bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the fire‐retardant properties of new modifiers in unsaturated polyester resins using the cone calorimetric method
Authors: Kicko‐Walczak Ewa 
Published: October 2003

AbstractAn investigation of the burning behaviour of a series of unsaturated polyester resin formulations has been carried out using the Cone calorimeter technique. A complex analysis of the pyrolysis of selected glass‐reinforced polyester (GRP) laminates was made based on fire‐nonretarded, fire‐retarded and smoke suppressed compositions of unsaturated polyester resins (UPR) by the use of mixtures of zinc hydroxystannate ZnSn(OH)6, (ZHS), zinc stannate ZnSnO3 (ZS) and zinc borate or zinc molybdate. The heat release (average) rate (HRR and HRRav), time required to ignite a GRP, the mass loss rate and (average) surface extinction area (SAE and SAEav) were studied in relation to thermal irradiation power and to presence or absence of a fire retardant. The cone calorimeter is shown to enable all the stages of pyrolysis of GRP involving combustion and smoke emission to be analyzed, and confirmed the good effects of Zn/Sn systems as a fire retardant additives for UPR.
Surface modified aluminium hydroxide in flame retarded noise damping sheets
Authors: Keszei Sándor , Anna Péter , Marosi Györgi , Márton Andrea , Bertalan Györgi , Valló Ferenc 
Published: October 2003

AbstractFlame retarded polyethylene compounds were prepared using a series of aluminium hydroxide of different particle size applying a milling processes and special precipitation technologies. The processability and flame retardant efficiency of the flame retarded systems were compared. The effects of various surface modifications were analysed in case of one selected type of aluminium hydroxide. A silicone terminated reactive surfactant promoted not only the processability but also the flame retardant efficiency. Noise damping sheets were prepared by simultaneous application of aluminium hydroxide and barium sulphate in an elastomer blend matrix. V0 flame retardant grade could be achieved this way accompanied with improvement in the acoustic properties and maintenance of the mechanical properties.
Surface treated cellulose fibres in flame retarded PP composites
Authors: Anna P. , Zimonyi E. , Márton A. , Szép A. , Matkó Sz. , Keszei S. , Bertalan Gy. , Marosi Gy. 
Published: October 2003

AbstractPolypropylene‐based composites were prepared containing non‐treated and various treated cotton fibre and wood flakes. A correlation was observed among the fibre treatment and compounding parameters, mechanical and discoloration properties. The structural changes in fibres were demonstrated by Raman spectroscopic and DSC measurements. The possibility for forming cellulose fibre containing flame retardant composites was also investigated. The efficiency of various treatments on compounding, discoloration and mechanical properties enhance in the following order: no treatment < non ionic surfactant < reactive silicone segment containing non ionic surfactant < special silylation treatment. The best results obtained with the special silylation treatment were explained with the more organophilic character and by the thermal stability of the treated fibres. Cellulose fibre as a polyol‐charring component and ammonium‐polyphosphate together constitute a high performance intumescent flame retardant system in the PP matrix.
Use of reactive surfactants in basalt fiber reinforced polypropylene composites
Authors: Matkó Sz. , Anna P. , Marosi Gy. , Szép A. , Keszei S. , Czigány T. , Pölöskei K. 
Published: October 2003

AbstractBasalt fibers, similarly to other silicate fibers, can be introduced into both thermoplastic and thermosetting polymer matrices. In this work some basalt fiber reinforced polypropylene composites were investigated. The fiber‐matrix adhesion was improved by commercial and non‐commercial maleic anhydride derivatives. The latter types, called reactive surfactants, were prepared in laboratory scale and the progress of the syntheses was determined by Raman microscopy. The additives allowed performing reactive interface modification during the compounding process. Due to the interface modification with the additives in low concentration the mechanical properties improved. The boundary layers on the surface of the reinforcing fibers were observed using scanning electron microscopy (SEM).
Analysis of multicomponent polymer systems by raman microscopy
Authors: Szép A. , Marosfői B. , Bertalan Gy. , Anna P. , Marosi Gy. 
Published: October 2003

