Volt-ampere characteristics of cylindrical and spherical Langmuir probes for various potential models Scientific report

Volt-ampere characteristics of cylindrical and spherical Langmuir probes for various potential model

Introduction to the Plasma Issue

The study of the physics of ionized gases has had a long and complicated history. The word "plasma" was first coined by Langmuir and Tonks in 1929 to denote a gas in which an important fraction of the molecules are dissociated into ions and electrons, the gas as a whole remaining electrically neutral. The laboratory study of plasmas, of course, had been pursued long before that, many important discoveries in the realm of gas discharge phenomena having been made in the 1800's. These studies, continuing into the Twentieth Century as exemplified by the work of Langmuir, served as the foundation for many practical electronic devices used for the generation, rectification, and control of electrical energy. The plasmas used in these devices usually have a low-charge density, and the fractional ionization is ordinarily less than one per cent. This small percentage of ionization is sufficient to provide good electrical conductivity which can be controlled externally, but it is difficult to study theoretically because of the numerous competing processes involving neutral atoms, metastable atoms, ions, electrons, and collective oscillations of ions and electrons

A Comparison of Delivery Methods of Cognitive-Behavioral Therapy for Panic Disorder: An International Multicenter Trial

Cognitive-behavioral therapy (CBT) is the psychological treatment of choice for panic disorder (PD). However, given limited access to CBT, it must be delivered with maximal cost-effectiveness. Previous researchers have found that a brief computer-augmented CBT was as effective as extended therapist-delivered CBT. To test this finding, this study randomly allocated 186 patients with PD across 2 sites in Scotland and Australia to 12 sessions of therapist-delivered CBT (CBT12), 6 sessions of therapist-delivered (CBT6) or computer-augmented CBT (CBT6-CA), or a waitlist control. On a composite measure, at post-treatment, the outcome for CBT12 was statistically better than the outcome for CBT6. The outcome for CBT6-CA fell between CBT12 and CBT6, but could not be statistically distinguished from either treatment. The active treatments did not differ statistically at 6-month follow-up. The study provided some support for the use of computers as an innovative adjunctive-therapy tool and merits further investigation

The Real (Social) Experience of Monetary Policy

This paper takes a socio-economic approach to considering money in relation to real experience, focusing on the real effects of monetary policy. While most of the economics literature focuses on interest-rate setting as the core tool of monetary policy, we focus here instead on signalling by the central bank as a mechanism for influencing expectations and behaviour in conditions of uncertainty. This involves addressing the social-conventional expectations among different groups (a mechanism for dealing with uncertainty) applied to their particular ways of framing the real and financial sectors. Actual credit conditions faced by borrowers in turn are the outcome of the conventional view among banks as a result of their framing and the influence of central bank signalling. These relations between central banks, banks and the non-bank public in turn normally rest on long-established relations of trust. We consider the real effects of monetary policy in circumstances where trust has broken down

A unified approach for the solution of the Fokker-Planck equation

This paper explores the use of a discrete singular convolution algorithm as a unified approach for numerical integration of the Fokker-Planck equation. The unified features of the discrete singular convolution algorithm are discussed. It is demonstrated that different implementations of the present algorithm, such as global, local, Galerkin, collocation, and finite difference, can be deduced from a single starting point. Three benchmark stochastic systems, the repulsive Wong process, the Black-Scholes equation and a genuine nonlinear model, are employed to illustrate the robustness and to test accuracy of the present approach for the solution of the Fokker-Planck equation via a time-dependent method. An additional example, the incompressible Euler equation, is used to further validate the present approach for more difficult problems. Numerical results indicate that the present unified approach is robust and accurate for solving the Fokker-Planck equation.Comment: 19 page

Exact solutions and stability of rotating dipolar Bose-Einstein condensates in the Thomas-Fermi limit

We present a theoretical analysis of dilute gas Bose-Einstein condensates with dipolar atomic interactions under rotation in elliptical traps. Working in the Thomas-Fermi limit, we employ the classical hydrodynamic equations to first derive the rotating condensate solutions and then consider their response to perturbations. We thereby map out the regimes of stability and instability for rotating dipolar Bose-Einstein condensates and in the latter case, discuss the possibility of vortex lattice formation. We employ our results to propose several novel routes to induce vortex lattice formation in a dipolar condensate.Comment: 12 pages with 6 figure

Theory of High-Tc Superconductivity: Accurate Predictions of Tc

The superconducting transition temperatures of high-Tc compounds based on copper, iron, ruthenium and certain organic molecules are discovered to be dependent on bond lengths, ionic valences, and Coulomb coupling between electronic bands in adjacent, spatially separated layers [1]. Optimal transition temperature, denoted as T_c0, is given by the universal expression $k_BT_c0 = e^2 \Lambda / \ell\zeta$; $\ell$ is the spacing between interacting charges within the layers, \zeta is the distance between interacting layers and \Lambda is a universal constant, equal to about twice the reduced electron Compton wavelength (suggesting that Compton scattering plays a role in pairing). Non-optimum compounds in which sample degradation is evident typically exhibit Tc < T_c0. For the 31+ optimum compounds tested, the theoretical and experimental T_c0 agree statistically to within +/- 1.4 K. The elemental high Tc building block comprises two adjacent and spatially separated charge layers; the factor e^2/\zeta arises from Coulomb forces between them. The theoretical charge structure representing a room-temperature superconductor is also presented.Comment: 7 pages 5 references, 6 figures 1 tabl

The Causal Structure of Emotions in Aristotle: Hylomorphism, Causal Interaction between Mind and Body, and Intentionality

Recently, a strong hylomorphic reading of Aristotelian emotions has been put forward, one that allegedly eliminates the problem of causal interaction between soul and body. Taking the presentation of emotions in de An. I 1 as a starting point and basic thread, but relying also on the discussion of Rh. II, I will argue that this reading only takes into account two of the four causes of emotions, and that, if all four of them are included into the picture, then a causal interaction of mind and body remains within Aristotelian emotions, independent of how strongly their hylomorphism is understood. Beyond the discussion with this recent reading, the analysis proposed of the fourfold causal structure of emotions is also intended as a hermeneutical starting point for a comprehensive analysis of particular emotions in Aristotle. Through the different causes Aristotle seems to account for many aspects of the complex phenomenon of emotion, including its physiological causes, its mental causes, and its intentional object