Measuring One Aspect of Teachers’ Affective States: Development of the Science Teachers’ Pedagogical Discontentment Scale

The aim of this research is to describe the development of the Science Teachers’ Pedagogical Discontentment Scale, an instrument that measures the discontentment that arises in teachers as they recognize a mismatch between their own pedagogical beliefs and goals and their actual classroom practices. From a conceptual change perspective, we explore the meaning of pedagogical discontentment and discuss its role in shaping teachers’ receptivity to messages of reform. We present an instrument that can be used to measure teachers’ pedagogical discontentment, an instrument that will allow science educators to better describe the affective states of teachers as they enter professional development experiences. The items for the initial instrument were derived from a series of interviews with practicing teachers; from these interviews, a group of 42 items were designed around a group of five subscales. The final instrument, revised after two rounds of field testing, includes 21 multiple‐choice items clustered around six subscales (subscales derived from interviews with science teachers). The processes used to develop the items and to refine instrument are discussed. Uses for this instrument to inform professional development experiences are explored as well as implications.     

Metal oxides composite electrode with high areal capacitance formed by thermal oxidation of stainless steel mesh

Journal of Solid State Electrochemistry - The motivation of this study is to understand the usability of annealed stainless steel mesh obtained by a straightforward method for energy storage...     

Generation of a single-cycle optical pulse

We make use of coherent control of four-wave mixing to the ultraviolet as a diagnostic and describe the generation of a periodic optical waveform where the spectrum is sufficiently broad that the envelope is approximately a single-cycle in length, and where the temporal shape of this envelope may be synthesized by varying the coefficients of a Fourier series. Specifically, using seven sidebands, we report the generation of a train of single-cycle optical pulses with a pulse width of 1.6 fs, a pulse separation of 11 fs, and a peak power of 1 MW.     

Quasiperiodic Raman technique for ultrashort pulse generation

We report the experimental demonstration of a new Raman technique that produces 200 sidebands, ranging in wavelength from 3 microm to 195 nm. By studying multiphoton ionization of nitric oxide (NO) molecules, we show mutual phase coherence among 15 visible sidebands covering 0.63 octaves of bandwidth.     

An investigation of electrorheological properties of calcium carbonate suspensions in silicone oil

In this study, electrorheological behavior of suspensions prepared from 0.9 and 5.0 µm calcium carbonate particulates, dispersed in insulating silicone oil medium was investigated. Sedimentation stabilities of suspensions (c = 5 wt %) prepared using these calcium carbonate powders were determined to be 6 and 4 days, respectively. Electrorheological activity of all the suspensions was observed to increase with increasing electric field strength, concentration and decreasing shear rate. Shear stress of calcium carbonate suspensions increased linearly with increasing concentrations of the particles and with the applied electric field strength. Electric field viscosity of all the suspensions was decreased sharply with increasing shear rate and particle size, showing a typical shear thinning non-Newtonian visco-elastic behavior. Effects of elevated temperature and polar promoter onto electrorheological activity of calcium carbonate/silicone oil system were also investigated.__________From Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 268–273.Original English Text Copyright © 2005 by Yilmaz, Ünal, Yavuz.This article was submitted by the authors in English.     

4‐Methylcarbazole‐3‐carboxylic acid

The title compound, C₁₄H₁₁NO₂, consists of a carbazole skeleton with carboxyl­ic acid and methyl groups at positions 3 and 4, respectively. Molecules are linked about inversion centres by O—H?O hydrogen bonds [O?O 2.620 (3) Å] to form centrosymmetric dimers.     

Threshold start-up control policy for polling systems

A threshold start-up policy is appealing for manufacturing (service) facilities that incur a cost for keeping the machine (server) on, as well as for each restart of the server from its dormant state. Analysis of single product (customer) systems operating under such a policy, also known as the N-policy, has been available for some time. This article develops mathematical analysis for multiproduct systems operating under a cyclic exhaustive or globally gated service regime and a threshold start-up rule. It pays particular attention to modeling switchover (setup) times. The analysis extends/unifies existing literature on polling models by obtaining as special cases, the continuously roving server and patient server polling models on the one hand, and the standard M/G/1 queue with N-policy, on the other hand. We provide a computationally efficient algorithm for finding aggregate performance measures, such as the mean waiting time for each customer type and the mean unfinished work in system. We show that the search for the optimal threshold level can be restricted to a finite set of possibilities. This revised version was published online in June 2006 with corrections to the Cover Date.     

