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Microclimate of Atlantic forest fragments: regional and local scale heterogeneity
Ramos, Flavio Nunes;Santos, Flavio Antonio Ma?s;
Brazilian Archives of Biology and Technology , 2006, DOI: 10.1590/S1516-89132006000700011
Abstract: the aim of this work was to investigate whether (i) the organisms within different fragments, on regional scale (separated by up to 100 km), could be submitted to similar climatic conditions (rainfall and temperature), and whether (ii) the edge formation in forest fragments could stimulate microclimatic changes (canopy cover, air temperature and soil humidity), on local scale. the organisms within different fragments, on regional scale, were submitted to different climatic conditions, and the edge formation in the forest fragment stimulated microclimatic changes, on local scale, although in a heterogenic way. not just the distance from the edge influenced the microclimatic differences. probably, the edge age, location, the matrix structure, as well as, gap proximity could change the microclimatic even within edges.
Spectroscopic studies of fractal aggregates of silver nanospheres undergoing local restructuring  [PDF]
Sergei V. Karpov,Valeriy S. Gerasimov,Ivan L. Isaev,Vadim A. Markel
Physics , 2006, DOI: 10.1063/1.2229202
Abstract: We present an experimental spectroscopic study of large random colloidal aggregates of silver nanoparticles undergoing local restructuring. We argue that such well-known phenomena as strong fluctuation of local electromagnetic fields, appearance of "hot spots" and enhancement of nonlinear optical responses depend on the local structure on the scales of several nanosphere diameters, rather that the large-scale fractal geometry of the sample.
Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles  [PDF]
Sergei V. Karpov,Valeriy S. Gerasimov,Ivan L. Isaev,Vadim A. Markel
Physics , 2005, DOI: 10.1103/PhysRevB.72.205425
Abstract: We have shown within the quasistatic approximation that the giant fluctuations of local electromagnetic field in random fractal aggregates of silver nanospheres are strongly correlated with a local anisotropy factor S which is defined in this paper. The latter is a purely geometrical parameter which characterizes the deviation of local environment of a given nanosphere in an aggregate from spherical symmetry. Therefore, it is possible to predict the sites with anomalously large local fields in an aggregate without explicitly solving the electromagnetic problem. We have also demonstrated that the average (over nanospheres) value of S does not depend noticeably on the fractal dimension D, except when D approaches the trivial limit D=3. In this case, as one can expect, the average local environment becomes spherically symmetrical and S approaches zero. This corresponds to the well-known fact that in trivial aggregates fluctuations of local electromagnetic fields are much weaker than in fractal aggregates. Thus, we find that, within the quasistatics, the large-scale geometry does not have a significant impact on local electromagnetic responses in nanoaggregates in a wide range of fractal dimensions. However, this prediction is expected to be not correct in aggregates which are sufficiently large for the intermediate- and radiation-zone interaction of individual nanospheres to become important.
Sequential tasks performed by catalytic pumps for colloidal crystallization  [PDF]
Ali Afshar Farniya,Maria J. Esplandiu,Adrian Bachtold
Physics , 2014,
Abstract: Gold-platinum catalytic pumps immersed in a chemical fuel are used to manipulate silica colloids. The manipulation relies on the electric field and the fluid flow generated by the pump. Catalytic pumps perform various tasks, such as the repulsion of colloids, the attraction of colloids, and the guided crystallization of colloids. We demonstrate that catalytic pumps can execute these tasks sequentially over time. Switching from one task to the next is related to the local change of the proton concentration, which modifies the colloid zeta potential and consequently the electric force acting on the colloids.
Microclimate depending on solar radiation
Ji?í Labudek,Lenka Michnová,Lubomír Martiník,Marcela ?erníková
GRANT journal , 2012,
Abstract: In the project “SP2011/182-Gradient temperature and airflow changes in the transparent shell caused by solar radiation” a long-time measurements in space of emergency staircase near transparent facade shell were taken. The effect of global solar radiation on the microclimate and the thermal stability of the internal environment were monitored. The paper is based on the values obtained from the current measurements in the period May - August 2011.
Effects of Recycled Tires Rubber Aggregates on the Characteristics of Cement Concrete  [PDF]
Zeineddine Boudaoud, Miloud Beddar
Open Journal of Civil Engineering (OJCE) , 2012, DOI: 10.4236/ojce.2012.24025
Abstract: This experimental work investigates the impact of substituting part of the conventional aggregates with rubber aggregates on certain characteristics of the cement concretes. This incorporation of rubber aggregates resulting from cutting worn tires in practical sizes decreases the mechanical resistances of the concretes while improving slightly the fluidity of the tested mixtures. The effect of these aggregates on the shrinkage of the concretes at an early age is appreciable and even very interesting for the concretes used, for example, in road construction. This technique of cutting worn tires without any further treatment makes it accessible to everyone which helps not only in saving the environment by getting rid of this cumbersome waste but also in saving traditional aggregates.