AbstractThe Raman microscope is one of the most convenient instruments for analyzing the structural characteristics and changes in the interfacial region of multicomponent systems. This is confirmed by the results obtained in the field of packaging materials, nanocomposites, and basalt fibre reinforced composites. In the course of this study, the chemical character of the surface and interfacial regions were investigated and, in addition, the local characteristics of the crystallization process of the polymer matrix could be determined.
Aging of silica‐filled PDMS/PDPS copolymers in desiccating environments: a DSC and NMR study
Authors: Maxwell Robert S. , Balazs Bryan , Cohenour Rebecca , Prevedel Elizabeth 
Published: October 2003

AbstractThe involvement of water in the reinforcing mechanism in silica‐filled polydimethylsiloxane (PDMS) based composite systems, potentially leaves the polymer composite susceptible to mechanical property changes when exposed to desiccating environments. We have studied the effects of thermal and chemical desiccation on a silica filled PDMS/PDPS copolymer system by DSC and NMR analysis. Our results show that as the polymer was desiccated, segmental dynamics in the polymer network were reduced significantly and changes in melt heats of fusion and stress relaxation were observed. NMR 1H relaxation measurements have measured a change in 1H T2e of 30% after storage in desiccating environments longer than 1 year. The experimental data presented argue that the reduced mobility of the PDMS chains in the interfacial domain after desiccation reduced the overall, bulk, motional properties of the polymer, thus causing an effective “stiffening” of the polymer matrix.
Weak flocculation of aqueous kaolin suspensions initiating by NaCMC with different molecular weights
Authors: Li Y. , Nagy É.S. , Esmail M.N. , Hórvölgyi Z. 
Published: October 2003

AbstractThe present work is an investigation of the effect of NaCMC with different viscosities (molecular weights) on the stability of aqueous kaolin suspensions at pH 5‐6. The stabilizing effect of polymers was characterized by measuring the sedimentation volumes (for 2.5% kaolin suspensions) and some important rheological parameters (for 40% and 50% kaolin suspensions). In certain cases the stability of suspensions was also studied in the presence of 0.5‐1.0% NaCl. The additives were incorporated into the suspensions separately and simultaneously, as well. In certain cases the effect of mixing order of NaCMCs was also studied. The lower viscosity NaCMC was found to be a better stabilizing agent than its medium viscosity counterpart at the studied polymer concentrations (0.005‐1.0%). This was manifested in smaller sedimentation volumes and lower rheological parameters (viscosity, yield stress, degree of thixotropy and elasticity). The lower and the medium viscosity polymer were simultaneously and consecutively added in a mass ratio of 50:1 and 10:1. The resulted observation of low viscosity and yield stress, and more importantly thixotropy and elasticity, can be interpreted in terms of a “site‐blocking” type flocculation.
Application of modified wastes from phenol‐formaldehyde resin and expanded polystyrene in sewage treatment processes
Authors: Bajdur Wioletta M. , Sułkowski Wiesław W. 
Published: October 2003

AbstractA solution to environmental pollution by polymer plastic wastes can be their chemical modification in to useful products. Such a new solution is the obtaining of effective flocculants for sewage treatment from chemically modified phenol‐formaldehyde resin production wastes (SE and NS novolak) and expanded polystyrene wastes. Comparative analysis of flocculation properties was performed for amino derivatives of novolak wastes, synthesized sulphonated derivatives of novolak and expanded polystyrene wastes, of standard polyacryloamide and for Praestol commercial polyelectrolyte. Amino derivatives and sulphonated derivatives of polymer plastic wastes, having properties of anionic type polyelectrolytes, exhibit good flocculation properties in purification processes of sewages with a chemical composition close to that of found in the water circulating system power plant, coal‐mine, and steel plant. Application of synthesised flocculants caused a decrease of turbidity, concentration of solved impurities and improved quality parameter of purified water. It was found that synthesised polyelectrolytes could be used in industrial water treatment processes.
On the convergence properties of the method of auxiliary sources in 2D problems with open boundaries
Authors: Papakanellos P. J. , Heretakis I. I. , Capsalis C. N. 
Published: October 2003

