sup 1}H-detected inter-residue correlations, in which we record the chemical shifts of the CA spins in the first indirect dimension while during the scalar-transfer delays the coherences are present only on the longer-lived CO spins. The second experiment, (H)(CA)CB(CA)NH, correlates the side-chain CB chemical shifts with the NH of the same residue. These high sensitivity experiments are demonstrated on both fully-protonated and 100 %-H{sup N} back-protonated perdeuterated microcrystalline samples of Acinetobacter phage 205 (AP205) capsids at 60 kHz MAS.

Agglomeration processes in carbonaceous dusty plasmas, experiments and numerical simulations

International Nuclear Information System (INIS)

Dap, S; Hugon, R; De Poucques, L; Bougdira, J; Lacroix, D; Patisson, F

2010-01-01

This paper deals with carbon dust agglomeration in radio frequency acetylene/argon plasma. Two studies, an experimental and a numerical one, were carried out to model dust formation mechanisms. Firstly, in situ transmission spectroscopy of dust clouds in the visible range was performed in order to observe the main features of the agglomeration process of the produced carbonaceous dust. Secondly, numerical simulation tools dedicated to understanding the achieved experiments were developed. A first model was used for the discretization of the continuous population balance equations that characterize the dust agglomeration process. The second model is based on a Monte Carlo ray-tracing code coupled to a Mie theory calculation of dust absorption and scattering parameters. These two simulation tools were used together in order to numerically predict the light transmissivity through a dusty plasma and make comparisons with experiments.

Transparency of Magnetized Plasma at Cyclotron Frequency; TOPICAL

International Nuclear Information System (INIS)

G. Shvets; J.S. Wurtele

2002-01-01

Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of the nonlocal plasma oscillation. The complexity of the plasma system results in an index of refraction at the cyclotron frequency that differs from unity. Lagrangian description was used to elucidate the physics and enable numerical simulation of the plasma transparency and control of group and phase velocity. This control naturally leads to applications for electromagnetic pulse compression in the plasma and electron/ion acceleration

Low-frequency 1/f noise in graphene devices

Science.gov (United States)

Balandin, Alexander A.

2013-08-01

Low-frequency noise with a spectral density that depends inversely on frequency has been observed in a wide variety of systems including current fluctuations in resistors, intensity fluctuations in music and signals in human cognition. In electronics, the phenomenon, which is known as 1/f noise, flicker noise or excess noise, hampers the operation of numerous devices and circuits, and can be a significant impediment to the development of practical applications from new materials. Graphene offers unique opportunities for studying 1/f noise because of its two-dimensional structure and widely tunable two-dimensional carrier concentration. The creation of practical graphene-based devices will also depend on our ability to understand and control the low-frequency noise in this material system. Here, the characteristic features of 1/f noise in graphene and few-layer graphene are reviewed, and the implications of such noise for the development of graphene-based electronics including high-frequency devices and sensors are examined.

Optically transparent frequency selective surfaces on flexible thin plastic substrates

Energy Technology Data Exchange (ETDEWEB)

Dewani, Aliya A., E-mail: a.ashraf@griffith.edu.au; O’Keefe, Steven G.; Thiel, David V.; Galehdar, Amir [School Of Electrical Engineering, Griffith University, Brisbane, 4111 (Australia)

2015-02-15

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

Optically transparent frequency selective surfaces on flexible thin plastic substrates

Directory of Open Access Journals (Sweden)

Aliya A. Dewani

2015-02-01

Full Text Available A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm, flexible transparent plastic substrate (relative permittivity 3.2. It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

Optically transparent frequency selective surfaces on flexible thin plastic substrates

Science.gov (United States)

Dewani, Aliya A.; O'Keefe, Steven G.; Thiel, David V.; Galehdar, Amir

2015-02-01

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

A lightweight low-frequency sound insulation membrane-type acoustic metamaterial

Directory of Open Access Journals (Sweden)

Kuan Lu

2016-02-01

Full Text Available A novel membrane-type acoustic metamaterial with a high sound transmission loss (STL at low frequencies (⩽500Hz was designed and the mechanisms were investigated by using negative mass density theory. This metamaterial’s structure is like a sandwich with a thin (thickness=0.25mm lightweight flexible rubber material within two layers of honeycomb cell plates. Negative mass density was demonstrated at frequencies below the first natural frequency, which results in the excellent low-frequency sound insulation. The effects of different structural parameters of the membrane on the sound-proofed performance at low frequencies were investigated by using finite element method (FEM. The numerical results show that, the STL can be modulated to higher value by changing the structural parameters, such as the membrane surface density, the unite cell film shape, and the membrane tension. The acoustic metamaterial proposed in this study could provide a potential application in the low-frequency noise insulation.

A lightweight low-frequency sound insulation membrane-type acoustic metamaterial

Science.gov (United States)

Lu, Kuan; Wu, Jiu Hui; Guan, Dong; Gao, Nansha; Jing, Li

2016-02-01

A novel membrane-type acoustic metamaterial with a high sound transmission loss (STL) at low frequencies (⩽500Hz) was designed and the mechanisms were investigated by using negative mass density theory. This metamaterial's structure is like a sandwich with a thin (thickness=0.25mm) lightweight flexible rubber material within two layers of honeycomb cell plates. Negative mass density was demonstrated at frequencies below the first natural frequency, which results in the excellent low-frequency sound insulation. The effects of different structural parameters of the membrane on the sound-proofed performance at low frequencies were investigated by using finite element method (FEM). The numerical results show that, the STL can be modulated to higher value by changing the structural parameters, such as the membrane surface density, the unite cell film shape, and the membrane tension. The acoustic metamaterial proposed in this study could provide a potential application in the low-frequency noise insulation.

Sensitivity analysis of the stiffness between the frame structure and the frequency and vibration mode

Science.gov (United States)

Chen, Wenyuan

2018-03-01

The modal parameters such as natural frequency and vibration mode of the frame structure of the layer stiffness sensitivity is inconsistent. This article focuses on the theoretical derivation of the frequency and mode of the frame structure layer stiffness of the first-order sensitivity. The numerical examples show that the frame structure of layer stiffness higher than with the first order sensitivity vibration frequency.

Molybdenum modified phosphate glasses studied by 31P MAS NMR and Raman spectroscopy.

Science.gov (United States)

Szumera, Magdalena

2015-02-25

Glasses have been synthesized in the system P2O5-SiO2-K2O-MgO-CaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40 g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and (31)P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]-O-P and/or Mo[MoO4/MoO6]-O-Si bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations. Copyright © 2014 Elsevier B.V. All rights reserved.

Alfven frequency modes and global Alfven eigenmodes

International Nuclear Information System (INIS)

Villard, L.; Vaclavik, J.