Transport and Dissipation in Quantum Pumps  [PDF]
J. E. Avron,A. Elgart,G. M. Graf,L. Sadun
Physics , 2003, DOI: 10.1023/B:JOSS.0000037245.45780.e1
Abstract: This paper is about adiabatic transport in quantum pumps. The notion of ``energy shift'', a self-adjoint operator dual to the Wigner time delay, plays a role in our approach: It determines the current, the dissipation, the noise and the entropy currents in quantum pumps. We discuss the geometric and topological content of adiabatic transport and show that the mechanism of Thouless and Niu for quantized transport via Chern numbers cannot be realized in quantum pumps where Chern numbers necessarily vanish.
Versatile Implementation in Angle-Resolved Optical Microscopy: Its Application to Local Spectrometry of Microcavities with PIC-J-Aggregates  [PDF]
Yuki Obara,Keita Saitoh,Masaru Oda,Toshiro Tani
International Journal of Spectroscopy , 2011, DOI: 10.1155/2011/523017
Abstract: Versatile novel implementations in microspectroscopy are developed, which can provide angle-resolved optical spectroscopy at local sample areas almost in diffraction limit. By selecting focus position of light flux incident within the back focal plane of the objective lens radially from the position of the optical axis of the microscope with employing off-centered pinhole, we can obtain parallel beam with oblique incidence and its angle tuning at the sample surface. In this paper, we describe our specific optical setup and its practical working principle in detail. We report, as a demonstration of its performance, our latest studies on optical properties of cavity polariton states in the so-called quantum microcavity structures, which contain molecular J-aggregates of pseudoisocyanine (PIC) dye as active working materials. By using the microscope technique, we obtain a fair amount of improvement in the linewidth observation of cavity polariton spectra. 1. Introduction With spectacular development of recent microfabrication technologies, it is increasingly important to monitor optical properties of matters at its more minute levels. As a result, the studies with microspectroscopy, the combination of traditional optical microscope and spectroscopic measurement, have been widely conducted. One of the most significant and informative spectroscopic techniques is the observation of the angle-resolved optical features. Nevertheless, implementations for such microspectroscopes have never been reported within our knowledge. Here we have developed novel optical microscopy system which can provide observations on the angular-dependent optical features at local sample regions almost to its diffraction-limited spatial resolution. This system should possess broader utilities and work in a wide variety of situations, for example, fundamental studies such as local optical spectra of materials with specifically fabricated structures, evaluations of microfabricated photonic as well as electronic functional devices. In this paper, specific optical microscope system with incident-angle-tunable Koehler type illumination is reported and its practical working principle as well. In addition, we introduce part of our latest studies about reflectance spectrometric measurement of molecular J-aggregates consist of pseudoisocyanine (PIC; 1,1′-diethyl-2,2′-cyanine chloride) dye in metal-mirror microcavity structures, as an example of the application of such system. The microcavities containing J-aggregates are known as the useful structures to form strong-coupling states between
Optimal Quantum Pumps  [PDF]
J. E. Avron,A. Elgart,G. M. Graf,L. Sadun
Physics , 2001, DOI: 10.1103/PhysRevLett.87.236601
Abstract: We study adiabatic quantum pumps on time scales that are short relative to the cycle of the pump. In this regime the pump is characterized by the matrix of energy shift which we introduce as the dual to Wigner's time delay. The energy shift determines the charge transport, the dissipation, the noise and the entropy production. We prove a general lower bound on dissipation in a quantum channel and define optimal pumps as those that saturate the bound. We give a geometric characterization of optimal pumps and show that they are noiseless and transport integral charge in a cycle. Finally we discuss an example of an optimal pump related to the Hall effect.
Who's saving the files? Towards a new role for local map collections?  [cached]
Robert B. Parry
Liber Quarterly : The Journal of European Research Libraries , 2003,
Abstract: Today's geography is tomorrow's history. As spatial data become digital, we are in danger of losing that history. The high profile of government mapping agencies has ensured the preservation of present and future time slices of our evolving topography, but there are many other data sets to consider: thematic, often ephemeral, and sometimes of only local significance. Digital data are more easily lost than paper-based records. Should it be the responsibility of the data providers to archive their data, or do national and local map collections have a role to play in acquiring, archiving, and making such data available? The paper considers these issues, taking examples from the UK and from the author's local region.
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