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Kinetics and Thermodynamics of Interaction between Amphiphiles and Membranes: Interplay of Amphiphile Dipole Moment and Membrane Dipole Potential

Cardoso, Renato Manuel Soares
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
36.48%
The passive permeation across biological membranes is a main route determining a drug bioavailability. However, the prediction of its permeability requires the quantitative knowledge of the kinetic parameters for interaction with the distinct membrane barriers (insertion, desorption and translocation). For most drugs this kinetic profile is unknown and their permeability rate is estimated based on their general hydrophobicity, accessed through partition between octanol and water. Considering that membranes are highly anisotropic systems, the comparison with homogenous phases is simpleminded. The orientation of the lipids in membranes, with their polar groups oriented to the aqueous phase and the non-polar hydrocarbon chains oriented towards the bilayer mid-plane, generates transversal gradients of polarity, density and charge. One important property that arises from this asymmetry is the dipole potential. Moreover, most drugs and biological ligands have an asymmetrical charge distribution, and the interplay between the amphiphile dipole moment and membrane potential is expected to play a important role in their interaction parameters. This question has however been overlooked by the scientific community. In this work we presented a detailed study of the kinetics and thermodynamics of the interaction between two fluorescent amphiphilic molecules...

Estudo experimental de uma ligação viga-pilar de concreto pré-moldado parcialmente resistente a momento fletor; Experimental study of a partial moment resistant beam-to-column connection in precast concrete

Baldissera, Alice
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/05/2006 PT
Relevância na Pesquisa
36.33%
Neste trabalho estudou-se o comportamento de uma ligação viga-pilar de estrutura pré-moldada parcialmente resistente a momento fletor quando submetida a momentos negativos e positivos. A ligação estudada é composta por dois chumbadores inclinados presos à viga através de chapa metálica, porcas e arruelas e uma capa de concreto com armadura longitudinal passando por dentro do pilar. No programa experimental foram elaborados dois modelos submetidos a carregamentos alternados, em ciclos e de curta duração. Em seguida foi desenvolvido um modelo analítico para cálculo dos momentos resistentes e feita uma simulação numérica para avaliar a influência da semi-rigidez da ligação em estruturas típicas de concreto pré-moldado. Os resultados experimentais indicaram que a ligação apresenta uma boa capacidade de transmissão a momento fletor negativo e a momento fletor positivo com um comportamento bastante dúctil. Sem a necessidade de grandes alterações de custos e de execução, a ligação proposta promoveu uma redução significativa dos momentos na base dos pilares (aproximadamente 50%) quando comparada à ligação articulada. Quando comparada à ligação similar, porém com os chumbadores retilíneos, há um aumento superior a 2...

Modelo para estimativa de força e torque dos músculos rotadores externos do ombro no plano transverso; Model for force and moment prediction of shoulder external rotation muscles in the transverse plane

Castro, Marcelo Peduzzi de; Marques, Felipe Osorio; Toledo, Joelly Manhic de; Costa, Juliana Motta; Krug, Roberto Costa; Ribeiro, Daniel Cury; Loss, Jefferson Fagundes
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
36.4%
Estimar a forca dos musculos do ombro e compreender o quanto cada musculo contribui para producao do torque em determinado movimento articular torna-se indispensavel para a compreensao do movimento humano, bem como para o planejamento da reabilitacao de pacientes com disfuncoes no ombro. Neste sentido, o presente estudo tem como principal objetivo estimar a forca muscular e analisar a contribuicao dos musculos Infra-espinhoso, Redondo Menor, Supra-espinhoso, Deltoide Posterior e Deltoide Medio no torque de rotacao externa dinamico do ombro no plano transverso. Para isso, um modelo de otimizacao gerado no software MATLAB. 7.0 (MathWork Inc, Massachusetts . USA), capaz de estimar a producao de forca e torque de cada um dos musculos rotadores externos do ombro foi utilizado.Os musculos Infra-espinhoso e Redondo Menor apresentaram um pico de torque de 22Nm em 20o e 6Nm em 28o, respectivamente, quando o ombro encontrava- se em rotacao interna. A magnitude maxima de forca alcancada por estes musculos foi de 996N para o Infraespinhoso e 306N para o Redondo Menor. Os musculos Supra-espinhoso, Deltoide Posterior e Deltoide Medio praticamente nao produziram torque e obtiveram magnitudes pequenas de forca. Estes resultados apontam que os musculos Infraespinhoso e Redondo Menor sao preferencialmente recrutados para o gesto de rotacao externa do ombro.; Estimating shoulder muscle forces and understanding the contribution of each muscle to the torque generated during joint movement is indispensable for the knowledge of the human movement...

