Spin motive forces due to magnetic vortices and domain walls

We study spin motive forces, i.e, spin-dependent forces, and voltages induced by time-dependent magnetization textures, for moving magnetic vortices and domain walls. First, we consider the voltage generated by a one-dimensional field-driven domain wall. Next, we perform detailed calculations on field-driven vortex domain walls. We find that the results for the voltage as a function of magnetic field differ between the one-dimensional and vortex domain wall. For the experimentally relevant case of a vortex domain wall, the dependence of voltage on field around Walker breakdown depends qualitatively on the ratio of the so-called $\beta$-parameter to the Gilbert damping constant, and thus provides a way to determine this ratio experimentally. We also consider vortices on a magnetic disk in the presence of an AC magnetic field. In this case, the phase difference between field and voltage on the edge is determined by the $\beta$ parameter, providing another experimental method to determine this quantity.Comment: 8 pages, 9 figures, submitted to PR

Postidentification Feedback Influence Through Nonverbal Cues

For many years, psychologists and other social scientists have investigated the influence of postidentification verbal feedback on eyewitnesses’ identifications. However, the purpose of this study was to examine if the impact of nonverbal postidentification feedback cues on eyewitnesses’ confidence level can have the same effect as verbal postidentification feedback. The postidentification feedback effect has been well documented in regards to verbal feedback. The research questions for this study examined what effects on eyewitnesses’ confidence level that positive and negative nonverbal feedback would have. Participants (N=66) were selected at random from a local park and placed into one treatment group (positive, negative or no nonverbal feedback). Two separate questionnaires were completed by the participants and measured using a Likert scale. To conduct this quantitative study a mixed ANOVA was done to see the relationships between and within the pretreatment and posttreatment groups. The results indicate that there was a significant change in eyewitnesses’ confidence level after receiving the corresponding feedback. This indicates that an eyewitness can also be influenced by post identification feedback using nonverbal cues. Recommendations are made for ways of improving the lineup administration and other eyewitness identification processes to address common concerns associated with the current procedures and best practices. These findings can contribute to positive social change in law enforcement departments self-assessing their policy and procedures. This can also lead to less bias and suggestibility within the entire criminal justice system

Hidden order in bosonic gases confined in one dimensional optical lattices

We analyze the effective Hamiltonian arising from a suitable power series expansion of the overlap integrals of Wannier functions for confined bosonic atoms in a 1d optical lattice. For certain constraints between the coupling constants, we construct an explicit relation between such an effective bosonic Hamiltonian and the integrable spin-$S$ anisotropic Heisenberg model. Therefore the former results to be integrable by construction. The field theory is governed by an anisotropic non linear $\sigma$-model with singlet and triplet massive excitations; such a result holds also in the generic non-integrable cases. The criticality of the bosonic system is investigated. The schematic phase diagram is drawn. Our study is shedding light on the hidden symmetry of the Haldane type for one dimensional bosons.Comment: 5 pages; 1 eps figure. Revised version, to be published in New. J. Phy

Incomplete Dissociation in Solutions of Strong Electrolytes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70904/2/JCPSA6-9-3-283-1.pd

Field induced d_x^2-y^2+id_xy state in d-density-wave metals

We argue that the d_{xy} component of the order parameter can be generated to form the d_x^2-y^2+id_xy-density wave state by the external magnetic field. The driving force for this transition is the coupling of the magnetic field with the orbital magnetism. The fully gapped particle spectrum and the magnetically active collective mode of the condensate are discussed as a possible signature of the d+id' density wave state.Comment: 5 pages, 2 color figure

Geometry and the Hidden Order of Luttinger Liquids: the Universality of Squeezed Space

