Turned trochoidal disturbance on a liquid jet surface

This paper shows that a turned trochoidal function disturbance may lead to peripheral drops production. The resulting model is used to describe that a turned trochoidal disturbance leads to peripheral drops production on the liquid jet surface without the necessity for superimposed disturbances. The trochoid is a non-unique parametric function. Only non-unique parametric functions disturbances may lead to peripheral drops production. The trochoidal function disturbance is decomposed to Fourier series. Every Fourier element receives an amplification factor in accordance to the Rayleigh inviscid jet model. Peripheral drops are received on the jet surface. The paper shows that all trochoidal disturbance functions, prolate cycloid, cycloid and curtate cycloid have a capability of peripheral drops producing. A limited capability of peripheral drops production is introduced for the trochoidal curtate cycloid. Produced drops size are reduced for increasing the jet velocity and wave number. Smaller drops are also received by transition from the prolate cycloid to curtate cycloid disturbance.     

Teacher beliefs and technology integration practices: A critical relationship

Early studies indicated that teachers’ enacted beliefs, particularly in terms of classroom technology practices, often did not align with their espoused beliefs. Researchers concluded this was due, at least in part, to a variety of external barriers that prevented teachers from using technology in ways that aligned more closely with their beliefs. However, many of these barriers (access, support, etc.) have since been eliminated in the majority of schools. This multiple case-study research was designed to revisit the question, “How do the pedagogical beliefs and classroom technology practices of teachers, recognized for their technology uses, align?”     

A Bound for the Order of Characteristic Set Elements of an Ordinary Prime Differential Ideal and some Applications

With respect to an elimination ordering, we give an upper bound for the order of characteristic set elements of an ordinary prime differential ideal. Using some results of complexity in the algebraic case, we show that computing characteristic sets of ordinary prime differential ideals, by change of ordering, is single exponential time. Received: January 8, 1997; revised version: May 6, 1999     

Effect of the host polymer on the nanomechanical and morphological properties of templated polymer films

Atomic force microscopy and nanoindentation have been applied to the study of thin molecularly templated polymer films. The template was chosen to be the readily hydrogen‐bonded cotinine molecule and three different polymer hosts, Elvamide® nylon, Nylon‐6, and poly(4‐vinylphenol) were compared. The host polymer was shown to affect the nature of the template‐host interaction resulting in varying surface morphologies and differences in the nanohardness. These observations were shown to reflect differences in the underlying interaction chemistry, specifically, whether or not the polymer may be imprinted in the film production process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 877‐883, 2013     

Radical grafting of polar monomers onto polypropylene by reactive extrusion

Polypropylene (PP) was functionalized in the melt by grafting polar monomers using an internal mixer and a corotating twin‐screw extruder. 2,5‐Bis(tertbutylperoxy)‐2,5‐dimethylhexane (Luperox 101) and dicumyl peroxide (DP) were the used radical initiators. The polar monomers were itaconic acid (IAc), 2‐octen‐1‐ylsuccinic anhydride (OY), 2‐hydroxyethyl methacrylate (HEMA), and 3‐allyloxy‐1,2‐propanediol (AP). Grafting was quantified by FTIR combined to Elemental Analysis. Grafting degree depends mainly on monomer and initiator natures and concentrations. Grafting degree maxima were 3.9, 2, 9.5, and 3.9 wt %, respectively, for IAc, OY, HEMA, and AP. Some properties of the modified PP were evaluated. Thermal analysis indicated that the polarity of PP increased by grafting reaction and size‐exclusion chromatography showed that the grafting was not accompanied by a significant M_w and viscosity decrease. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

POWER-Area-Performance Characteristics of FPGA-based Sigma-Delta FIR Filters

While one-bit ΣΔ modulators are widely used in Analog to Digital conversion stages due to their inherent linearity and precision, it is less common for the entire digital processing path to operate in single bit mode at the oversampled rate of the conversion system. The conventional approach has been to decimate the signal bit stream after conversion and for the remaining processing to be performed in standard multi-bit binary at the Nyquist rate and with a resolution mandated by the dynamic range and noise. Using a Finite Impulse Response filter design as an example, we compare the area and performance of this conventional approach with the alternative single bit approach that operates directly on the ΣΔ data stream using ternary coefficients {?1, 0, +1} derived from the ΣΔ modulation of the target impulse response. Filters exhibiting approximately equivalent spectral performance in the two alternative approaches were developed using VHDL and simulated using some commercial FPGA types. In these experiments, the single-bit filters using ternary coefficients were found to dissipate less power compared to the conventional approach despite their need to operate at much higher clock rates. They also exhibit up to 40% higher performance and offer useful area savings at lower filter orders. At higher orders, the ΣΔ approach retains its power and performance advantages but exhibits slightly higher chip area. The simplicity and low power of the ΣΔ approach makes it applicable to mobile communication processing using low cost FPGA technology.     