The rates in complete moment convergence for negatively associated sequences

Zhao,Yuexu; Qiu,Zheyong; Zhang,Chunguo; Zhao,Yehua
Fonte: Sociedade Brasileira de Matemática Aplicada e Computacional Publicador: Sociedade Brasileira de Matemática Aplicada e Computacional
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
36.33%
Let X1, X2,... be a strictly stationary and negatively associated sequence of random variables with mean zero and positive, finite variance, set Sn = X1+ ... + Xn, Mn = max1 < k < n |Sk|. Under appropriate moment conditions, we obtain precise rates in law of the logarithm for the moment convergence of Sn and Mn.

Moment redistribution in continuous plated RC flexural members. Part 1: neutral axis depth approach and tests

Oehlers, D.; Ju, G.; Liu, I.; Seracino, R.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
36.45%
It is now common practice to retrofit or rehabilitate existing reinforced concrete beams and slabs by adhesively bonding fibre reinforced polymer (FRP) or metal plates to their surfaces. Advanced design rules are available for quantifying the various plate debonding mechanisms and consequently the shear and flexural capacities of the plated sections. These design rules show that even though the required increase in strength can be obtained by plating, plate debonding can severely reduce the ductility of a flexural member to such an extent that plating guidelines often exclude moment redistribution. This exclusion may reduce the application of plating, in particular to retrofitting buildings where ductility is often a requirement, or it may require the development of a radically different approach to design that does not rely implicitly on ductility. In this paper, it is shown that the commonly used neutral axis depth approach for moment redistribution in RC flexural members cannot be used for most plated structures because plate debonding often occurs before the concrete crushes. Tests on plated flexural members are also reported which show that moment redistribution can occur. In Part 2 of this paper, a moment redistribution analysis procedure is developed that can cope with plate debonding of externally bonded plates.; http://www.elsevier.com/wps/find/journaldescription.cws_home/30415/description#description; D. J. Oehlers...

Moment redistribution in continuous plated RC flexural members. Part 2: Flexural rigidity approach

Oehlers, D.; Liu, I.; Ju, G.; Seracino, R.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
36.4%
Adhesive bonding plates to the surfaces of reinforced concrete members is now frequently used to increase both the strength and stiffness. However, because of the brittle nature of the plate debonding mechanisms, plating is often assumed to reduce the ductility to such an extent that guidelines often preclude moment redistribution. Tests on seven full-scale flexural members have shown that significant amounts of moment can be redistributed from steel and carbon fibre reinforced polymer (FRP) plated regions. In this paper, a procedure is developed for quantifying the amount of moment redistribution that can occur in externally bonded steel or FRP plated members which can be used to design plated members for ductility.; http://www.elsevier.com/wps/find/journaldescription.cws_home/30415/description#description; D. J. Oehlers, I. S. T. Liu, G. Ju and R. Seracino

Moment inequalities for spatial processes

Gao, J.; Lu, Z.; Tjostheim, D.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
36.4%
This paper establishes a general moment inequality for spatial processes satisfying the α-mixing condition [cf., Tran, 1990. Kernel density estimation on random fields. J. Multivariate Analy. 34, 37–53]. Such a general moment inequality is a nontrivial extension of the corresponding result established in Cox and Kim [1995. Moment bounds for mixing random variables useful in nonparametric function estimation. Stochastic Process. Appl. 56, 151–158] for the time series case. As is the case for the Cox–Kim inequality for nonparametric estimation of time series, the new inequality is useful in nonparametric kernel estimation of spatial processes.; Jiti Gao, Zudi Lu and Dag Tjøstheim

Design for moment redistribution in RC beams retrofitted with steel plates

Haskett, M.; Oehlers, D.; Mohamed Sadakkathulla, M.
Fonte: Multi-science Publishing Publicador: Multi-science Publishing
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
36.48%
It is now common practice to retrofit reinforced concrete members by adhesively bonding steel or fibre reinforced polymer plates to their surfaces. However, tests have shown that these plated RC structures tend to have less member ductility, or rotational capacity, than the unplated structure because of premature plate debonding. In this paper, structural mechanics approaches are described for both: quantifying the moment rotation capacity, or member ductility, of steel plated RC flexural members; and quantifying the moment redistribution capacity from the moment rotation capacity. It is shown how the moment redistribution structural mechanics model can be used to design for member ductility directly and, furthermore, it is applied to both externally bonded and near surface mounted steel plates. As would be expected, it is shown that steel plating produces more ductile members than fibre reinforced polymer plating.; Matthew Haskett, Deric John Oehlers and M. S. Mohamed Ali

