bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparative Study of on-off Characteristics of Conversational Bangla and English Speech Over a Telephone Channel
Authors: Rahman Saifur , Ahmed Kazi Mohiuddin 
Published: July 2017

A comparative study of on-off characteristics of conversational Bangla and English speech over a telephone channel The existing ‘speech interpolation’ technique used in some speech transmission systems has been developed for the English language. In order to explore the possibility that different settings of the parameters might be more appropriate for other languages, the on-off speech statistics of conversational Bangla speech over a telephone channel were collected. A comparative study of the on-off characteristics of Bangla and English speech is presented.
Experimental Self-Location Vehicle Based on Ultrasonic Waves Guided System
Authors: Habib Robert Sh. , Habib Harootyun Sh. , Majeed Bassam S. 
Published: July 2017

Experimental self-location vehicle based on an ultrasonic wave-guided system This paper describes the design and implementation of an automated guided vehicle, based on a microcomputer-controlled ultrasonic self-location system. Dynamic performance and system repeatability are evaluated by tests carried out on the applied self-navigating algorithm. The system is suitable for robotics or FMS laboratory experiments utilising the implemented hardware and relevant software.
PC-Based Protective Relaying Algorithms for Generator Using Digital Filters
Authors: Basha A. M. , Janardhanan P. , Bindu R. 
Published: July 2017

PC-based protective relaying algorithms for generator using digital filters Protective relaying algorithms are developed for extracting 50 Hz component of generator stator signals and 100 Hz component of rotor current signals. These frequency components are used for detecting the internal short-circuit and rotor overheating condition of generators. The proposed algorithms were satisfactorily tested for various simulated conditions of the system.
A Practical Introduction to Finite Element Analysis of Electromagnetic Problems
Authors: Chedid R. 
Published: July 2017

A practical introduction to finite element analysis of electromagnetic problems An attempt is made in this paper to bring the finite element method to a wider audience of undergraduate and graduate students through an approach that focuses on the design of the preprocessor, the solver and the postprocessor. Typical Fortran code is cited to illustrate the elegance of the method.
Generalized Machine Theory Applied to a Three Phase Twin Stator Squirrel-Cage Induction Motor
Authors: Perahia J. , Nayar C. V. 
Published: July 2017

Generalized machine theory applied to a three phase twin stator squirrel-cage induction motor This paper uses generalized machine theory to develop an equivalent circuit model of a three phase induction motor comprised of two independently housed stator windings with one stator housing moveable, and a single squirrel-cage rotor whose bars extend the full length of the two stators.
A Different Perspective of the Per-Unit System in Power System Engineering
Authors: Lee T. M. 
Published: July 2017

A different perspective of the per-unit system in power system engineering A novel method using per-unit admittance instead of the conventional per-unit impedance in power engineering is proposed. The use of one MVA as base power further reduces the computational process so that fault MVA at various parts of a network can be directly obtained by calculating the equivalent source admittances.
Rules for Designing Digital Controllers from their Analog Counterparts
Authors: O'malley Mark J. , Paor Annraoi M. De 
Published: July 2017

Rules for designing digital controllers from their analog counterparts Rules and observations for the design of balanced digital controllers from their analog counterparts are given. A root range technique showing the mapping of analog controller roots into the digital domain is illustrated. The performances of the digital control systems resulting from different emulation techniques are compared.
Simulation of a Fixed Pitch Wind Turbine Powered Induction Generator in EMTP
Authors: Perahia J. , Nayar C. V. 
Published: July 2017

Simulation of a fixed pitch wind turbine powered induction generator in EMTP Described are two models of a fixed pitch wind turbine drive train coupled to an induction generator compatible with the Electromagnetic Transients Program (EMTP). The models require wind speed or turbine torque changes. Model performance is studied on a 30 kW commercial arrangement.
A Spreadsheet Macro as a Teaching and Learning aid for Solving Electrical Networks
Authors: Eliahu M. , Ronen M. 
Published: July 2017

A spreadsheet macro as a teaching and learning aid for solving electrical networks The main method for solving electrical networks is based on matrix representation of the circuit. For any non trivial circuit this method is rather dfficult to follow since it involves a multi-stage solution procedure. This article describes a computerised environment, based on electronic spreadsheet macros, which was developed to facilitate the teaching and learning of solving electrical networks.
Comparison of Power Definitions in the Presence of Waveform Distortion
Authors: Eguiluz L. I. , Arrillaga J. 
Published: July 2017

Comparison of power definitions in the presence of waveform distortion In this paper, several definitions of reactive and apparent power in the non-sinusoidal regime are analysed and their repercussions in energy-billing are assessed. The classical method of optimisation by capacitor bank is considered to be problematic since it produces frequent resonances and increased harmonic distortion.
Pspice Modelling of Photovoltaic Arrays
Authors: Katan Ramzye. , Agelidis Vassilios G. , Nayar Chem V. 
Published: July 2017