We present the case that Luttinger liquids are characterized by a form of hidden order which is similar, but distinct in some crucial regards, to the hidden order characterizing spin-1 Heisenberg chains. We construct a string correlator for the Luttinger liquid which is similar to the string correlator constructed by den Nijs and Rommelse for the spin chain. From a geometric prespective on the so-called `squeezed space' construction, we demonstrate that the physics at long wavelength can be reformulated in terms of a $Z_2$ gauge theory. Peculiarly, the normal spin chain lives at infinite gauge coupling where it is characterized by deconfinement. We identify the microscopic conditions required for confinement thereby identifying a novel phase of the spin-chain. We demonstrate that the Luttinger liquid can be approached in the same general framework. The difference from the spin chain is that the gauge sector is critical in the sense that the Luttinger liquid is at the phase boundary where the $Z_2$ local symmetry emerges. We evaluate the string correlator analytically and show that the squeezed space structure is present both for the strongly coupled Hubbard model and the non-interacting fermion gas. These structures are hard-wired in the mathematical structure of bosonization and this becomes obvious by considering string correlators. Numerical results are presented for the string correlator using a non-abelian version of the density matrix renormalization group algorithm, confirming in detail the expectations following from the theory. We conclude with some observations regarding the generalization of bosonization to higher dimensions.Comment: 24 pages, 14 eps figures, Revtex

Coercive, enabling, diagnostic, and interactive control: Unravelling the puzzle of their connections

Recent accounting research has connected the typology of coercive and enabling types of formalisation (Adler and Borys, 1996) (A&B96) with the distinction between diagnostic and interactive control as proposed by Simons (1995, 2000) (LOC) in order to tackle research questions on complex control situations that involve both the degree of employees’ autonomy and the patterns of top management attention. In this paper, we assess the extent to which the conceptual clarity of the connection between A&B96 and LOC is at risk. Based on an in-depth content analysis of 59 recent papers drawing on A&B96 and/or LOC, we observe some key points of ambiguity and divergence across frameworks (the perspective from which reality is being studied and the decision focus; whether categories capture choices driven by design or by style-of-use; the properties of control systems). We observe an additional source of divergence resulting from the different forms of connection that are proposed (co-existence, inclusion and combination approaches). We assess how the identified points of ambiguity and divergence across frameworks manifest in each approach. Based on this assessment, we provide guidelines to enhance conceptual clarity in future accounting research interested in drawing upon both A&B96 and LOC frameworks. We further propose a series of generic research models under different forms of connection between the two frameworks, pointing out some opportunities for future conceptually clear research

Estudios preliminares para la determinación de la resistencia a cortadura interlaminar ST mediante los ensayos Iosipescu y "Short beam shear"

La resistencia a cortadura interlaminar ST es una característica del material que juega un papel significativo en algunos de los criterios de fallo de la matriz en compresión con más repercusión en la actualidad (e.g.: Hashin, Puck, "World Wide Failure Exercise", 1998, 2002). Sin embargo, dicha característica resulta difícil de medir experimentalmente, por lo que es común la aproximación de dicho valor a partir de otras características del material que resultan más simples de determinar (resistencia a cortadura intralaminar S, resistencia a compresión perpendicular a las fibras YC, resistencia a cortadura en el ensayo "Short Beam Shear", SBS). En este trabajo se realiza un estudio acerca de la posibilidad de medir la resistencia a cortadura interlaminar ST empleando una configuración modificada de la probeta Iosipescu, y mediante una variante del ensayo SBS con las fibras perpendiculares a la dirección longitudinal de la probeta. Los resultados obtenidos para las diferentes configuraciones, y para distintas dimensiones de las probetas son analizados en el presente estudio.Ministerio de Ciencia y Tecnología MAT2000-111

Aerosol Route to Antibacterial Nanosilver Coating of Cotton Fabrics

The paper describes a gas phase process for the preparation of cotton fabrics coated with silver nanoparticles as antimicrobial agents. Silver nanoparticles are synthesized by means of atmospheric pressure electrical discharges (spark discharge and glow discharge) in pure inert gases, and the aerosols are passed through cotton fabric samples, where nanoparticles deposit. The particle size distribution of the aerosols is measured online during synthesis. Also, the cristallinity, size and morphology of the silver particles are analyzed. The mean size of the primary particles of silver varies from 4 nm to 18 nm, depending upon the type of discharge, the nature and flow rate of the gas. The bactericidal activity of the cotton samples doped with silver nanoparticles is assessed following the ISO 20743 method. All cotton samples show significant bactericidal property, although it degrades with increasing primary particle size and particle agglomeration. This purely physical aerosol route is a promising sustainable method for nanocoating of textiles