Distributed call rerouting in multiclass broadband networks

Broadband integrated services digital networks (B-ISDN) must handle multiclass traffic with diverse quality of service requirements. We consider a multiclass routing model in which routes are calculated in a distributed fashion by the call originating nodes. Within this general context, we address the problem of rerouting a set of previously routed calls to avoid a failed link. Under the approach we propose, a single node executes an aggregate, global rerouting of all affected calls and then converts the set of aggregate routes into an allocation of bandwidth on each link to call origination nodes for the purpose of rerouting. The bandwidth allocation is distributed to each origination node, which in turn then calculates routes for the individual calls. The problem faced by each call origination node is a variant of the socalled bandwidth packing problem. We develop and analyze an approximate algorithm for solving this problem in the specific context that arises in our setting.The research was supported by IBM Corporation and by NSF Grant No. CDR-8803012.On personal leave from IBM RTP.     

Effects of Ultrasonic Vibration on the Electroinitiated Copolymerisation of Styrene and Isoprene

Copolymerisation of styrene and isoprene by constant potential electrolysis in dichloromethane was achieved at different polymerisation potentials. Effect of ultrasonic vibration on the rate and the yield of polymerisation has been discussed. The composition of the copolymers was found to be affected by the vibration as well as the polymerisation potential (E_pol). At E_pol=+3.30 V we found that r₁=r₂ and mole percents of isoprene and styrene in copolymer were equal to each other. Equality was also observed on reacted monomer concentrations, at that potential, which can be called critical polymerisation potential. At E_pol values above or below the critical polymerisation potential none of the above-mentioned properties were equal. Monomer reactivity ratios were determined by the integrated Lewis-Mayo equation. Ultrasonic vibration as well as polymerisation potential was found to affect reactivity ratios.     

Reliability and validity of the Social Phobia and Anxiety Inventory for adolescents.

Although social anxiety is known to be common among adolescents, there are no self-report measures with demonstrated reliability and validity for this population. The Social Phobia and Anxiety Inventory (SPAI) is a measure of social anxiety developed for adults. The purpose of this study was to determine the reliability and validity of the SPAI for adolescents. The sample consisted of 223 adolescents (aged 12–18 yrs) from both clinical and community sources. Confirmatory factor analysis established the validity of the 2 separate factors of Social Phobia and Agoraphobia. Reliability estimates by Cronbach alpha were acceptable for the SPAI subscales and total. The SPAI demonstrated good construct validity, showing statistically significant relationships with independent measures of social phobia and other anxiety variables. The results demonstrate that the SPAI is a reliable and valid measure of social phobia for adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis, characterization and electrochromic properties of a conducting copolymer of pyrrole functionalized polystyrene with pyrrole

A well-defined polystyrene (PSt) based polymer containing at one end-chain 3,5-dibromobenzene moiety, prepared by atom transfer radical polymerization (ATRP), was modified in two reaction steps. First one constitutes a Suzuki coupling reaction between aromatic dibromine functional polymer and 3-aminophenylboronic acid, when a diamino-containing intermediate was obtained. The second step is a condensation reaction between the diamino functional polystyrene and 2-pyrrole aldehyde. Thus, a polymer containing a conjugated sequence having pyrollyl groups at the extremities was synthesized. The presence of oxidable pyrrole groups in the structure of the polymer permitted further electropolymerization. The structures of intermediate polymers were analyzed by spectral methods (¹H NMR, FTIR). Electrochemical copolymerization of pyrrole functionalized polymer (PStPy) with pyrrole was carried out in acetonitrile (ACN)-tetrabutylammonium tetrafluoroborate (TBAFB) solvent electrolyte couple. Characterization of the resulting copolymer were performed via Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), spectroelectrochemical analysis, and kinetic study. Spectroelectrochemical analysis show that the copolymer of PStPy with Py has an electronic band gap (due to π-π* transition) of 2.4 eV at 393 nm, with a yellow color in the fully reduced form and a blue color in the fully oxidized form. Via kinetic studies, the optical contrast %ΔT was found to be 20% for P(PStPy-co-Py). Results showed that the time required to reach 95% of the ultimate T was 1.7 s for the P(PStPy-co-Py).     

Electroinitiated and radiation-induced polymerisation of epoxycyclohexane

Liquid-state radiation-induced and electroinitiated polymerisations of epoxycyclohexane (ECH) have been investigated. The effect of temperature on the electroinitiated polymerisation rate was also studied. The decrease in monomer concentration during polymerisation was followed by gas chromatographic analysis of electrolysis solutions. The i.r. spectra of the polymers suggested polyether structure. N.m.r. spectra of products indicate that the polymerisation of ECH propagates through the opening of the epoxy rings. Poly(epoxycyclohexane) obtained by both methods are amorphous according to X-ray analyses.     

