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Cyclotron motion of a charged particle with anisotropic mass
No full textThe cyclotron motion of a charged particle subject to a uniform magnetic field is thoroughly described in many classical physics textbooks. Although the assumption of a particle with isotropic mass is taken for granted in classical physics, a key concept in condensed matter physics is that of particles with an effective anisotropic mass, such as electrons in the context of band structure studies of solids. Since some exposure to the concept of anisotropic mass is important within the framework of classical physics, here we consider the cyclotron motion of a charged particle with anisotropic mass in the presence of a uniform magnetic field. The exact solution of this problem exposes a broad audience of readers to concepts in condensed matter physics that are rarely mentioned within the framework of classical physics. Key ideas on the topic are illustrated in a pedagogical way by considering specific examples that show how an anisotropic mass modifies the cyclotron motion of a charged particle
Successes and failures in building learning environments to promote deep learning: The value of conversational agents
No full textThis chapter describes some attempts to promote deep learning (as opposed to shallow learning) through conversational pedagogical agents. Learning environments with agents have been developed to serve as substitutes for humans who range in expertise from novices to experts. For example, AutoTutor helps students learn by holding a dialogue in natural language with the student, whereas trialogues have two agents interacting with the student in a three-way interaction. Agents can guide the interaction with the learner, instruct the learner what to do, and interact with other agents to model ideal behavior, strategies, reflections, and social interactions. Some agents generate speech, gestures, body movements, and facial expressions in ways similar to people. These agent-based systems have sometimes facilitated deep learning more than conventional learning environments. Agents have shown learning gains on a variety of subject matters and skills, including science, technology, engineering, mathematics, research methods, metacognition, and language comprehension. Learning environments are currently being developed to improve lifelong learning and collaborative problem solving
On (Semi)Topological BCC-algebras
Get PDFIn this paper, we introduce the notion of (semi)topological BCC-algebras and derive here conditions that imply a BCC-algebra to be a (semi)topological BCC-algebra. We prove that for each cardinal number α there is at least a (semi)topological BCC-algebra of order α: Also we study separation axioms on (semi)topological BCC-algebras and show that for any infinite cardinal number α there is a Hausdorff (semi)topological BCC-algebra of order α with nontrivial topology
Two dimensional kinematic surface in Lorentz-Minkowski 5-space with constant scalar curvature
Get PDFIn this paper we analyzed the problem of investigating locally the scalar curvature of the two dimensional kinematic surfaces foliated by the homothetic motion of an eight curve in Lorentz-Minkowski 5-space Ls. We express the scalar curvature of the corresponding two dimensional kinematic surfaces as the quotient of hyperbolic functions {sinh mv, cosh mv }. From that point, we derive the necessary and sufficient conditions that the coefficients of hyperbolic functions vanished identically. Additionally, an example is given to show two dimensional kinematic surfaces with constant scalar curvature
Effect of Buoyancy and Magnetic Field on Unsteady Convective Diusion of Solute in a Boussinesq Stokes Suspension Bounded by Porous Beds
Get PDFHydromagnetic free and forced convection in a parallel plate channel bounded by porous bed and transverse magnetic field has been considered. When there is a uniform axial temperature variation along the walls, the primary flow shows incipient flow reversal at the upper plate for an increase in temperature along that plate. Similarly flow reversal at the lower plate occurs with a decrease in temperature along that plate. The magnetic field, arising as a body couple in the governing equations is shown to increase the axis dispersion coefficient. The effect of various physical parameters such as Hartmann number, Grashof number, porous parameter and couple stress parameter on the velocity, temperature and dispersion coefficient, mean concentration, skin friction coefficient and Nusselt numbers are computed and analyzed through graphs
Some properties of certain mixed type special matrix functions and polynomials
Get PDFBy using certain operational methods, the authors introduce some new mixed type special matrix functions and polynomials. Some properties of these matrix functions and polynomials are established
Analysis of a M/M/c queue with single and multiple synchronous working vacations