Formulation of electro-chemico-osmotic processes in soils

Electrokinetic techniques have been used for various purposes including consolidation of soils, dewatering of sludges, and hazardous waste remediation among others. Estimating the feasibility of employing electro-osmosis in a particular operation depends on the ability to predict the outcome under a variety of conditions. Predictions of this type are frequently facilitated by the use of a mathematical model designed to represent the physical system under consideration in a rigorous fashion. First, a review of fundamental aspects of electro-chemico-osmotic flow in soils is presented. Following a brief outline of previous studies, identification and quantification of the significant processes, and the construction of mathematical representations are given. This is achieved using an approach based on the macroscopic conservation of mass equations and the principle of a continuum, in contrast to an approach based on the irreversible thermodynamics of coupled flows. Special emphasis is given to coupling effects on transport processes. A complete model and associated boundary conditions are then obtained for electrokinetic processes in a compressible porous medium. The proposed model takes into consideration the migration of a contaminant plume in a flow field generated by an applied electric potential.Symbols a _v soil compressibility - A an entity - C _w mass fraction of water component in the water phase - C _s mass fraction of chemical component in the water phase - C ^* capacitance of the porous medium per unit volume of porous volume - D mechanical dispersion coefficient - D _fw ^ps hydrodynamic diffusion tensor for the chemical component in the water phase - D _fw ^pw hydrodynamic dispersion coefficient for the water component in the water phase - D _f( )/Dt material derivative with respect to an observer moving at the water phase velocity V _f - D _s( )/Dt material derivative with respect to moving solids - e void ratio - f a function - F = 0 equation of a moving boundary - g gravitational acceleration - k permeability tensor of the porous medium - k _e coefficient of electro-osmotic permeability - k _ec coefficient of migration potential - k _hc chemico-osmotic coupling coefficient - m _i number of moles of the ith component - m _i0 number of moles of the ith component at a reference level - n porosity - p pore pressure - p _oi pore pressure at a reverence level - q specific discharge of water phase - q _e current density - q _fe ^p0 constant current density applied at a boundary - q ₀ constant flow rate - q _r specific discharge of the water phase relative to the moving solid matrix - R net mass transfer rate of the chemical component in the water phase - t time - u velocity of a moving surface - _i partial molar density of ith component - V _f velocity of the water phase - V _s velocity of the solid (rate of deformation) - x vertical coordinate - coefficient of matrix compressibility - _p compressibility of water phase in motion - total (overburden) stress tensor - effective stress tensor - _h streaming current conductivity - _e electrical conductivity - electrical potential - _f viscosity of the water phase - _hf density of the water phase     

Generalized difference sequence spaces on seminormed space defined by Orlicz functions

In this paper we define the sequence space ℓ _M (Δ ^m , p, q, s) on a seminormed complex linear space by using an Orlicz function. We study its different algebraic and topological properties like solidness, symmetricity, monotonicity, convergence free etc. We prove some inclusion relations involving ℓ _M (Δ ^m , p, q, s).      

Application of electrochemically generated molybdenum‐based catalyst system to the ring‐opening metathesis polymerization of norbornene and a comparison with the tungsten analogue

This study describes the application of the electrochemically generated molybdenum‐based catalyst system MoCl₅? e^?? Al? CH₂Cl₂ to ring‐opening metathesis polymerization of bicyclo[2.2.1]hept‐2‐ene (norbornene). The results are compared with those previously obtained by the WCl₆? e^?? Al? CH₂Cl₂ system. The polymer product has been characterized by ¹H and ¹³C NMR, IR and gel‐permeation chromatography techniques. This molybdenum‐based catalyst system has led to a mainly trans stereoconfiguration (ca 60%) of the double bonds, in contrast to the polymer obtained with the tungsten‐based analogue, where the cis content is 60%. Analysis of the poly(1,3‐cyclopentylenevinylene) microstructure by ¹³C NMR spectroscopy revealed that the polymer having σ_c = 0.41 (fraction of double bonds with cis configuration) contains a slightly blocky distribution (r_tr_c > 1) of the double‐bond dyads (r_tr_c = 1.44). In addition, the influence of reaction parameters, e.g. reaction time, electrolysis time and catalyst aging time, on conversion has been analysed in detail. Copyright © 2005 John Wiley & Sons, Ltd.