AbstractIn this paper, the convergence properties of the method of auxiliary sources (MAS) when applied to two‐dimensional (2D) problems with open boundaries are studied. Although such problems have been examined in the past, the relation of the solution errors with the sources' locations has not been reported in detail. Herein, the convergence behavior in the case of a single infinite wire above a flat ground is thoroughly examined. The dependence of the boundary‐condition errors on the number and spacing of the auxiliary sources is illustrated and general rules that govern their behavior are extracted. Finally, a few concluding remarks are outlined and their utilization for the advancement of the MAS is briefly discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 518–522, 2003
Fast and accurate modeling of finite‐thickness 2D‐EBG structures made by circular‐section rods
Authors: Frezza F. , Pajewski L. , Schettini G. 
Published: October 2003

AbstractIn this paper, electromagnetic crystals constituted by 2D arrays of dielectric rods with a circular cross section and rectangular‐lattice configuration are analyzed, and the transmission and reflection efficiencies are determined. The high convergence rate of the proposed technique is demonstrated. Results are presented for both TE and TM polarizations, showing the efficiencies as a function of physical and geometrical parameters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 433–437, 2003
A uniplanar wideband loop‐antenna design using an alternate inverted 2D cantor set sequence
Authors: Lee G. S. 
Published: October 2003

AbstractIn this paper a uniplanar wideband loop antenna is presented. The proposed antenna utilizes an inverted Cantor set matrix sequence of thinning and filling, taken by turns. With a 50Ω microstrip feed, an impedance bandwidth of 2–20 GHz (VSWR < 2.5) is obtained. The experimental results of return loss and radiation patterns are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 437–439, 2003
Novel input‐matching charts for microwave amplifier design
Authors: De Dominicis M. , Giannini F. , Limiti E. , Serino A. 
Published: October 2003

AbstractThe relationship between the amplifier input‐return loss (IRL) and the termination at the input of the active device is investigated and a useful expression relating the IRL to the available gain of the transistor is derived. Using such a relation, new charts for microwave amplifier design, which allow a direct tradeoff among often contrasting specifications, are generated. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 439–443, 2003
Modeling control over determination of dielectric properties by the perturbation technique
Authors: Komarov Vyacheslav V. , Yakovlev Vadim V. 
Published: October 2003

AbstractAn accompanying numerical simulation for obtaining field patterns, resonant frequencies, and the Q factor is proposed to evaluate the experimental conditions of complex permittivity reconstruction by the perturbation method and thereby improve its accuracy and flexibility. This approach is illustrated by analyzing the measurement of dielectric constant and the loss tangent of wet movie film in a rectangular resonator. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 443–446, 2003
Optically‐controlled solid‐state plasma leaky‐wave antenna
Authors: Grewal Gurvikram , Hanson George W. 
Published: October 2003

AbstractIn this paper, a 2D leaky‐wave antenna is designed for millimeter‐wave applications in the W band. We consider a method for scanning the antenna beam at a fixed frequency using optical control of the properties of a semiconductor waveguide. The analyses are done at 94 GHz using silicon, although other frequency ranges and materials are possible. Beam scanning is achieved by varying the density of an optically induced plasma, without otherwise modifying the antenna structure or changing the frequency. The steepest‐descent approximation is used to calculate the far‐field radiation pattern, where we show that the beam can be scanned over an approximately 30° range. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 450–453, 2003
A novel fractal defected ground structure and its application to the low‐pass filter
Authors: Liu Hai W. , Li Zheng F. , Sun Xiao W. 
Published: October 2003

AbstractA novel fractal defected ground structure (DGS) for the microstrip line is proposed. The DGS unit lattice is realized by replacing the etched rectangular holes in ground plane with a Sierpinski carpet. The proposed fractal DGS can provide better bandgap, slow‐wave characteristics, and selectivity at cutoff than the conventional dumbbell‐shaped DGS. Furthermore, the fractal DGS is applied effectively to design a low‐pass filter (LPF). A comparison between simulation and measurement confirms the validity of the LPF configuration and design procedure. A simple structure and high‐power handling capability are obtained from the proposed LPF. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 453–456, 2003
Efficient analysis of a class of microstrip antennas using the characteristic basis function method (CBFM)
Authors: Yeo Junho , Prakash V. V. S. , Mittra Raj 
Published: October 2003