Get PDFWe consider a M/M/c queuing system with synchronous working vacation and two different policies of working vacation i.e. a multiple working vacation policy and a single working policy. During a working vacation the server does not completely halts the service rather than it will render service at a lower rate. In synchronous vacation policy all the servers leave for a vacation simultaneously, when the server finds the system empty after finishing serving a customer. In multiple working vacation (MWV) policy the servers continue to take vacation till they find the system nonempty at a vacation completion instant. Single working vacation (SWV) policy is different from the multiple working vacation policy in a way that, when the working vacation ends and servers find the system empty, they remains idle until the first arrival occurs rather than taking another vacation. We have derived explicit expressions for some performance measures in terms of two indexes by using PGF method. We derived some results regarding the limiting behavior of some performance measures based on these two indexes. A comparison between the models is carried out and numerical results are provided to illustrate the effects of various parameters on system performance measures
Hückel theory + reorganization energy = Marcus-Hush theory: Breakdown of the 1/n trend in π-conjugated poly-p-phenylene cation radicals is explained
No full textAmong the π-conjugated poly-p-phenylene wires, fluorene-based poly-p-phenylene (FPPn) wires have been extensively explored for their potential as charge-transfer materials in functional photovoltaic devices. Herein, we undertake a systematic study of the redox and optical properties of a set of FPPn (n = 2-16) wires. We find that, while their absorption maxima (νabs) follow a linear trend against cos[π/(n + 1)] up to the polymeric limit, redox potentials (Eox) show an abrupt breakdown from linearity beginning at n ∼ 8. These observations prompted the development of a generalized model to describe the unusual evolution of redox and optical properties of poly-p-phenylene wires. We show that the cos[π/(n + 1)], commonly expressed as 1/n, dependence of the properties of various π-conjugated wires has its origin in Hückel molecular orbital (HMO) theory, which however, fails to predict the evolution of the redox potentials of these wires, as the oxidation-induced structural/solvent reorganization is unaccounted for in the original formulation of HMO theory. Accordingly, aided by DFT calculations, we introduce here a modified HMO theory that incorporates the reorganization energy (Δα) and coupling (β) and show that the modified theory provides an accurate description of the oxidized FPPn wires, reproducing the breakdown in the linear cos[π/(n + 1)] trend. A comparison with the Marcus-based multistate model (MSM), where reorganization (λ) and coupling (Hab) are introduced by design with the aid of empirically adjusted parameters, further confirms that the structural/solvent reorganization limits hole delocalization to ∼8 p-phenylene units and leads to the breakdown in the linear evolution of the redox properties against cos[π/(n + 1)]. The predictive power of the modified HMO theory and MSM offer new tools for rational design of the next-generation, long-range charge-transfer materials for photovoltaics and molecular electronics applications. (Graph Presented)
The information Systems artifact: A conceptualization based on general systems theory
No full textPassionate debates regarding the defining characteristic of the “IT artifact” continue. Such debates, and also the lack of explicit consideration of the “information” element in the IT artifact, motivate us to propose a revised conception, drawing upon concepts from General Systems Theory (GST). Following a number of scholars [39], we name our reconceptualization as an IS artifact, which aims to provide a contemporary view of an IS that could accommodate the changing nature of both society and technology while at the same time maintain a clear definition of what we mean by an IS
Using the control balance theory to explain online social media deviance
No full textOnline Social Media Deviance (OSMD) is one the rise; however, research in this area traditionally has lacked a strong theoretical foundation. Following calls to reveal the theoretical underpinnings of this complex phenomenon, our study examines the causes of OSMD from several novel angles not used in the literature before, including: (1) the influence of control imbalances (CIs) on deviant behavior, (2) the role of perceived accountability and deindividuation in engendering CI, (3) and the role of IT in influencing accountability and deindividuation. Using an innovative factorial survey method that enabled us to manipulate the IT artifacts for a nuanced view, we tested our model with 507 adults and found strong support for our model. The results should thus have a strong impetus not only on future SM research but also for social media (SM) designers who can use these ideas to further develop SM networks that are safe, supportive, responsible, and constructive