PSPICE modelling of photovoltaic arrays A detailed model of a photovoltaic array written in PSPICE is presented in this paper. The powerful graphics post-processor that accompanies the software program is used to display array characteristics as a function of certain parameters such as insulation and temperature. Advantages include model capability to incorporate data taken from any commercially available solar panel. This is demonstrated in detail through a simple example.
Experiences with High-Level Design and Modelling of Digital Systems
Authors: Sangwine S. J. 
Published: July 2017

Experiences with high-level design and modelling of digital systems Design and modelling of digital systems has been taught at the University of Reading for six years, using Silvar-Lisco HELIX and lately IEEE Standard VHDL hardware description languages. Three exercises have been used throughout this time. These are: modelling of a multiplier-accumulator, design and modelling of a transversal filter, and specification-level modelling of a FIFO.
Matlab for Windows Software AID in a Mobile Communications Course
Authors: Fontan F. P. , Seoane A. , Castro M. V. 
Published: July 2017

Matlab for windows software aid in a mobile communications course A simple model for the teaching of land mobile communication channel issues has been implemented. The landscapes the mobile terminal traverses are described in terms screens, point scatterers, reflectors, etc. By using simple ray tracing techniques all multipath contributions arriving at the receiver are evaluated and the most relevant channel parameters are computed.
Endurance of Polyurethane Automotive Seating Foams under Varying Temperature and Humidity Conditions
Authors: Broos R. , Herrington R. M. , Casati F. M. 
Published: July 2017

The long-term comfort and durability properties of the flexible molded foams used in many forms of transportation seating are a subject of increasing interest to foam molders and seat producers. Existing and proposed new specifications for load bearing and other fatigue losses have necessitated a new look at the fundamental understanding of why foam properties change with temperature and humidity. In previous papers we have demonstrated the broad range of performance that can be expected from the well established and finely tuned chemistries (Hot Cure, TDI HR, MDI HR and TM-20 HR) currently used to make molded seating foams all around the world. Our focus turns now to a more fundamental study of the mechano-sorptive properties of these alternative foams in order to understand the mechanisms by which temperature and moisture cause changes in the foamed polymers. It was postulated that by knowing the exact sites of the water attack on the polymer, new ideas for improving important performance characteristics like wet compression set and tropical fatigue would arise. To get to the details of how temperature and moisture affect the mechanical response of a polyurethane network, we studied compression sets over a wide range of conditions and correlated those data with morphology changes obtained from spectroscopic studies and with traditional dynamic fatigue tests conducted in similar conditions. Additional insight into the reorganization of the polymer networks was gained from detailed analysis of the foam's dynamic mechanical performance under the influence of transient moisture conditions. We are now able to present a more comprehensive picture of the mechanisms behind the phenomena of wet compression set and tropical fatigue. This knowledge will be helpful to those striving to develop new raw materials and formulations for the next generation of transportation seating foams.
An Insight into the Characteristics of a Nucleation Catalyst in CFC-Free Rigid Foam Systems
Authors: Yoshimura H. , Tamano Y. , Okuzono S. , Lowe D. W. 
Published: July 2017

The establishment of CFC-free polyurethane foam systems, aimed at total CFC elimination by the year 1995, is of paramount importance in the present day polyurethane foam technology. Especially in rigid foam systems, the attempts to apply a variety of alternative blowing agents such as HCFC-22, -141b, and -142b, HFC-134a and -356, and hydrocarbons such as n-pentane, isopentane and cyclopentane, as well as all-water blown systems, are being examined. In all cases of alternative blown systems, however, there exist differences in foaming behavior as well as inferior foam properties compared to traditional CFC-11 blown systems. Especially in HCFC-141b and cyclopentane blown systems, which have gained the greatest interest among the above-mentioned options, the following three subjects are of major concern. The requirements involved in achieving the resolution of these problems are dependent not only on the development of major raw materials but also on the selection of suitable auxiliary intermediates such as catalysts and foam stabilizers. (1) Thermal Conductivity; HCFC-141b, cyclopentane and carbon dioxide, which is generated from the reaction of water and isocyanate, have high thermal conductivity compared to CFC-11, thereby causing inferior insulation performance of the foam. Fine cell technology is now being examined in order to improve the thermal conductivity. For the achievement of the fine cell structure, the selection of suitable amine catalyst systems is important, although the effect of foaming stabilizers has an especially large contribution. (2) Dimensional Stability; not only in all-water blown systems, but also in HCFC-141b and cyclopentane blown systems which use water in high concentration, dimensional stability becomes a large problem due to the diffusion of carbon dioxide gas from the foam cell. For the improvement of dimensional stability, there exists the option to increase the foam strength; moreover, it is important to improve the isotropy of cell structure by adjusting amine catalyst systems. (3) Foam density; since 141b and cyclopentane have relatively higher boiling points and less blowing efficiency, lowering the foam density becomes rather difficult. Moreover, lower foam density normally provides poor dimensional stability. It can be said that the catalytic activity ratio in blowing/gelling of amine catalysts play an important role for the lowering of foam density with improved dimensional stability. It is very difficult to improve these three factors simultaneously. In this report, however, the improvements of these subjects are discussed from a standpoint of amine catalysts; also special newly developed nucleation catalyst systems are introduced for cyclopentane and HCFC-141b blown systems.
Molecular Structure of the Hard Segments in Flexible Foams
Authors: Mertes J. , Stutz H. , Schrepp W. , Kreyenschmidt M. 
Published: July 2017