1996-07-01

The spectrum of n=0 Alfven modes is calculated analytically and numerically in cylindrical and toroidal geometries. It includes Global Alfven Eigenmodes (GAE) and Surface Modes (SM) of the fast magnetoacoustic wave. These modes are not induced by toroidicity. The n=0 GAEs owe their existence to the shear. The frequency spacing between different radial and poloidal modes and the correlation of eigenfrequencies with changes in the edge density are examined and found in complete agreement with experimental observations of what has been named the 'Alfven Frequency Mode' (AFM) so far. Although the eigenfrequency is related to the edge density, the n=0 GAE (AFM) is not necessarily edge-localized. (author) figs., tabs., refs

Low-frequency computational electromagnetics for antenna analysis

Energy Technology Data Exchange (ETDEWEB)

Miller, E.K. (Los Alamos National Lab., NM (USA)); Burke, G.J. (Lawrence Livermore National Lab., CA (USA))

1991-01-01

An overview of low-frequency, computational methods for modeling the electromagnetic characteristics of antennas is presented here. The article presents a brief analytical background, and summarizes the essential ingredients of the method of moments, for numerically solving low-frequency antenna problems. Some extensions to the basic models of perfectly conducting objects in free space are also summarized, followed by a consideration of some of the same computational issues that affect model accuracy, efficiency and utility. A variety of representative computations are then presented to illustrate various modeling aspects and capabilities that are currently available. A fairly extensive bibliography is included to suggest further reference material to the reader. 90 refs., 27 figs.

Sampling methods for low-frequency electromagnetic imaging

International Nuclear Information System (INIS)

Gebauer, Bastian; Hanke, Martin; Schneider, Christoph

2008-01-01

For the detection of hidden objects by low-frequency electromagnetic imaging the linear sampling method works remarkably well despite the fact that the rigorous mathematical justification is still incomplete. In this work, we give an explanation for this good performance by showing that in the low-frequency limit the measurement operator fulfils the assumptions for the fully justified variant of the linear sampling method, the so-called factorization method. We also show how the method has to be modified in the physically relevant case of electromagnetic imaging with divergence-free currents. We present numerical results to illustrate our findings, and to show that similar performance can be expected for the case of conducting objects and layered backgrounds

A theoretical response of the electrostatic parallel plate to constant and low-frequency accelerations

International Nuclear Information System (INIS)

Lee, Ki Bang

2009-01-01

A theoretical response of an electrostatic gap-closing actuator based on parallel plates to constant and low-frequency accelerations has been derived as a function of the applied acceleration and voltage. The nonlinear equation of motion is obtained in a dimensionless form from the fact that the inertial and damping forces are neglected at a frequency much less than the resonant frequency of the parallel plate, and thereafter the nonlinear equation is solved for the stable inter-plate gap at the acceleration and voltage. From the derived solution, the pull-in acceleration is obtained as a function of the applied voltage, and the pull-in voltage is also expressed as a function of the acceleration. The closed-form solution is validated by comparison with a numerical solution. The theoretical solution is in excellent agreement with the numerical results when the actuator is exposed to a constant acceleration as well as a low-frequency acceleration. The theoretical solution and pull-in acceleration and voltage thus provide guidance to prescribe operational constraints for devices that use the parallel plate actuator and to predict the response of the electrostatic gap-closing parallel plates to constant and low-frequency acceleration

1H-detected MAS solid-state NMR experiments enable the simultaneous mapping of rigid and dynamic domains of membrane proteins

Science.gov (United States)

Gopinath, T.; Nelson, Sarah E. D.; Veglia, Gianluigi

2017-12-01

Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is emerging as a unique method for the atomic resolution structure determination of native membrane proteins in lipid bilayers. Although 13C-detected ssNMR experiments continue to play a major role, recent technological developments have made it possible to carry out 1H-detected experiments, boosting both sensitivity and resolution. Here, we describe a new set of 1H-detected hybrid pulse sequences that combine through-bond and through-space correlation elements into single experiments, enabling the simultaneous detection of rigid and dynamic domains of membrane proteins. As proof-of-principle, we applied these new pulse sequences to the membrane protein phospholamban (PLN) reconstituted in lipid bilayers under moderate MAS conditions. The cross-polarization (CP) based elements enabled the detection of the relatively immobile residues of PLN in the transmembrane domain using through-space correlations; whereas the most dynamic region, which is in equilibrium between folded and unfolded states, was mapped by through-bond INEPT-based elements. These new 1H-detected experiments will enable one to detect not only the most populated (ground) states of biomacromolecules, but also sparsely populated high-energy (excited) states for a complete characterization of protein free energy landscapes.

The Real-time Frequency Spectrum Analysis of Neutron Pulse Signal Series

International Nuclear Information System (INIS)

Tang Yuelin; Ren Yong; Wei Biao; Feng Peng; Mi Deling; Pan Yingjun; Li Jiansheng; Ye Cenming

2009-01-01

The frequency spectrum analysis of neutron pulse signal is a very important method in nuclear stochastic signal processing Focused on the special '0' and '1' of neutron pulse signal series, this paper proposes new rotation-table and realizes a real-time frequency spectrum algorithm under 1G Hz sample rate based on PC with add, address and SSE. The numerical experimental results show that under the count rate of 3X10 6 s -1 , this algorithm is superior to FFTW in time-consumption and can meet the real-time requirement of frequency spectrum analysis. (authors)

Rounding behavior in the reporting of headache frequency complicates headache chronification research.

Science.gov (United States)

Houle, Timothy T; Turner, Dana P; Houle, Thomas A; Smitherman, Todd A; Martin, Vincent; Penzien, Donald B; Lipton, Richard B

2013-06-01

To characterize the extent of measurement error arising from rounding in headache frequency reporting (days per month) in a population sample of headache sufferers. When reporting numerical health information, individuals tend to round their estimates. The tendency to round to the nearest 5 days when reporting headache frequency can distort distributions and engender unreliability in frequency estimates in both clinical and research contexts. This secondary analysis of the 2005 American Migraine Prevalence and Prevention study survey characterized the population distribution of 30-day headache frequency among community headache sufferers and determined the extent of numerical rounding ("heaping") in self-reported data. Headache frequency distributions (days per month) were examined using a simplified version of Wang and Heitjan's approach to heaping to estimate the probability that headache sufferers round to a multiple of 5 when providing frequency reports. Multiple imputation was used to estimate a theoretical "true" headache frequency. Of the 24,000 surveys, headache frequency data were available for 15,976 respondents diagnosed with migraine (68.6%), probable migraine (8.3%), or episodic tension-type headache (10.0%); the remainder had other headache types. The mean number of headaches days/month was 3.7 (standard deviation = 5.6). Examination of the distribution of headache frequency reports revealed a disproportionate number of responses centered on multiples of 5 days. The odds that headache frequency was rounded to 5 increased by 24% with each 1-day increase in headache frequency (odds ratio: 1.24, 95% confidence interval: 1.23 to 1.25), indicating that heaping occurs most commonly at higher headache frequencies. Women were more likely to round than men, and rounding decreased with increasing age and increased with symptoms of depression. Because of the coarsening induced by rounding, caution should be used when distinguishing between episodic and chronic

Dynamic load synthesis for shock numerical simulation in space structure design

Science.gov (United States)