Analysis of moment redistribution in fiber-reinforced polymer plated RC beams

Haskett, M.; Oehlers, D.; Mat Ali, M.; Wu, C.
Fonte: American Society of Civil Engineers Publicador: American Society of Civil Engineers
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
36.58%
Ductility of RC structures has always been a classical area of concrete research. Given the complexity of the problem, the great mass of research investigating ductility, and specifically, moment redistribution and rotational capacities, has used empirical approaches to quantify moment redistribution and invariably assumed that concrete crushing is the singular mode of failure. With the advent of new reinforcement materials such as fiber reinforced polymers, these empirical approaches are not necessarily appropriate as failure modes other than concrete crushing can occur. In this paper, the empirical approaches to moment redistribution are replaced by a structural mechanics approach that incorporates moment rotation directly into moment redistribution. A structural mechanics method for determining moment and rotation at failure for any RC section with any material properties is first presented and this is followed by a structural mechanics model for moment redistribution; these enable the moment redistribution capacities of any RC section to be quantified. Moment redistribution capacities of various sections are analyzed and it is shown that plated sections can have significant moment redistribution capacities much of which can be used in design.; Matthew Haskett...

Method of Taylor expansion moment incorporating fractal theories for Brownian coagulation of fine particles

Wan, Z.; You, Z.; Sun, Z.; Yin, W.
Fonte: Walter de Gruyter GmbH & Co KG Publicador: Walter de Gruyter GmbH & Co KG
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.45%
Fine particles aggregating into larger units or flocculation body is a random combination process. Increasing the size and density of flocculation body is the main approach to rapid particle removal or sedimentation in water. Aiming at the Brownian coagulation of fine particles, a new method of Taylor expansion moment construction of fractal flocs has been developed in this paper, incorporating the Taylor expansion approach based on the moment method and the fractal dimension of the floc structure originated from fractal theories. This method successfully overcomes the limit of previous moment methods that require pre-assumed particle size distribution. Results of the zero and second order moments of Brownian flocs from the proposed method are compared with those from the Laguerre method, integral moment method and finite element method. It is found that the higher accuracy and efficiency of computation have been achieved by the new method, compared to the previous ones. Effects of the fractal dimension on the zero and second order moments, geometric average volume and standard deviation are also analyzed using this method. The self-conservation characteristics of particle distribution is observed without presumption of initial distributions.; Zhanhong Wan...

Design for moment redistribution in FRP plated RC beams

Oehlers, D.; Haskett, M.; Mohamed Sadakkathulla, M.
Fonte: Techno-Press Publicador: Techno-Press
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
36.51%
Assessing the ductility of reinforced concrete sections and members has been a complex and intractable problem for many years. Given the complexity in estimating ductility, members are often designed specifically for strength whilst ductility is provided implicitly through the use of ductile steel reinforcing bars and by ensuring that concrete crushing provides the ultimate limit state. As such, the empirical hinge length and neutral axis depth approaches have been sufficient to estimate ductility and moment redistribution within the bounds of the test regimes from which they were derived. However, being empirical, these methods do not have a sound structural mechanics background and consequently have severe limitations when brittle materials are used and when concrete crushing may not occur. Structural mechanics based approaches to estimating rotational capacities and rotation requirements for given amounts of moment redistribution have shown that FRP plated reinforced concrete (RC) sections can have significant moment redistribution capacities. In this paper, the concept of moment redistribution in beams is explained and it is shown specifically how an existing RC member can be retrofitted with FRP plates for both strength and ductility requirements. Furthermore...

Moment Matching and Modal Truncation for Linear Systems

Hergenroeder, AJ
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
36.45%
While moment matching can effectively reduce the dimension of a linear, time-invariant system, it can simultaneously fail to improve the stable time-step for the forward Euler scheme. In the context of a semi-discrete heat equation with spatially smooth forcing, the high frequency modes are virtually insignificant. Eliminating such modes dramatically improves the stable time-step without sacrificing output accuracy. This is accomplished by modal filtration, whose computational cost is relatively palatable when applied following an initial reduction stage by moment matching. A bound on the norm of the difference between the transfer functions of the moment-matched system and its modally-filtered counterpart yields an intelligent choice for the mode of truncation. The dual-stage algorithm disappoints in the context of highly nonnormal semi-discrete convection-diffusion equations. There, moment matching can be ineffective in dimension reduction, precluding a cost-effective modal filtering step.