AbstractThis paper presents a novel approach for the efficient solution of a class of microstrip antennas using the newly introduced characteristic basis functions (CBFs) in conjunction with the method of moments (MoM). The CBFs are special types of high‐level basis functions, defined over domains that encompass a relatively large number of conventional subdomain basis functions, for example, triangular patches or rooftops. The advantages of applying the CBF method (CBFM) are illustrated by several representative examples, and the accuracy as well as the computation time are compared to those of conventional direct computation. It is demonstrated that the use of CBFs can result in significant savings in computation time, with little or no compromise in the accuracy of the solution. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 456–464, 2003
Synthesis of patch antennas loaded by inhomogeneous substrates via a combined spectral domain: Genetic algorithm approach
Authors: Bilotti F. , Vegni L. , Urbani F. 
Published: October 2003

AbstractThe optimized design of patch antennas with inhomogeneous loading materials is presented in this paper. The analysis and a first coarse design of the antennas is applied to a numerical tool based on the method of moments (MoM) and on a full‐wave formulation developed in the spectral domain that exploits both rigorous and asymptotic closed‐form expressions of the Green's function for a stratified integrated structure with inhomogeneous substrates. In order to match the specific prescribed requirements for the antennas, then, the optimization of the patch shape (fine design) is performed by a dedicated subroutine implementing the genetic algorithm (GA) search and integrated in the aforementioned MoM numerical tool. Some numerical results showing the capabilities of the code are finally presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 464–468, 2003
A uniplanar picosecond impulse generator based on MESFET and SRD
Authors: Miao Meng , Nguyen Cam 
Published: October 2003

AbstractA new compact, low‐cost uniplanar impulse generator using coplanar waveguide structure has been designed, built, and tested. This uniplanar circuit consists of three functions: initial impulse generation, impulse amplification, and impulse compression, which are realized by a step‐recovery diode and two‐stage GaAs MESFET circuits, respectively. The impulse response has an amplitude of 2.3 V and a half‐power pulse width of 115 pS. It has larger amplitude and narrower pulse width than the impulse generated by the SRD circuit alone. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 470–472, 2003
A single‐port, dual‐frequency SSFIP antenna integrating a low‐pass filter
Authors: Zürcher J‐F. 
Published: October 2003

AbstractA new, very simple concept is proposed for realizing dual‐frequency antennas with arbitrary frequency separation. This idea is based on the SSFIP antenna principle and the use of a microstrip lowpass filter. It can be easily extended to any number of frequencies by simply adding antenna elements and low‐pass filters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 472–475, 2003
GaAs pHEMT broadband low‐noise amplifier for millimeter‐wave radiometer
Authors: Aja B. , de la Fuente M. L. , Pascual J. P. , Detratti M. , Artal E. 
Published: October 2003

AbstractThis paper describes a GaAs pHEMT low‐noise amplifier (LNA) in the 38–48 GHz frequency band, which has been developed for the radiometers of the ESA Planck mission. It demonstrates a stable LNA design using a potentially unstable device. The three‐stage amplifier with 0.15‐μm AlGaAs/InGaAs pHEMTs, exhibits more than 16‐dB gain and 1.8‐dB average noise figure over the entire frequency band. The minimum measured noise figure was 1.6 dB with an associated gain of 17.5 dB at 43 GHz. These results show the best noise performance demonstrated among all those reported for a broadband GaAs‐based LNA at these frequencies. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 475–479, 2003
A reliable architecture for FBG sensor systems
Authors: Peng Peng‐Chun , Chi Sien 
Published: October 2003

AbstractIn this paper, we present a reliable architecture for the fiber Bragg grating (FBG) sensor system. The architecture can perform a self‐healing function in the event of a fiber‐link failure. Such a self‐healing function is constructed by using a bidirectional ring topology with a linear‐cavity fiber‐laser source. The fiber laser adopted in this system can enhance the signal‐to‐noise ratio (SNR) of the entire sensing network up to 50 dB. The experimental results demonstrate the feasibility of our proposed architecture. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 479–482, 2003
Analysis of discontinuities in double‐negative (DNG) slab waveguides
Authors: Dong Hao , Wu Thomas X. 
Published: October 2003