The main basis of structure-property-relationships of polymeric materials is a good characterization of the structure under study. Such is the case for cross linked polyurethanes such as flexible foams. To overcome the problems of solubility of these materials, a selective degradation process was used, leaving the hard segments unaffected. These were then analyzed by MALDI-TOF (Matrix Assisted Laser Desorption-Ionization Time of Flight mass spectrometry). Using these techniques, the length distribution of the hard segments was examined. It was found that the length of the hard segments decreases much slower for polyester foams than for polyether foams. This fact was attributed to a lower solubility of the hard segments in polyethers, which leads to an earlier onset of phase separation. Thus, both mobility and reactivity of the segments in the segregated hard domains are reduced. This fact also explains why the length of the hard segments is only slightly dependent on the water content, or the index, at least in polyether foams. Chemical differences such as the incorporation of polymeric MDI or reactive catalysts could also be shown. Furthermore, this work shows for the first time that presence of cyclic hard segments could be established in a foam.
Some Aspects of Matrix Formation of Flexible Polyurethane Foams
Authors: Falke P. , Kudoke C. , Rotermund I. , Zaschke B. 
Published: July 2017

The reaction of liquid raw materials like isocyanates, polyols, and water, to build a structural polymer network is a very complex sequence of different chemical reactions. We can describe some of these essential processes by the use of a dynamic measurement of the viscosity during the course of the foaming reaction, on-line FTIR-spectrometry measurements and the determination of the curing behaviour. We employed a laboratory FT-IR system, that was interfaced to an optical fibre loop. The formation of the soluble and associated urea species, the decay of isocyanate groups and the development of urethane species during the polymerization reaction were studied by FT-IR. The onset of the formation of associated urea species is influenced by the chemical composition of the reacting mixture. For the viscosity measurements we used a rotational viscosimeter. The network development was shown by the determination of the viscosity profile. By extrapolation of the course of the indentation force over time, estimated after the demould of the flexible foam, we determined the green strength of the moulding and the vitrification of the foam at a frozen morphology. We also illustrated the dependence of the mechanical properties of flexible PU foams on the chemical structures formed during the reaction.
Quantification of Parameters Influencing the Long-Term Dimensional Stability Performance of Pentane Blown Laminates
Authors: Baes M. , Galina C. , Vanlandschoot K. 
Published: July 2017

In view of the formulation changes induced by the use of alternative physical blowing agents, the understanding of the main parameters determining the dimensional stability performance was an important issue for the rigid laminate industry. So far, the influence of formulation and processing variables on dimensional stability has mainly been described qualitatively, and new evaluation techniques have been proposed in several publications. This paper describes how the application of the so-called dimvac test has led to a better quantification of the formulation and processing parameters influencing the long-term dimensional stability performance. A series of pentane blown laminates based on different formulations and processed on a variety of equipment were evaluated at the most severe condition in the dimvac test. We found that a set of formulation and processing requirements had to be fulfilled in order to ensure the dimensional stability of the laminates in service. The requirements were different for each formulation, production line and product. To quantify the influence of polyether polyol composition and type of non-reactive liquid fire retardant, a systematic laboratory study was carried out. For foams without fire retardant, a clear model was obtained predicting the dimvac performance in terms of foam density and polymer network parameters. For formulations including fire retardants, deviations from the model were observed, and differentiation between dilution and plasticization could be made.
A New Cell Opening Mechanism in Flexible Polyurethane Foam
Authors: Zhang X. D. , Davis H. T. , Macosko C. W 
Published: July 2017