The Sobolev-type moment problem

Marcellán, Francisco; Szafraniec, Franciszek H.
Fonte: American Mathematical Society Publicador: American Mathematical Society
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em /08/2000 ENG
Relevância na Pesquisa
36.48%
We propose necessary and sufficient conditions for a bisequence of complex numbers to be a moment one of Sobolev type over the real line, the unit circle and the complex plane. We achieve this through converting the moment problem in question into a matrix one and utilizing some techniques coming from operator theory. This allows us to consider the Sobolev type moment problem in its full generality, not necessarily in the diagonal case and even of infinite order.; This research carried out within the framework of scientific and technical cooperation between Spain and Poland was supported by the Ministry of Foreign Affairs of Spain and the Committee of Scientific Research (KBN) of Poland, grand 07/R98. The work of Francisco Marcellán was also partially supported by Dirección General de Enseñanza Superior (DGES) of Spain, grant PB96-0120C03-01 and INTAS project INTAS-93-219Ext.; 9 pages, no figures.-- MSC2000 codes: Primary 44A99; Secondary 47B15, 47B20, 47B25.; MR#: MR1694873 (2000k:44006); Zbl#: Zbl 0951.44002

The moment problem for a Sobolev inner product

Barrios, Dolores; López Lagomasino, Guillermo; Pijeira, Héctor
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em /10/1999 ENG
Relevância na Pesquisa
36.4%
The concepts of definite and determinate Sobolev moment problem are introduced. The study of these questions is reduced to the definiteness or determinacy, respectively, of a system of classical moment problems by means of a canonical decomposition of the moment matrix associated with a Sobolev inner product in terms of Hankel matrices.; Research by second author (G.L.L.) was partially supported by Dirección General de Enseñanza Superior under Grant PB 96-0120-C03-01 and by INTAS under Grant 93-0219 EXT. Research by the third author (H.P.) was carried out while following a Doctoral Program at Universidad Carlos III de Madrid under a grant from Agencia Española de Cooperación Internacional.; 17 pages, no figures.-- MSC2000 code: 44A60.; MR#: MR1715024 (2000m:44013); Zbl#: Zbl 0980.44008

A moment plotting method for characterizing aircraft fatigue data population distributions

Lokensgard, Rolf M.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: 99 p.
EN_US
Relevância na Pesquisa
36.4%
Approved for public release; distribution is unlimited; A method was developed where, by statistically analyzing samples of aircraft fatigue data from a population, the population's probability distribution function is determined. The method uses plots of a sample's coefficient of variation, and measures of skewness and kurtosis, superimposed on templates of curves created from the moment functions of Normal, Lognormal, Weibull and Exponential distributions. The moment functions are derived for each distribution. The plotting technique is combined with a comparison of goodness of fit statistics to form the complete distribution selection method. The method is first tested on random numbers generated from known distributions to see if the correct distributions are selected; then the method is applied to helicopter loads data, fatigue life characterization test data, and counting accelerometer data; http://archive.org/details/momentplottingme00loke; Captain, United States Marine Corps

An Automated Approach for the Determination of the Seismic Moment Tensor in Mining Environments

Wamboldt, LAWRENCE
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.45%
A study was undertaken to evaluate an automated process to invert for seismic moment tensors from seismic data recorded in mining environments. The data for this study was recorded at Nickel Rim South mine, Sudbury, Ontario. The mine has a seismic monitoring system manufactured by ESG Solutions that performs continuous monitoring of seismicity. On average, approximately 400 seismic events are recorded each day. Currently, data are automatically processed by ESG Solution's software suite during acquisition. The automatic processors pick the P- and/or S-wave arrivals, locate the events and solve for certain source parameters, excluding the seismic moment tensor. In order to solve for the moment tensor, data must be manually processed, which is laborious and therefore seldom performed. This research evaluates an automatic seismic moment tensor inversion method and demonstrates some of the difficulties (through inversions of real and synthetic seismic data) of the inversion process. Results using the method are also compared to the inversion method currently available from ESG Solutions, which requires the manual picking of first-motion polarities for every event. As a result of the extensive synthetic testing of the automatic inversion program...