Monti, Riccardo; Gasbarri, Paolo

2017-08-01

Pyroshock loads are the most stressing environments that a space equipment experiences during its operating life from a mechanical point of view. In general, the mechanical designer considers the pyroshock analysis as a very demanding constraint. Unfortunately, due to the non-linear behaviour of the structure under such loads, only the experimental tests can demonstrate if it is able to withstand these dynamic loads. By taking all the previous considerations into account, some preliminary information about the design correctness could be done by performing ;ad-hoc; numerical simulations, for example via commercial finite element software (i.e. MSC Nastran). Usually these numerical tools face the shock solution in two ways: 1) a direct mode, by using a time dependent enforcement and by evaluating the time-response and space-response as well as the internal forces; 2) a modal basis approach, by considering a frequency dependent load and of course by evaluating internal forces in the frequency domain. This paper has the main aim to develop a numerical tool to synthetize the time dependent enforcement based on deterministic and/or genetic algorithm optimisers. In particular starting from a specified spectrum in terms of SRS (Shock Response Spectrum) a time dependent discrete function, typically an acceleration profile, will be obtained to force the equipment by simulating the shock event. The synthetizing time and the interface with standards numerical codes will be two of the main topics dealt with in the paper. In addition a congruity and consistency methodology will be presented to ensure that the identified time dependent loads fully match the specified spectrum.

Frequency-dependent Alfvén-wave Propagation in the Solar Wind: Onset and Suppression of Parametric Decay Instability

Science.gov (United States)

Shoda, Munehito; Yokoyama, Takaaki; Suzuki, Takeru K.

2018-06-01

Using numerical simulations we investigate the onset and suppression of parametric decay instability (PDI) in the solar wind, focusing on the suppression effect by the wind acceleration and expansion. Wave propagation and dissipation from the coronal base to 1 au is solved numerically in a self-consistent manner; we take into account the feedback of wave energy and pressure in the background. Monochromatic waves with various injection frequencies, f 0, are injected to discuss the suppression of PDI, while broadband waves are applied to compare the numerical results with observation. We find that high-frequency ({f}0≳ {10}-3 {Hz}) Alfvén waves are subject to PDI. Meanwhile, the maximum growth rate of the PDI of low-frequency ({f}0≲ {10}-4 {Hz}) Alfvén waves becomes negative due to acceleration and expansion effects. Medium-frequency ({f}0≈ {10}-3.5 {Hz}) Alfvén waves have a positive growth rate but do not show the signature of PDI up to 1 au because the growth rate is too small. The medium-frequency waves experience neither PDI nor reflection so they propagate through the solar wind most efficiently. The solar wind is shown to possess a frequency-filtering mechanism with respect to Alfvén waves. The simulations with broadband waves indicate that the observed trend of the density fluctuation is well explained by the evolution of PDI while the observed cross-helicity evolution is in agreement with low-frequency wave propagation.

Images of the plant kingdom in the Mamluk encyclopedia Masālik al-abṣār by Ibn Faḍl Allāh al-‘Umarī (d. 1349)

OpenAIRE

Francesca Bellino

2016-01-01

This article aims at analyzing the representation of the plant kingdom in the Masālik al-abṣār fī mamālik al-amṣār, an Arabic encyclopaedia written by one the leading scholar of the Mamluk period, Šihāb al-Dīn Ibn Faḍl Allāh al-‘Umarī (1301-1349). The first part of the article offers an insight into the work of al-‘Umarī by presenting it in the framework of the encyclopaedic activities that characterize the fourteenth century. It also analyzes a number of special features of the Masālik al-ab...

Frequency Shifts of Micro and Nano Cantilever Beam Resonators Due to Added Masses

KAUST Repository

Bouchaala, Adam M.

2016-03-21

We present analytical and numerical techniques to accurately calculate the shifts in the natural frequencies of electrically actuated micro and nano (carbon nanotubes (CNTs)) cantilever beams implemented as resonant sensors for mass detection of biological entities, particularly Escherichia coli (E. coli) and prostate specific antigen (PSA) cells. The beams are modeled as Euler-Bernoulli beams, including the nonlinear electrostatic forces and the added biological cells, which are modeled as discrete point masses. The frequency shifts due to the added masses of the cells are calculated for the fundamental and higher-order modes of vibrations. Analytical expressions of the natural frequency shifts under a direct current (DC) voltage and an added mass have been developed using perturbation techniques and the Galerkin approximation. Numerical techniques are also used to calculate the frequency shifts and compared with the analytical technique. We found that a hybrid approach that relies on the analytical perturbation expression and the Galerkin procedure for calculating accurately the static behavior presents the most computationally efficient approach. We found that using higher-order modes of vibration of micro-electro-mechanical-system (MEMS) beams or miniaturizing the sizes of the beams to nanoscale leads to significant improved frequency shifts, and thus increased sensitivities. © 2016 by ASME.

A numerical study on acoustic behavior in gas turbine combustor with acoustic resonator

International Nuclear Information System (INIS)

Park, I Sun; Sohn, Chae Hoon

2005-01-01

Acoustic behavior in gas turbine combustor with acoustic resonator is investigated numerically by adopting linear acoustic analysis. Helmholtz-type resonator is employed as acoustic resonator to suppress acoustic instability passively. The tuning frequency of acoustic resonator is adjusted by varying its length. Through harmonic analysis, acoustic-pressure responses of chamber to acoustic excitation are obtained and the resonant acoustic modes are identified. Acoustic damping effect of acoustic resonator is quantified by damping factor. As the tuning frequency of acoustic resonator approaches the target frequency of the resonant mode to be suppressed, mode split from the original resonant mode to lower and upper modes appears and thereby complex patterns of acoustic responses show up. Considering mode split and damping effect as a function of tuning frequency, it is desirable to make acoustic resonator tuned to broad-band frequencies near the maximum frequency of those of the possible upper modes

A lightweight vibro-acoustic metamaterial demonstrator: Numerical and experimental investigation

Science.gov (United States)

Claeys, C.; Deckers, E.; Pluymers, B.; Desmet, W.

2016-03-01

In recent years metamaterials gained a lot of attention due to their superior noise and vibration insulation properties, be it at least in some targeted and tuneable frequency ranges, referred to as stopbands. These are frequency zones for which free wave propagation is prevented throughout the metamaterial, resulting in frequency zones of pronounced wave attenuation. Metamaterials are achieved due to addition of an, often periodic, grid of resonant structures to a host material or structure. The interaction between resonant inclusions and host structure can lead to a performance which is superior to the ones of any of the constituent materials. A key element in this concept is that waves can be affected by incorporating structural resonant elements of sub-wavelength sizes, i.e. features that are actually smaller than the wavelength of the waves to be affected. This paves the way towards compact and light vibro-acoustic solutions in the lower frequency ranges. This paper discusses the numerical design and experimental validation of acoustic insulation based on the concept of metamaterials: a hollow core periodic sandwich structure with added local resonant structures. In order to investigate the sensitivity to specific parameters in the metamaterial design and the robustness of the design, a set of variations on the nominal design are investigated. The stop bands are numerically predicted through unit cell modelling after which a full vibro-acoustic finite element model is applied to predict the insertion loss of the demonstrator. The results of these analyses are compared with measurements; both indicate that this metamaterials concept can be applied to combine light weight, compact volume and good acoustic behaviour.

