143,837 research outputs found
Characteristics of overlap region in high-Reynolds number turbulent channel flow
No full textDirect numerical simulation of the fully developed turbulent channel flows have been carried out at the Reynolds number based on the friction velocity and the channel half width, 2000, 4000 and 8000. A hybrid 10th order accurate finite difference scheme in the stream and spanwise directions, and a second-order scheme in the wall-normal direction is adapted as the spatial discretization method. We observed the plateau profiles in the indicator function corresponded to the von Karman constant. Furthermore, second peak of streamwise pre-multiplied spectra were appeared in the same wall normal height, 300 < y+ < 600, in case of Re = 4000. Nevertheless, the effects of the lager than the channel half height scale on the streamwise turbulent intensity are fixed contributions without dependence on Reynolds number. These results suggested that the new streamwise vortexes are formed between buffer layer and outer layer with increasing of Reynolds number
Conformational flexibility of membrane proteins in electric fields I. Ultraviolet absorbance and light scattering of bacteriorhodopsin in purple membranes
No full textTsuji K, Neumann E. Conformational flexibility of membrane proteins in electric fields I. Ultraviolet absorbance and light scattering of bacteriorhodopsin in purple membranes. Biophysical Chemistry. 1983;17(2):153-163
Skin friction factor and mean velocity profile measured in high-reynolds-number turbulent pipe flow
No full textA friction factor in a fully developed pipe flow is measured very accurately over wide range Reynolds number from 103 to 107 at the high Reynolds number facility in AIST,NMIJ. Also a velocity profile is measured by using a LDV up to 106. From the comparison between a velocity profile and the friction factor, we found that a log-law profile is well observed and Kármán constant is estimated to be 0.385. Based on the measurements, we present a new functional form of the friction factor which is consistent with mean velocity profile
Triflyl-assisted reductive Pd-catalyzed Tsuji-Trost type reaction
No full textNew (triflyl)cyclobutenes have been prepared by palladium-catalyzed hydrodetriflylation reaction using water and deuterium oxide as convenient hydrogen and deuterium sources. In addition, an investigation of the possible mechanism for this Tsuji-Trost type reaction of bis(triflyl)cyclobutenes has been facilitated by labelling studies and density functional theory (DFT) calculations.This work was supported in part by AEI (MICIU) and FEDER
(Projects PGC2018-095025-B-I00 and CTQ2016-79826-R).
M. T. Q. thanks MICIU for a Juan de la Cierva contract. C. L. M. thanks MICIU and UCM for a postdoctoral contract. We thank the
Centro de Computacio´n Cientı´fica-UAM for computational time.We
are grateful to Prof. B. Alcaide for his continued support
Comunicación corporativa y redes digitales
No full textVivimos en una época en la cual la incertidumbre domina los escenarios, donde la única certeza está en el cambio constante, en la ruptura de los viejos paradigmas hacia otros nuevos. En este marco, se observa cómo Internet, y sus nuevas tendencias, se presenta como una herramienta estratégica para la comunicación de pequeñas y medianas empresas (PYMES), organizaciones, como el caso de la web corporativa del FISEC, y transferencias realizadas al campo educativo, a partir de la implementación de publicaciones digitales que permiten el establecimiento de redes.Fil: Borea, Roberto Fabián. Universidad Nacional de La Matanza; Argentina.Fil: Tsuji, Teresa. Universidad Nacional de Lomas de Zamora; Argentin
Mechanistic Investigations into the Palladium-Catalyzed Decarboxylative Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture
No full textPalladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted.
Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.</p
Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
No full textIn this paper, the characteristics and the effectiveness of a nonlinear passive vibration isolator based on apost-buckled beam is investigated experimentally. The intended application is specifically isolation in thevertical direction where the isolator is required to be sufficiently stiff statically to bear the weight of theisolated mass. The isolator consists of two beams joined to form an inverted L-shape and the weight of theisolated mass is taken to act at the vertex. If the weight of isolated mass is larger than the buckling load of theL-shaped beam then the beam buckles in one of two modes, one of which is unstable. In this paper, the staticrestoring force of the unstable mode is measured and an appropriately selected coil spring is added tocounteract the negative stiffness of the beam. The resulting system presents a dramatically lower stiffness tosmall excursions about its equilibrium position in its buckled state but maintains its static load bearingcapability. Free vibration measurements are presented which show some amplitude dependency of the naturalfrequency for large amplitude motion. Low amplitude harmonic base excitation measurements are alsoconducted from which transmissibility measurements are obtained and compared with corresponding resultsfrom a Finite Element model. The fundamental resonance is about 80% lower than that achievable by acomparable linear isolator. However the potential improvement in isolation performance has not been fullyrealised in the prototype design due to the presence of higher frequency internal resonances of the isolator,mitigation of which is the focus of ongoing work
n-selective Tsuji–Trost allylation promoted by a recyclable TSIL-palladium complex
No full textThe Tsuji–Trost reaction of allylic acetates with nucleophiles is optimized using a task-specific ionic liquid (TSIL)-palladium complex in a very efficient manner. Several nucleophiles and allylic systems are studied obtaining very high yields of the corresponding products with total n-selectivity. The reaction is surveyed employing inexpensive allylic alcohols and 3-acyloxindole derivatives affording the expected allylated molecules after a deacylative process. The robustness of the catalytic system is assessed. The recovery and recycling of the whole catalytic system with the ionic liquid is also analyzed and the results are compared with previously reported articles in the literature.We gratefully acknowledge financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (projects CTQ2016-81893REDT, and RED2018-102387-T) the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P, CTQ2016-80375-P, CTQ2017-82935-P and PID2019-107268GB-I00), the Generalitat Valenciana (IDIFEDER/2021/013) and the University of Alicante (VIGROB-050, VIGROB-068, UADIF17-42 and UAUSTI16-02). Dr. D. Lledó thanks the Spanish Ministerio de Educación for the fellowship FPU15/00097
Emotional response in babies' pupil contagion
No full textRaw data and analysis code presented in Tsuji et al. (2023) Emotional response in babies' pupil contagion.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
STUDY OF LONG WAVE RESONANCE IN THE COLOMBIAN PACIFIC AND OTHER NATURAL BAYS BY MEANS OF PARAMETRIC EQUATIONS
No full textLas oscilaciones resonantes son un fenómeno conocido y bien documentado en gran número de puertos y bahías en todo el mundo (Vidal et al., 2000). El interés de realizar el seguimiento de estas oscilaciones radica en que todos los puertos y bahías en los que se han observado, alcanzan una gran amplitud y frecuencia lo que a su vez deriva en cuantiosos daños al afectar las estructuras del puerto y los barcos allí anclados, como se ha documentado para el puerto de Ciutadella. En el presente trabajo se realiza un análisis para observar este importante fenómeno en diferentes bahías natu-rales en el mundo; se han seleccionado 18 bahías en 8 países (Colombia, Honduras, Estados Unidos, España, Italia, Francia, Ucrania y Rumania), para lo cual se realiza un análisis por Ecuaciones Paramétricas: Los perío-dos propios de las bahías se determinaron mediante una simplificación de la fórmula de “Merian”, 1828 y las plataformas mediante el cálculo propuesto por Yanomi y Tsuji, 1998.Se demuestra por medio de este análisis cuales bahías son resonantes, y se concluye que los fenómenos reso-nantes no son un evento esporádico además que existe una relación directa entre la amplificación resonante de las bahías y las plataformas continentales donde están ubicadas y que debe ser motivo de estudio profundo debido a los desastres que puede causar en obras estructurales importantes.Resonant oscillations are a known and well documented phenomenon in many ports and harbors around the world (Vidal et al., 2000). The interest of monitoring of these oscillations is that all ports and bays which have been observed, reaching a large amplitude and frequency which in turn leads to extensive damage by affecting the harbor structures and ships at anchor, as documented for the port of Ciutadella.We have selected 18 bays in 8 countries (Colombia, Honduras, United States, Spain, Italy, France, Ukraine and Romania), for analysis of this important phenomenon observed in different natural harbors in the world, by Pa-rametric Equations: the vibration periods of the bays were determined by simplifying the formula of “Merian”, 1828 and platforms proposed by calculating Yanomi and Tsuji, 1998.Resonance was demonstrated for some bays, and we conclude that resonant phenomena are not a sporadic event, because including also a direct relationship between the resonant amplification of the bays and continen-tal shelves where they are located and which should be subject of a depth study due to disasters that can cause about major structural works
- …