AbstractIn this paper, we discuss new physical insights regarding the anomalous dispersion in the double‐negative (DNG) waveguide. Base on our analysis, the discontinuity structure of a grounded DNG slab waveguide, sandwiched between two dielectric slab waveguides, is investigated and the physical insights are also presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 483–488, 2003
Planar diversity‐loop antenna for wireless pcmcia card
Authors: Wong Kin‐Lu , Chen An‐Chia , Chang Fa‐Shian 
Published: October 2003

AbstractA diversity‐loop antenna mounted vertically on a wireless PCMCIA card for WLAN operation in the 5.2‐ and 5.8‐GHz bands is presented. The diversity‐loop antenna comprises two bent metal‐strip rectangular loop elements (each having a perimeter of about one wavelength of the center operating frequency) symmetrically mounted with respect to a rectangular ground plane protruding from the system ground plane of the PCMCIA card. In addition obtaining to a wide bandwidth covering the 5.2‐ and 5.8‐GHz bands, the diversity antenna shows good isolation of less than −27 dB for the two operating ports. In addition, the measured radiation patterns of the two bent‐loop elements in general cover complementary space regions, thus making this a promising antenna for providing spatial diversity in WLAN operation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 488–490, 2003
Microstrip coupled‐line bandpass filter with a multilayer structure
Authors: Chen Wu‐Nan , Weng Min‐Hung , Huang Tsung‐Hui , Cheng Tung‐Chieh , Dai Bun‐Tong 
Published: October 2003

AbstractA microstrip coupled‐line filter with a multilayer structure is designed and implemented. This structure provides additional overlapped coupling and cross coupling between two layers, except for the coupling effect on the same layer. The designed filter demonstrates the frequency characteristics with central frequency f0 = 2.4 GHz, return loss S11 = −12.2 dB, and insertion loss S21 = −2.49 dB. Moreover, it is found that, due to a transmission zero occurring at 3.14 GHz with −45‐dB rejection, a typical elliptic‐function response can be easily obtained by the proposed structure. Experimental results of the fabricated filter measured by using a network analyzer agree well with the simulation results. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 493–495, 2003
Broadband printed quasi‐self‐complementary antenna for 5.2/5.8 GHz WLAN operation
Authors: Wong Kin‐Lu , Wu Tzuenn‐Yih , Su Saou‐Wen , Lai Jeng‐Wen 
Published: October 2003

AbstractA broadband printed antenna with a quasi‐self‐complementary structure for WLAN operation in the 5.2‐ and 5.8‐GHz bands is presented. The antenna mainly comprises two radiating sections: a T‐shaped strip and a rectangular patch loaded with a T‐shaped slit. Both the T‐shaped strip and slit are of the same dimensions, thus the proposed antenna tends to be a self‐complementary structure. This antenna has a compact size of 6 × 21 mm2 and shows a wide bandwidth of about 1.5 GHz (about 4.6–6.1 GHz). Good antenna performance is obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 495–496, 2003
Installed performance of printed inverted‐F antennas (IFAs) at 2.45 GHz for bluetooth and 802.11b
Authors: Flint J. A. , Vardaxoglou J. C. 
Published: October 2003

AbstractDetuning is evaluated in the printed inverted‐F antenna for the 2.45‐GHz ISM band. Measurements and simulations are presented for a wooden desktop, a plastic enclosure, and an automobile body. Installed return loss differed significantly from free space and therefore near‐field and environmental‐resonance effects need to be accounted for. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 497–499, 2003
A photonics‐based wideband linearised mixer
Authors: Chan Erwin H. W. , Alameh Kamal E. , Minasian Robert A. 
Published: October 2003

AbstractA new wideband linearised photonic mixer structure based on a parallel topology of two electrooptic modulators is presented. This mixer realises a high spurious free‐dynamic range (SFDR), with additional advantages of requiring only a small amount of optical power and operating over a multioctave range. Experimental results for the linearised photonic mixer demonstrate a measured receiver‐noise limited SFDR of 115 dB · Hz4/5 with a low input optical‐power requirement of only 5 mW. This offers multi‐octave high dynamic range optical frequency conversion with wideband operation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 500–502, 2003