Observation of immobile regions in natural rubber at ambient temperature by solid-state C-13 CP/MAS NMR spectroscopy

DEFF Research Database (Denmark)

Larsen, F.H.; Rasmussen, T.; Pedersen, Walther Batsberg

1999-01-01

Employing C-13 CP/MAS NMR spectroscopy, the existence of immobile regions in natural rubber (cis-1,4-polyisoprene) corresponding to a few percent of the monomer units has been detected at ambient temperature. For synthetic rubbers no immobile regions have been detected at all. Applying different...... physical and chemical treatments to natural rubber it is shown that mastication, gamma-irradiation, and increasing the temperature, slightly above the ambient, reduce the amount of immobile regions. (C) 1999 Elsevier Science Ltd. All rights reserved....

Entrenamiento y fisiología del ejercicio en la pubertad : Análisis de las creencias actuales mas frecuentes

OpenAIRE

Mirco, Gustavo Ariel

2013-01-01

El presente trabajo forma parte de la especialización en fisiología del ejercicio de la Universidad Nacional de La Plata, Argentina. En este estudio se pudo comprobar la existencia de diversas creencias en cuanto a las prácticas de entrenamientos físico-deportivos en edades puberales. En primer lugar se seleccionaron algunas de las creencias consideradas mas relevantes en cuanto al impacto que pudieran ocasionar en los jóvenes practicantes. Posteriormente se confecciono un instrumento de reco...

Jump resonant frequency islands in nonlinear feedback control systems

Science.gov (United States)

Koenigsberg, W. D.; Dunn, J. C.

1975-01-01

A new type of jump resonance is predicted and observed in certain nonlinear feedback control systems. The new jump resonance characteristic is described as a 'frequency island' due to the fact that a portion of the input-output transfer characteristic is disjoint from the main body. The presence of such frequency islands was predicted by using a sinusoidal describing function characterization of the dynamics of an inertial gyro employing nonlinear ternary rebalance logic. While the general conditions under which such islands are possible has not been examined, a numerical approach is presented which can aid in establishing their presence. The existence of the frequency islands predicted for the ternary rebalanced gyro was confirmed by simulating the nonlinear system and measuring the transfer function.

Numerical research of a 2D axial symmetry hybrid model for the radio-frequency ion thruster

Science.gov (United States)

Chenchen, WU; Xinfeng, SUN; Zuo, GU; Yanhui, JIA

2018-04-01

Since the high efficiency discharge is critical to the radio-frequency ion thruster (RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy correction of the electron energy distribution function (EEDF) are applied to the analysis of the RIT discharge. In the meantime, the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region. The beam current simulation results, with the hybrid model, agree well with the experimental results, and the error is lower than 11%, which shows the validity of the model. The further study shows there is an optimal ratio for the radio-frequency (RF) power and the beam current extraction power under the fixed RIT configuration. And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold (about 87 W). As the input parameters of the hybrid model are all the design values, it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.

Numerical Simulation of the Oscillations in a Mixer: An Internal Aeroacoustic Feedback System

Science.gov (United States)

Jorgenson, Philip C. E.; Loh, Ching Y.

2004-01-01

The space-time conservation element and solution element method is employed to numerically study the acoustic feedback system in a high temperature, high speed wind tunnel mixer. The computation captures the self-sustained feedback loop between reflecting Mach waves and the shear layer. This feedback loop results in violent instabilities that are suspected of causing damage to some tunnel components. The computed frequency is in good agreement with the available experimental data. The physical phenomena are explained based on the numerical results.

Numerical Modeling of a Wave Energy Point Absorber

DEFF Research Database (Denmark)

Hernandez, Lorenzo Banos; Frigaard, Peter; Kirkegaard, Poul Henning

2009-01-01

The present study deals with numerical modelling of the Wave Star Energy WSE device. Hereby, linear potential theory is applied via a BEM code on the wave hydrodynamics exciting the floaters. Time and frequency domain solutions of the floater response are determined for regular and irregular seas....... Furthermore, these results are used to estimate the power and the energy absorbed by a single oscillating floater. Finally, a latching control strategy is analysed in open-loop configuration for energy maximization....

Thermal heat-balance mode flow-to-frequency converter

Science.gov (United States)

Pawlowski, Eligiusz

2016-11-01

This paper presents new type of thermal flow converter with the pulse frequency output. The integrating properties of the temperature sensor have been used, which allowed for realization of pulse frequency modulator with thermal feedback loop, stabilizing temperature of sensor placed in the flowing medium. The system assures balancing of heat amount supplied in impulses to the sensor and heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output impulses is proportional to the heat transfer coefficient from sensor to environment. According to the King's law, the frequency of those impulses is a function of medium flow velocity around the sensor. The special feature of presented solution is total integration of thermal sensor with the measurement signal conditioning system. Sensor and conditioning system are not the separate elements of the measurement circuit, but constitute a whole in form of thermal heat-balance mode flow-to-frequency converter. The advantage of such system is easiness of converting the frequency signal to the digital form, without using any additional analogue-to-digital converters. The frequency signal from the converter may be directly connected to the microprocessor input, which with use of standard built-in counters may convert the frequency into numerical value of high precision. Moreover, the frequency signal has higher resistance to interference than the voltage signal and may be transmitted to remote locations without the information loss.

Klientu attiecību pārvaldes sistēmas ieviešana IT uzņēmumā un pielāgošana tā biznesa vajadzībām

OpenAIRE

Šmitenbergs, Oskars

2006-01-01

Bakalaura darbs „Klientu attiecību pārvaldes sistēmas ieviešana IT uzņēmumā un pielāgošana tā biznesa vajadzībām” ir sistēmas Microsoft Dynamics™ CRM 3.0 ieviešanas procesa apraksts IT uzņēmumā SIA „UNITREE”. Darbs sniedz ieskatu sistēmas ieviešanas nepieciešamības cēloņos vidēja lieluma un lielos uzņēmumos. Kā viena no problēmu cēloņu novēršanas iespējām tiek piedāvāta Microsoft Dynamics™ CRM 3.0 ieviešana uzņēmumā, tāpēc darbā galvenokārt tiek apskatīta biznesa pārvaldības iespējas, izmanto...

Antenatal betamethasone attenuates the angiotensin-(1-7)-Mas receptor-nitric oxide axis in isolated proximal tubule cells.