A colloidal method for manganese oxide addition to alumina powder and investigation of properties

Various methods can be applied to introduce additives to ceramic materials. Of these methods, mechanical mixing may not always be suitable to obtain a uniform distribution of the small quantities of additive within the structure, requiring colloidal methods to be applied for the purpose. The addition of manganese oxide to alumina powder has been studied using a colloidal method. The effect of the manganese addition on alumina microstructure and the later stages of the densification behaviour was investigated, together with the hardness and mechanical strength. No evidence of secondary phase formation was detected between the manganese cation and alumina powder for up to 0.5wt% manganese addition, suggesting that manganese is in solid solution with alumina. The microstructural evidence presented suggests that small quantities of a manganese addition to alumina enhance the densification process through the formation of fast diffusion paths within the crystalline structure, similar to the effect of TiO₂ addition.     

Numerical and experimental analysis of unsteady heat transfer with periodic variation of inlet temperature in circular ducts

This work focusses on a numerical and experimental analysis of unsteady forced convection in hydrodynamically developed and thermally developing laminar air flow in a circular duct, subjected to a periodic variation of the inlet temperature. The experiments were conducted over a wide range of Reynolds number (281.2 ≤ Re ≤ 1024.3) and inlet frequency (0.01 ≤ β ≤ 0.20 Hz) of the periodic heat input. In the numerical study, the non-uniform inlet temperature amplitude profile derived from the experiments, was included in the numerical model. A fully explicit, second-order accurate finite difference scheme was developed and used for the solution of the unsteady energy equation. Numerical results are obtained with the fully developed parabolic velocity profile under the boundary condition of the first kind, which was verified by the experiments. Temperature variations along the centerline of the circular duct are observed to be thermal oscillations with the same frequency as the inlet periodic heat input and amplitudes that decayed exponentially with distance along the duct. Thermal response along the wall exhibits negligible amplitude variation with changes in Reynolds number and inlet frequency. The variation in the periods and amplitudes of the thermal oscillations are observed to be a function of spacial system variables only. Satisfactory agreement between the numerical and experimental results are obtained.     

Low-frequency electrophoretic actuation of nanoscale optoentropic transduction mechanisms

Inherent bistabilities within DNA-assembled fluorescent resonant energy transfer systems demonstrated time-varying optical signals in response to an electrophoretic driving force. Frequency responses of electrophoretically driven FRET systems were shown to be sequence specific. Integration of these signals over time gave near single-molecule sensitivity within a high background of autofluorescence. This research suggests that externally driven nanoscale mechanical systems may help improve information flow within morphologically intact specimens.     

A new supervised classification algorithm in artificial immune systems with its application to carotid artery Doppler signals to diagnose atherosclerosis

Because of its self-regulating nature, immune system has been an inspiration source for usually unsupervised learning methods in classification applications of Artificial Immune Systems (AIS). But classification with supervision can bring some advantages to AIS like other classification systems. Indeed, there have been some studies, which have obtained reasonable results and include supervision in this branch of AIS. In this study, we have proposed a new supervised AIS named as Supervised Affinity Maturation Algorithm (SAMA) and have presented its performance results through applying it to diagnose atherosclerosis using carotid artery Doppler signals as a real-world medical classification problem. We have employed the maximum envelope of the carotid artery Doppler sonograms derived from Autoregressive (AR) method as an input of proposed classification system and reached a maximum average classification accuracy of 98.93% with 10-fold cross-validation method used in training-test portioning. To evaluate this result, comparison was done with Artificial Neural Networks and Decision Trees. Our system was found to be comparable with those systems, which are used effectively in literature with respect to classification accuracy and classification time. Effects of system's parameters were also analyzed in performance evaluation applications. With this study and other possible contributions to AIS, classification algorithms with effective performances can be developed and potential of AIS in classification can be further revealed.