Literature on the polyurethane foam cell opening mechanism is reviewed and discussed. A new cell opening mechanism is proposed. Cell opening is observed to be triggered by urea precipitation which changes the rheology of the polyurethane dramatically. The foam matrix shows extensional thinning behavior after urea phase separation. The extensional thinning behavior will lead to localized cell window thinning. The cell window thickness distribution will lead to different film rupture times for individual cell windows and will result in cell windows in different states. Some windows are totally missing and others leave torn-off films. Windows with only pin holes or totally closed were also observed. The cell opening event is shown to be a continuous process rather than a sudden event.
Roles of Conventional Polyol and Isocyanate in Humid Aging and Durability of Molded Seating Foam
Authors: Neff R. A. , Marsalko T. M. 
Published: July 2017

As the physical property requirements for molded seating foam increase in severity, the desired humid aged properties become more difficult to achieve. Thus a knowledge of the factors influencing these properties becomes increasingly valuable. This paper describes the initial part of a study into the effects of conventional polyol and isocyanate structures on the durability and humid aging of flexible molded foam. A series of conventional polyols was synthesized and evaluated in an all-TDI molded foam formulation (32 kg/M3 density), with emphasis on compression set, dynamic fatigue (constant force pounding) and humid aging. FTIR was used to measure the effect of humid aging on the hard domain microstructure. The compression set data suggest that increasing the polyol ethylene oxide (EO) cap (endblock) size accelerates humid aging, and the overall EO content (including EO added randomly to the internal block) is important to longer term humid aging (such as during the "wet set" test). The effects of nominal functionality, equivalent weight and unsaturation (monol) content were also measured. Dynamic fatigue (hardness loss) increased with the amount of cross linking in the foam, which increases with decreasing equivalent weight, decreasing unsaturation level and increasing functionality. Humid aging had little effect on the dynamic fatigue. Additionally, several different isocyanates (including monomeric MDI, a modified monomeric MDI and polymeric MDI) were evaluated in a similar molded foam formulation. This series of foams was subjected to alternating cycles of humid aging and pounding, and a series of physical properties was measured following each cycle. The sensitivities of peak tensile and wet compression set to the amount of humid aging and fatigue correlated with the type of isocyanate. Higher isocyanate functionality decreased sensitivity to humid aging, due to formation of a permanent covalently bound network. Humid aging sensitivity was also affected by the packing behavior of the urea hard domains, which is controlled by the isocyanate structure. The effect of isocyanate on hard domain microstructure is further illustrated using dynamic mechanical thermal analysis (DTMA).
Temporal Patterns of Cognitive Activity and Breath Control in Speech
Authors: Henderson Alan , Goldman-Eisler Frieda , Skarbek Andrew 
Published: July 2017

Two aspects of spontaneous speech, the cognitive and the syntactic, were examined as potential regulators of the incidence of breathing during speech. During passages of prose read aloud breaths were taken exclusively at gaps in speech designated as grammatical junctures. During samples of spontaneous speech approximately one third of the breaths were taken at gaps in speech which could not be so described. The sequential temporal structuring of spontaneous speech reveals passages which appear principally to be given over to decisions about content alternating with fluent passages which appear to be the product of the preceding passage. Passages primarily characterised by cognition have a significantly lower proportion of breaths taken at grammatical junctures than the more fluent passages.
Controls for the Size Box
Authors: Yelland William E. 
Published: July 2017

( 1) Closer automatic control of size box temperature is ob tained when the size level is also controlled automatically. (2) In small shallow size boxes, such as exist on certain rayon slashers, the size level can be controlled more effectively by an elec trical contact rather than by the use of devices depending on size temperature. (3) When level or temperature controls are installed in a size box the surface of the control exposed to the size should be composed of a metal as nearly like that of the lining of the size box as pos sible; otherwise, corrosion—due to electrolytic action set up by dis similar metals in close contact with each other and immersed in the hot size liquor—may cause serious difficulties.
One-Step Wet-Fixation Deposition Process for Cotton Using Low Add-Ons of Resin
Authors: Vail Sidney L. , Verburg Gerald B. , Young Alvin H. P. , Parikh D. V. 
Published: July 2017

An improved process for precure or postcure durable-press, colored cotton fabrics has been developed through the pilot-plant stage. In an efficient use of reagents, resins are deposited or fixed in the swollen cotton fiber and then cured to produce a highly wrinkle-resistant fabric with a minimum of strength and abrasion losses. The steaming, under drying conditions, of fabric impregnated with melamine resins and a cross-linking agent at pH 3.5–6 provides the necessary deposition and “fixation” reaction. Curing of the steamed fabric completes the polymerization and cross-linking required for the process. Details are presented which were selected to assist in the commercialization of this process. It is believed the degrees of freedom available in the steaming conditions and choice of reagents and acidity are general enough to assure a successful scale-up.