Science.gov (United States)

Su, Yixin; Bi, Jianli; Pulgar, Victor M; Chappell, Mark C; Rose, James C

2017-06-01

We previously reported a sex-specific effect of antenatal treatment with betamethasone (Beta) on sodium (Na + ) excretion in adult sheep whereby treated males but not females had an attenuated natriuretic response to angiotensin-(1-7) [Ang-(1-7)]. The present study determined the Na + uptake and nitric oxide (NO) response to low-dose Ang-(1-7) (1 pM) in renal proximal tubule cells (RPTC) from adult male and female sheep antenatally exposed to Beta or vehicle. Data were expressed as percentage of basal uptake or area under the curve for Na + or percentage of control for NO. Male Beta RPTC exhibited greater Na + uptake than male vehicle cells (433 ± 28 vs. 330 ± 26%; P 0.05). Ang-(1-7) significantly inhibited Na + uptake in RPTC from vehicle male (214 ± 11%) and from both vehicle (190 ± 14%) and Beta (209 ± 11%) females but failed to attenuate Na + uptake in Beta male cells. Beta exposure also abolished stimulation of NO by Ang-(1-7) in male but not female RPTC. Both the Na + and NO responses to Ang-(1-7) were blocked by Mas receptor antagonist d-Ala 7 -Ang-(1-7). We conclude that the tubular Ang-(1-7)-Mas-NO pathway is attenuated in males and not females by antenatal Beta exposure. Moreover, since primary cultures of RPTC retain both the sex and Beta-induced phenotype of the adult kidney in vivo they appear to be an appropriate cell model to examine the effects of fetal programming on Na + handling by the renal tubules. Copyright © 2017 the American Physiological Society.

Low frequency electric and magnetic fields

Science.gov (United States)

Spaniol, Craig

1989-01-01

Following preliminary investigations of the low frequency electric and magnetic fields that may exists in the Earth-ionospheric cavity, measurements were taken with state-of-the art spectrum analyzers. As a follow up to this activity, an investigation was initiated to determine sources and values for possible low frequency signal that would appear in the cavity. The lowest cavity resonance is estimated at about 8 Hz, but lower frequencies may be an important component of our electromagnetic environment. The potential field frequencies produced by the electron were investigated by a classical model that included possible cross coupling of the electric and gravitation fields. During this work, an interesting relationship was found that related the high frequency charge field with the extremely low frequency of the gravitation field. The results of numerical calculations were surprisingly accurate and this area of investigation is continuing. The work toward continued development of a standardized monitoring facility is continuing with the potential of installing the prototype at West Virginia State College early in 1990. This installation would be capable of real time monitoring of ELF signals in the Earth-ionoshpere cavity and would provide some directional information. A high gain, low noise, 1/f frequency corrected preamplifier was designed and tested for the ferrite core magnetic sensor. The potential application of a super conducting sensor for the ELF magnetic field detection is under investigation. It is hoped that a fully operational monitoring network could pinpoint the location of ELF signal sources and provide new information on where these signals originate and what causes them, assuming that they are natural in origin.

Validation of Vibro-Impact Force Models by Numerical Simulation, Perturbation Methods and Experiments

DEFF Research Database (Denmark)

de Souza Reboucas, Geraldo Francisco; Santos, Ilmar; Thomsen, Jon Juel

2017-01-01

The frequency response of a single degree of freedom vibro-impact oscillator is analyzed using Harmonic Linearization, Averaging and Numeric Simulation, considering three different impact force models: one given by a piecewise-linear function (Kelvin-Voigt model), another by a high-order power...

Experimental validation of vibro-impact force models using numeric simulation and perturbation methods

DEFF Research Database (Denmark)

de Souza Reboucas, Geraldo Francisco; Santos, Ilmar; Thomsen, Jon Juel

2017-01-01

The frequency response of a single-degree of freedom vibro-impact oscillator is analysed using Harmonic Linearization, Averaging and Numeric Simulations considering two different impact force models, one given by a piecewise-linear function and other by a high-order polynomial. Experimental...

Nonlinear analysis for dual-frequency concurrent energy harvesting

Science.gov (United States)

Yan, Zhimiao; Lei, Hong; Tan, Ting; Sun, Weipeng; Huang, Wenhu

2018-05-01

The dual-frequency responses of the hybrid energy harvester undergoing the base excitation and galloping were analyzed numerically. In this work, an approximate dual-frequency analytical method is proposed for the nonlinear analysis of such a system. To obtain the approximate analytical solutions of the full coupled distributed-parameter model, the forcing interactions is first neglected. Then, the electromechanical decoupled governing equation is developed using the equivalent structure method. The hybrid mechanical response is finally separated to be the self-excited and forced responses for deriving the analytical solutions, which are confirmed by the numerical simulations of the full coupled model. The forced response has great impacts on the self-excited response. The boundary of Hopf bifurcation is analytically determined by the onset wind speed to galloping, which is linearly increased by the electrical damping. Quenching phenomenon appears when the increasing base excitation suppresses the galloping. The theoretical quenching boundary depends on the forced mode velocity. The quenching region increases with the base acceleration and electrical damping, but decreases with the wind speed. Superior to the base-excitation-alone case, the existence of the aerodynamic force protects the hybrid energy harvester at resonance from damages caused by the excessive large displacement. From the view of the harvested power, the hybrid system surpasses the base-excitation-alone system or the galloping-alone system. This study advances our knowledge on intrinsic nonlinear dynamics of the dual-frequency energy harvesting system by taking advantage of the analytical solutions.

Investigation of two-frequency Paul traps for antihydrogen production

Energy Technology Data Exchange (ETDEWEB)

Leefer, Nathan; Krimmel, Kai, E-mail: kkrimmel@students.uni-mainz.de [Helmholtz-Institut Mainz (Germany); Bertsche, William [University of Manchester (United Kingdom); Budker, Dmitry [Helmholtz-Institut Mainz (Germany); Fajans, Joel [University of California at Berkeley, Department of Physics (United States); Folman, Ron [Ben-Gurion University of the Negev, Department of Physics (Israel); Häffner, Hartmut [University of California at Berkeley, Department of Physics (United States); Schmidt-Kaler, Ferdinand [Helmholtz-Institut Mainz (Germany)

2017-11-15

Radio-frequency (rf) Paul traps operated with multifrequency rf trapping potentials provide the ability to independently confine charged particle species with widely different charge-to-mass ratios. In particular, these traps may find use in the field of antihydrogen recombination, allowing antiproton and positron clouds to be trapped and confined in the same volume without the use of large superconducting magnets. We explore the stability regions of two-frequency Paul traps and perform numerical simulations of small samples of multispecies charged-particle mixtures of up to twelve particles that indicate the promise of these traps for antihydrogen recombination.

Adding real data to detect emotions by means of smart resource artifacts in MAS

Directory of Open Access Journals (Sweden)

Jaime RINCÓN

2016-12-01

Full Text Available This article proposes an application of a social emotional model, which allows to extract, analyse, represent and manage the social emotion of a group of entities. Specifically, the application is based on how music can influence in a positive or negative way over emotional states. The proposed approach employs the JaCalIVE framework, which facilitates the development of this kind of environments. A physical device called smart resource offers to agents processed sensor data as a service. So that, agents obtain real data from a smart resource. MAS uses the smart resource as an artifact by means of a specific communications protocol. The framework includes a design method and a physical simulator. In this way, the social emotional model allows the creation of simulations over JaCalIVE, in which the emotional states are used in the decision-making of the agents.

1H CSA parameters by ultrafast MAS NMR: Measurement and applications to structure refinement.