Electrochemical corrosion properties of metal alloys used in orthopaedic implants

This study concerns an investigation of the corrosion behavior of 316 stainless steel, CoCrMo and Ti6Al4V alloys in simulated body conditions (ringer lactate) at 37 °C by the use of Tafel plots, mixed potential and electrochemical impedance spectroscopy (EIS). Ti6Al4V alloy has the highest corrosion resistance followed by CoCr alloy. Ti6Al4V–CoCrMO was the best couple for galvanic corrosion with the minimum galvanic potential and current values according to mixed potential theory and Tafel method. It was concluded that Ti6Al4V was the most suitable material for implant applications in the human body.     

In vitro cytotoxicity of monticellite based bioactive ceramic powder synthesized from boron derivative waste

The cytotoxicity of monticellite based bioactive ceramic powder, which was synthesized from boron derivative waste has been determined by in vitro assays of MTT, NRU, and JC-1 staining. The toxicity of powder on different mammalian cell lines (3T3-L1, HUVEC, CRL-2120) was evaluated at the concentrations of 10, 100, 200, 400 and 800?µg/mL to justify its potential for biomedical applications. The obtained results showed that monticellite based bioactive ceramic powder possesses not only bioactive feature but also biocompatible characteristic at the concentration range of 10–200?µg/mL. Hence, monticellite based bioactive ceramics have high potential as a bone graft substitute for bone void filling and coating applications.     

Susceptor-assisted fast microwave sintering of TiN reinforced SiAlON composites in a single mode cavity

In the present study, 17 wt % TiN reinforced α-β SiAlON composites were sintered at low temperature by susceptor-assisted microwave heating. The effect of TiN addition on dielectrical properties of starting powders, as well as the influence of sintering temperature on phase evolution, microstructure development and mechanical properties of α/β-SiAlON-TiN composites were investigated. The obtained results showed that TiN addition increased the microwave absorbing properties which is reflected in the peak sintering temperature. Thus, the α:β ratio decreased and mechanical properties were improved, especially the fracture toughness of the composites. Furthermore, an estimate of energy consumption during microwave assisted sintering at the laboratory scale is presented. As a result, the highest values for relative density (97.1%), Vickers hardness (13.35 ± 0.47 GPa), and fracture toughness (7.52 ± 0.54 MPa m^1/2) were obtained by microwave sintering for 30 min at 1300 °C.     

Effect of layer thickness on the electrical parameters and conduction mechanisms of conjugated polymer‐based heterojunction diode

In this study, thickness‐dependent current density–voltage (J–V) characteristics obtained for poly{(9,9‐dioctylfluorene)?2,7‐diyl‐(4,7‐bis(thien‐2‐yl) 2‐dodecyl‐benzo[1,2,3] triazole)} (PFTBT) conjugated copolymer based heterojunction diode fabricated on ITO were investigated in terms of electrical characteristics. In order to analyze J –V plots with ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al configuration, the thickness‐dependent J–V measurements were applied in the thickness range between 90 and 200 nm. The effect of PFTBT:PC₆₁BM layer thickness on the forward J –V characteristics were investigated by evaluating electrical parameters such as zero bias barrier height (Φ_Bo), ideality factor (n ), shunt resistance (R _sh), series resistance (R_s ), the interface states density (N _ss), and space‐charge limited mobility. The results show that at PFTBT:PC₆₁BM layer thickness of 90 and 200 nm, ideality factor for ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al heterojunction diodes ranged from 2.726 to 3.121 and the thermionic emission over the heterojunction diodes is crucial at low current densities and the intrinsic thermally generated charge carriers controlled the forward current this region of the heterojunction diode. At relatively higher voltage, the current mechanism of ITO/PFTBT:PC₆₁BM/PEDOT:PSS/LiF/Al heterojunction diodes were found to obey a space charge limited (SCLC) conduction mechanism. The values of N_ss and R_s in heterojunction diodes increase with increasing PFTBT:PC₆₁BM layer thickness and effect the main electrical parameters of diodes. In addition, the leakage current of heterojunction diodes are taken and interpreted via Poole‐Frenkel emission and Schottky emission. The leakage current was controlled in ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al heterojunction diodes by Poole‐Frenkel emission above 140 nm and by Schottky emission under 140 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44817.     

AN INTERPRETATION OF THE IMPACT OF REGIONAL SCIENCE IN TERMS OF PHILOSOPHY OF SCIENCE

ABSTRACT: This article evaluates the performance of regional science from the perspective of the philosophy of science. The debate regarding the field's performance has drawn wide interest among those working in regional science and has been a stimulus to consider and reinterpret a number of approaches in the philosophy of science. It is believed that an evaluation and reinterpretation of the major approaches in the philosophy of science, such as the positivist, humanistic and structuralist outlooks, could be useful in helping make an ultimate evaluation of the recent literature regarding regional science. In this article, a comparison is made between those paradigms within the development processes that are relevant to regional science and with respect to differentiation between less developed countries (LDC) and developed countries. It is concluded that despite the considerable achievements that have occurred in regional science from the 1950s up to the present some significant questions in the field suggest requirements for a paradigm change, particularly for a field of knowledge that can be applied to developing areas.