Les actions de groupes en géométrie symplectique et l'application moment

Payette, Jordan
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
Relevância na Pesquisa
36.4%
Ce mémoire porte sur quelques notions appropriées d'actions de groupe sur les variétés symplectiques, à savoir en ordre décroissant de généralité : les actions symplectiques, les actions faiblement hamiltoniennes et les actions hamiltoniennes. Une connaissance des actions de groupes et de la géométrie symplectique étant prérequise, deux chapitres sont consacrés à des présentations élémentaires de ces sujets. Le cas des actions hamiltoniennes est étudié en détail au quatrième chapitre : l'importante application moment y est définie et plusieurs résultats concernant les orbites de la représentation coadjointe, tels que les théorèmes de Kirillov et de Kostant-Souriau, y sont démontrés. Le dernier chapitre se concentre sur les actions hamiltoniennes des tores, l'objectif étant de démontrer le théorème de convexité d'Atiyha-Guillemin-Sternberg. Une discussion d'un théorème de classification de Delzant-Laudenbach est aussi donnée. La présentation se voulant une introduction assez exhaustive à la théorie des actions hamiltoniennes, presque tous les résultats énoncés sont accompagnés de preuves complètes. Divers exemples sont étudiés afin d'aider à bien comprendre les aspects plus subtils qui sont considérés. Plusieurs sujets connexes sont abordés...

Interpretação das intensidades do espectro de infravermelho das moleculas 'AB IND. 3'(A=N, P; B=H, F) utilizando o modelo QTAIM/CCFDF; A charge-chargeflux-dipole flux decomposition in the dipole moment derivatives and infrared intensities of the 'AB IND. 3'(A=N, P; B=H, F) molecules

Paulo Henrique Cesar
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/06/2007 PT
Relevância na Pesquisa
36.45%
A Teoria Quântica de Átomos em Moléculas (QTAIM) é utilizada para decompor as derivadas do momento dipolar e as intensidades de infravermelho das moléculas AB3 (A=N, P; B=H, F) em contribuições de carga¿fluxo de carga-fluxo de dipolo (CCFDF). Os cálculos realizados no nível MP2/6-311++G(3d,3p) obteve valores das intensidades de infravermelho com as cargas e dipolos atômicos QTAIM que diferem em 13,8 km mol dos valores experimentais não considerando as vibrações de estiramento das moléculas de NH3 e PH3, em que ocorrem sobreposição das bandas experimentais. Os dipolos atômicos dos átomos de nitrogênio e fósforo são muito importantes na determinação do momento dipolar das moléculas de NF3, PH3 e PF3, enquanto que as cargas atômicas são quase totalmente responsáveis pelo momento dipolar da molécula de NH3. O fluxo de dipolo do átomo central é mais importante na determinação das intensidades das bandas de estiramento de todas as moléculas, enquanto contribui muito pouco para as intensidades das bandas de deformação. As contribuições dos fluxos de dipolos dos átomos terminais devem ser consideradas para descrever com maior precisão as intensidades de todas as moléculas. A expectativa que se tem com o modelo momento de ligação simples...

Redundancy of moment conditions

Breusch, Trevor; Qian, H; Schmidt, P; Wyhowski, D
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.45%
It is well known that adding moment conditions cannot decrease asymptotic efficiency. However, sometimes additional moment conditions are redundant, in the sense that they do not increase the asymptotic efficiency of estimation for some or all of the parameters of interest. This paper gives a general treatment of redundancy of moment conditions. It provides necessary and sufficient conditions for redundancy, in several equivalent forms. The paper also provides interesting results for the case that there are three (or more) sets of moment conditions.

Imaging the earthquake cycle with the Moment-Ratio Method: An exploration

Zhang,C.; Shi,Y.; Ma,L.; Huang,J.; Lomnitz,C.
Fonte: Instituto de Geofísica, UNAM Publicador: Instituto de Geofísica, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2009 EN
Relevância na Pesquisa
36.48%
The seismic moment cycle at plate boundaries may be imaged by the Moment-Ratio Method (MRM). In this exploratory technique the fluctuation of cumulative moment deficiency is used as an indicator of the cycle of degradation and recovery of free energy along an active tectonic region. A 20-year half-life is assumed for the healing process of earthquake ruptures along the Pacific plate boundary. Using the Pacheco-Sykes Catalog of large shallow earthquakes (M>7), we estimate the moment ratio for Japan and Mexico at 20-year intervals during the 20th century. Moment-ratio peaks for 1980 correlate with subsequent earthquakes of magnitude M>7 during the following 20-year period in Mexico and Japan.