Science.gov (United States)

Miah, Habeeba K; Cresswell, Rosalie; Iuga, Dinu; Titman, Jeremy J

2017-10-01

A 1 H anisotropic-isotropic chemical shift correlation experiment which employs symmetry-based recoupling sequences to reintroduce the chemical shift anisotropy in ν 1 and ultrafast MAS to resolve 1 H sites in ν 2 is described. This experiment is used to measure 1 H shift parameters for L-ascorbic acid, a compound with a relatively complex hydrogen-bonding network in the solid. The 1 H CSAs of hydrogen-bonded sites with resolved isotropic shifts can be extracted directly from the recoupled lineshapes. In combination with DFT calculations, hydrogen positions in crystal structures obtained from X-ray and neutron diffraction are refined by comparison with simulations of the full two-dimensional NMR spectrum. The improved resolution afforded by the second dimension allows even unresolved hydrogen-bonded sites 1 H to be assigned and their shift parameters to be obtained. Copyright © 2017 Elsevier Inc. All rights reserved.

Direct numerical simulations of nucleate boiling flows of binary mixtures

International Nuclear Information System (INIS)

Didier Jamet; Celia Fouillet

2005-01-01

Full text of publication follows: Better understand the origin and characteristics of boiling crisis is still a scientific challenge despite many years of valuable studies. One of the reasons why boiling crisis is so difficult to understand is that local and coupled physical phenomena are believed to play a key role in the trigger of instabilities which lead to the dry out of large portions of the heated solid phase. Nucleate boiling of a single bubble is fairly well understood compared to boiling crisis. Therefore, the numerical simulation of a single bubble growth during nucleate boiling is a good candidate to evaluate the capabilities of a numerical method to deal with complex liquid-vapor phenomena with phase-change and eventually to tackle the boiling crisis problem. In this paper, we present results of direct numerical simulations of nucleate boiling. The numerical method used is the second gradient method, which is a diffuse interface method dedicated to liquid vapor flows with phase-change. This study is not intended to provide quantitative results, partly because all the simulations are two-dimensional. However, particular attention is paid to the influence of some parameters on the main features of nucleate boiling, i.e. the radius of departure and the frequency of detachment of bubbles. In particular, we show that, as the contact angle increases, the radius of departure increases whereas the frequency of detachment decreases. Moreover, the influence of the existence of quasi non-condensable gas is studied. Numerical results show an important decrease of the heat exchange coefficient when a small amount of a quasi non-condensable gas is added to the pure liquid-vapor water system. This result is in agreement with experimental observations. Beyond these qualitative results, this numerical study allows to get insight into some important physical phenomena and to confirm that during nucleate boiling, large scale quantities are influenced by small scale

Sub-wavelength imaging at radio frequency

International Nuclear Information System (INIS)

Wiltshire, M C K; Pendry, J B; Hajnal, J V

2006-01-01

A slab of material with a negative permeability can act as a super-lens for magnetic fields and generate images with a sub-wavelength resolution. We have constructed an effective medium using a metamaterial with negative permeability in the region of 24 MHz, and used this to form images in free space of radio frequency magnetic sources. Measurements of these images show that a resolution of approximately λ/64 has been achieved, consistent with both analytical and numerical predictions. (letter to the editor)

Uso del FitoMas-E® como atenuante del estrés salino (NaCl durante la emergencia y crecimiento inicial de Ocimum basilicum L.

Directory of Open Access Journals (Sweden)

D. Batista-Sánchez

2015-01-01

Full Text Available El uso de bioestimulantes vegetales estimula la emergencia y el crecimiento vegetal debido a que están compuestos por sustancias naturales como carbohidratos, péptidos de bajo peso molecular y aminoácidos, activadores de las funciones fisiológicas de las plantas, por lo que su aplicación permite un mejor aprovechamiento de los nutrientes y representa una opción para enfrentar problemas de estrés abiótico por salinidad. El objetivo de este estudio fue determinar el efecto del bioestimulante FitoMas-E® derivado de la caña de azúcar como atenuante de la salinidad en la emergencia y el crecimiento de plántulas de variedades de albahaca (Ocimum basilicum L. con respuesta diferencial al estrés por salinidad. Tres variedades de albahaca: Napoletano, Emily y Nufar se sometieron a cuatro concentraciones de NaCl (0, 50, 100 y 150 mM y cuatro dosis de FitoMas-E® (0, 0.5, 1.0 y 1.5 mL L-1 en un diseño completamente al azar con arreglo factorial con cuatro repeticiones. El trabajo se desarrolló en una estructura de malla sombra y las variables que se midieron fueron: porcentaje y tasa de emergencia, longitud de radícula, altura de la plántula, biomasa fresca y seca de radícula y de parte aérea. Los resultados evidenciaron que en condiciones de estrés salino (NaCl de moderado a severo, las variables disminuyeron significativamente. Largo de raíz, altura de planta y biomasa seca de raíz en 150 mM de NaCl fueron las más afectadas. Se observó que cuando se aplicó FitoMas-E® las plantas incrementaron significativamente sus valores en las variables, largo de raíz 32% y altura de planta 41%, lo que revela el efecto estimulante del FitoMas-E®, siendo 0.5 mL L-1 la dosis estimulante para la variedad Napoletano y 1.0 mL L-1 para la variedad Emily, aún y cuando se encontraban en condiciones de estrés salino hasta 100 mM de NaCl. Para la concentración de 150 mM se evidenció una afectación extrema para las variedades Emily y Nufar.

Analysis and Correction of Diffraction Effect on the B/A Measurement at High Frequencies

Science.gov (United States)

Zhang, Dong; Gong, Xiu-Fen; Liu, Xiao-Zhou; Kushibiki, Jun-ichi; Nishino, Hideo

2004-01-01

A numerical method is developed to analyse and to correct the diffraction effect in the measurement of acoustic nonlinearity parameter B/A at high frequencies. By using the KZK nonlinear equation and the superposition approach of Gaussian beams, an analytical model is derived to describe the second harmonic generation through multi-layer medium SiO2/liquid specimen/SiO2. Frequency dependence of the nonlinear characterization curve for water in 110-155 MHz is numerically and experimentally investigated. With the measured dip position and the new model, values of B/A for water are evaluated. The results show that the present method can effectively correct the diffraction effect in the measurement.

Radio-frequency ion deflector for mass separation

Energy Technology Data Exchange (ETDEWEB)

Schlösser, Magnus, E-mail: magnus.schloesser@googlemail.com; Rudnev, Vitaly; Ureña, Ángel González, E-mail: laseres@pluri.ucm.es [Unidad de Láseres y Haces Moleculares, Instituto Plurisdisciplinar, Universidad Complutense de Madrid, Madrid 28040 (Spain)

2015-10-15

Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

Finite-Difference Frequency-Domain Method in Nanophotonics

DEFF Research Database (Denmark)

Ivinskaya, Aliaksandra

Optics and photonics are exciting, rapidly developing fields building their success largely on use of more and more elaborate artificially made, nanostructured materials. To further advance our understanding of light-matter interactions in these complicated artificial media, numerical modeling...... is often indispensable. This thesis presents the development of rigorous finite-difference method, a very general tool to solve Maxwell’s equations in arbitrary geometries in three dimensions, with an emphasis on the frequency-domain formulation. Enhanced performance of the perfectly matched layers...... is obtained through free space squeezing technique, and nonuniform orthogonal grids are built to greatly improve the accuracy of simulations of highly heterogeneous nanostructures. Examples of the use of the finite-difference frequency-domain method in this thesis range from simulating localized modes...

A general model and numerical method for multiconductor systems in frequency domain

Energy Technology Data Exchange (ETDEWEB)

Jonas, F. [Swedish Transmission Research Inst., Ludvika (Sweden); Varju, G. [Technical Univ. of Budapest (Hungary). Dept. of Electric Power Systems

1995-12-01

A general multi-conductor model is described in this article. It is based on the distributed line parameter simulation with acceptance of non-homogeneous line sections, discrete and distributed sources, complex discrete elements of any kind at any point. Every parameter and element can be non-linear. The model and the software implementation has successfully been used for solution of different frequency domain problems, e.g. harmonic penetration in unbalanced power networks, railway circuits with auto- or booster transformers, telecommunication circuits. The results of a number of calculated cases have been verified by field tests. An application example is demonstrated in the article: calculation of telecommunication disturbances caused by a railway line with booster transformers in an armored cable. 10 refs, 10 figs, 2 tabs

Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

Science.gov (United States)

Chen, Chao; Li, Xiaodong; Thiele, Frank

2018-06-01

For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

Incorporation of phosphorus guest ions in the calcium silicate phases of Portland cement from 31P MAS NMR spectroscopy.

Science.gov (United States)

Poulsen, Søren L; Jakobsen, Hans J; Skibsted, Jørgen

2010-06-21

Portland cements may contain small quantities of phosphorus (typically below 0.5 wt % P(2)O(5)), originating from either the raw materials or alternative sources of fuel used to heat the cement kilns. This work reports the first (31)P MAS NMR study of anhydrous and hydrated Portland cements that focuses on the phase and site preferences of the (PO(4))(3-) guest ions in the main clinker phases and hydration products. The observed (31)P chemical shifts (10 to -2 ppm), the (31)P chemical shift anisotropy, and the resemblance of the lineshapes in the (31)P and (29)Si MAS NMR spectra strongly suggest that (PO(4))(3-) units are incorporated in the calcium silicate phases, alite (Ca(3)SiO(5)) and belite (Ca(2)SiO(4)), by substitution for (SiO(4))(4-) tetrahedra. This assignment is further supported by a determination of the spin-lattice relaxation times for (31)P in alite and belite, which exhibit the same ratio as observed for the corresponding (29)Si relaxation times. From simulations of the intensities, observed in inversion-recovery spectra for a white Portland cement, it is deduced that 1.3% and 2.1% of the Si sites in alite and belite, respectively, are replaced by phosphorus. Charge balance may potentially be achieved to some extent by a coupled substitution mechanism where Ca(2+) is replaced by Fe(3+) ions, which may account for the interaction of the (31)P spins with paramagnetic Fe(3+) ions as observed for the ordinary Portland cements. A minor fraction of phosphorus may also be present in the separate phase Ca(3)(PO(4))(2), as indicated by the observation of a narrow resonance at delta((31)P) = 3.0 ppm for two of the studied cements. (31)P{(1)H} CP/MAS NMR spectra following the hydration of a white Portland cement show that the resonances from the hydrous phosphate species fall in the same spectral range as observed for (PO(4))(3-) incorporated in alite. This similarity and the absence of a large (31)P chemical shift ansitropy indicate that the hydrous (PO(4

Power System Stability Using Decentralized Under Frequency and Voltage Load Shedding

DEFF Research Database (Denmark)

Hoseinzadeh, Bakhtyar; Silva, Filipe Faria Da; Bak, Claus Leth

2014-01-01

information to shed the loads with higher voltage decay first. Therefore, this approach deals with coordination of voltage and frequency information instead of independent methods. Numerical simulations which are carried out in DigSilent PowerFactory software confirm the efficiency of proposed methodology...

Gravitational dynamos and the low-frequency geomagnetic secular variation.

Science.gov (United States)

Olson, P

2007-12-18

Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions.

Spin polarization of {sup 87}Rb atoms with ultranarrow linewidth diode laser: Numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Wang, Z. G. [College of OptoElectronic Science and Engineering, National University of Defense Technology, Changsha, 410073 (China); Interdisciplinary Center of Quantum Information, National University of Defense Technology, Changsha, 410073 (China); College of Science, National University of Defense Technology, Changsha, 410073 (China); Jiang, Q. Y.; Zhan, X.; Chen, Y. D.; Luo, H., E-mail: luohui.luo@163.com [College of OptoElectronic Science and Engineering, National University of Defense Technology, Changsha, 410073 (China); Interdisciplinary Center of Quantum Information, National University of Defense Technology, Changsha, 410073 (China)

2016-08-15

In order to polarize {sup 87}Rb vapor effectively with ultranarrow linewidth diode laser, we studied the polarization as a function of some parameters including buffer gas pressure and laser power. Moreover, we also discussed the methods which split or modulate the diode laser frequency so as to pump the two ground hyperfine levels efficiently. We obtained some useful results through numerical simulation. If the buffer gas pressure is so high that the hyperfine structure is unresolved, the polarization is insensitive to laser frequency at peak absorption point so frequency splitting and frequency modulation methods do not show improvement. At low pressure and laser power large enough, where the hyperfine structure is clearly resolved, frequency splitting and frequency modulation methods can increase polarization effectively. For laser diodes, frequency modulation is easily realized with current modulation, so this method is attractive since it does not add any other components in the pumping laser system.

Can numerical simulations accurately predict hydrodynamic instabilities in liquid films?

Science.gov (United States)

Denner, Fabian; Charogiannis, Alexandros; Pradas, Marc; van Wachem, Berend G. M.; Markides, Christos N.; Kalliadasis, Serafim

2014-11-01

Understanding the dynamics of hydrodynamic instabilities in liquid film flows is an active field of research in fluid dynamics and non-linear science in general. Numerical simulations offer a powerful tool to study hydrodynamic instabilities in film flows and can provide deep insights into the underlying physical phenomena. However, the direct comparison of numerical results and experimental results is often hampered by several reasons. For instance, in numerical simulations the interface representation is problematic and the governing equations and boundary conditions may be oversimplified, whereas in experiments it is often difficult to extract accurate information on the fluid and its behavior, e.g. determine the fluid properties when the liquid contains particles for PIV measurements. In this contribution we present the latest results of our on-going, extensive study on hydrodynamic instabilities in liquid film flows, which includes direct numerical simulations, low-dimensional modelling as well as experiments. The major focus is on wave regimes, wave height and wave celerity as a function of Reynolds number and forcing frequency of a falling liquid film. Specific attention is paid to the differences in numerical and experimental results and the reasons for these differences. The authors are grateful to the EPSRC for their financial support (Grant EP/K008595/1).

Natural Frequency of F.G. Rectangular Plate by Shear Deformation Theory

International Nuclear Information System (INIS)

Shahrjerdi, Ali; Sapuan, S M; Shahzamanian, M M; Mustapha, F; Zahari, R; Bayat, M

2011-01-01

Natural frequency of functionally graded (F.G.) rectangular plate is carried out by using second-order shear deformation theory (SSDT). The material properties of functionally graded rectangular plates, except the Poisson's ratio, are assumed to vary continuously through the thickness of the plate in accordance with the exponential law distribution. The equations of motion are obtained by energy method. Numerical results for functionally graded plates are given in dimensionless graphical forms and the effects of material properties on natural frequency are determined.

Simulation of dust particles in dual-frequency capacitively coupled silane discharges

International Nuclear Information System (INIS)

Liu Xiangmei; Song Yuanhong; Xu Xiang; Wang Younian

2010-01-01

The behavior of nanoparticles in dual-frequency capacitively coupled silane discharges is investigated by employing a one-dimensional self-consistent fluid model. The numerical simulation tries to trace the formation, charging, growth, and transport of dust particles during the discharge, under the influences of the high- and low-frequency electric sources, as well as the gas pressure. The effects of the presence of the nanoparticles and larger anions on the plasma properties are also discussed, especially, for the bulk potential, electron temperature, and densities of various particles. The calculation results show that the nanoparticle density and charge distribution are mainly influenced by the voltage and frequency of the high-frequency source, while the voltage of the low-frequency source can also exert an effect on the nanoparticle formation, compared with the frequency. As the discharge lasts, the electric potential and electron density keep decreasing, while the electron temperature gets increasing after a sudden drop.

Laser frequency stabilization using bichromatic crossover spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Jeong, Taek; Seb Moon, Han, E-mail: hsmoon@pusan.ac.kr [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of)

2015-03-07

We propose a Doppler-free spectroscopic method named bichromatic crossover spectroscopy (BCS), which we then use for the frequency stabilization of an off-resonant frequency that does not correspond to an atomic transition. The observed BCS in the 5S{sub 1/2} → 5P{sub 1/2} transition of {sup 87}Rb is related to the hyperfine structure of the conventional saturated absorption spectrum of this transition. Furthermore, the Doppler-free BCS is numerically calculated by considering all of the degenerate magnetic sublevels of the 5S{sub 1/2} → 5P{sub 1/2} transition in an atomic vapor cell, and is found to be in good agreement with the experimental results. Finally, we successfully achieve modulation-free off-resonant locking at the center frequency between the two 5S{sub 1/2}(F = 1 and 2) → 5P{sub 1/2}(F′ = 1) transitions using a polarization rotation of the BCS. The laser frequency stability was estimated to be the Allan variance of 2.1 × 10{sup −10} at 1 s.

NUMERICAL WITHOUT ITERATION METHOD OF MODELING OF ELECTROMECHANICAL PROCESSES IN ASYNCHRONOUS ENGINES

Directory of Open Access Journals (Sweden)

D. G. Patalakh

2018-02-01

Full Text Available Purpose. Development of calculation of electromagnetic and electromechanic transients is in asynchronous engines without iterations. Methodology. Numeral methods of integration of usual differential equations, programming. Findings. As the system of equations, describing the dynamics of asynchronous engine, contents the products of rotor and stator currents and product of rotation frequency of rotor and currents, so this system is nonlinear one. The numeral solution of nonlinear differential equations supposes an iteration process on every step of integration. Time-continuing and badly converging iteration process may be the reason of calculation slowing. The improvement of numeral method by the way of an iteration process removing is offered. As result the modeling time is reduced. The improved numeral method is applied for integration of differential equations, describing the dynamics of asynchronous engine. Originality. The improvement of numeral method allowing to execute numeral integrations of differential equations containing product of functions is offered, that allows to avoid an iteration process on every step of integration and shorten modeling time. Practical value. On the basis of the offered methodology the universal program of modeling of electromechanics processes in asynchronous engines could be developed as taking advantage on fast-acting.

Controlling Energy Radiations of Electromagnetic Waves via Frequency Coding Metamaterials.

Science.gov (United States)

Wu, Haotian; Liu, Shuo; Wan, Xiang; Zhang, Lei; Wang, Dan; Li, Lianlin; Cui, Tie Jun

2017-09-01

Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits "0" and "1" to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency-spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.

Frequency-Wavenumber (FK)-Based Data Selection in High-Frequency Passive Surface Wave Survey

Science.gov (United States)

Cheng, Feng; Xia, Jianghai; Xu, Zongbo; Hu, Yue; Mi, Binbin

2018-04-01

Passive surface wave methods have gained much attention from geophysical and civil engineering communities because of the limited application of traditional seismic surveys in highly populated urban areas. Considering that they can provide high-frequency phase velocity information up to several tens of Hz, the active surface wave survey would be omitted and the amount of field work could be dramatically reduced. However, the measured dispersion energy image in the passive surface wave survey would usually be polluted by a type of "crossed" artifacts at high frequencies. It is common in the bidirectional noise distribution case with a linear receiver array deployed along roads or railways. We review several frequently used passive surface wave methods and derive the underlying physics for the existence of the "crossed" artifacts. We prove that the "crossed" artifacts would cross the true surface wave energy at fixed points in the f-v domain and propose a FK-based data selection technique to attenuate the artifacts in order to retrieve the high-frequency information. Numerical tests further demonstrate the existence of the "crossed" artifacts and indicate that the well-known wave field separation method, FK filter, does not work for the selection of directional noise data. Real-world applications manifest the feasibility of the proposed FK-based technique to improve passive surface wave methods by a priori data selection. Finally, we discuss the applicability of our approach.

Frequency-Wavenumber (FK)-Based Data Selection in High-Frequency Passive Surface Wave Survey

Science.gov (United States)

Cheng, Feng; Xia, Jianghai; Xu, Zongbo; Hu, Yue; Mi, Binbin

2018-07-01

Passive surface wave methods have gained much attention from geophysical and civil engineering communities because of the limited application of traditional seismic surveys in highly populated urban areas. Considering that they can provide high-frequency phase velocity information up to several tens of Hz, the active surface wave survey would be omitted and the amount of field work could be dramatically reduced. However, the measured dispersion energy image in the passive surface wave survey would usually be polluted by a type of "crossed" artifacts at high frequencies. It is common in the bidirectional noise distribution case with a linear receiver array deployed along roads or railways. We review several frequently used passive surface wave methods and derive the underlying physics for the existence of the "crossed" artifacts. We prove that the "crossed" artifacts would cross the true surface wave energy at fixed points in the f- v domain and propose a FK-based data selection technique to attenuate the artifacts in order to retrieve the high-frequency information. Numerical tests further demonstrate the existence of the "crossed" artifacts and indicate that the well-known wave field separation method, FK filter, does not work for the selection of directional noise data. Real-world applications manifest the feasibility of the proposed FK-based technique to improve passive surface wave methods by a priori data selection. Finally, we discuss the applicability of our approach.