bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling and Optimization of Nonlinear Polymerization Processes
Authors: Bachmann Rolf , Melchiors Martin , Avtomonov Evgeny 
Published: December 2016

SummaryReactions such as branching and crosslinking leading to nonlinear polymers play an important role in many polymerization productions, but they increase the sensitivity of the processes and increase the requirements for their design and control. It is therefore desirable to have an accurate and simple means to model these processes. However, the simplest method for the description of the polymers: the method of moments was said to fail in the nonlinear case because of the so called closure problem. It will be shown here how to extend the method of moments to nonlinear processes in the pregel region − except scission − and thus provide a simple means for the simulation and optimization of the main parameters of a polymer distribution. Furthermore, the assumption of one radical per polymer molecule is no longer needed. The formulas allow average polymer properties to be easily included in flow sheet simulations or computational fluid dynamics codes and allow checking other more elaborate codes for the description of polymer distributions. Examples will be given for free radical polymerizations. An approximation in case of scission will be discussed together with an application to reversible polycondensation.
A Simplified Model to Describe the Effect of Alkyl Anilines on the Polymerization of Methyl Methacrylate
Authors: Moreno Valeria Casson , Rubinato Alberto , Maschio Giuseppe 
Published: December 2016

SummaryIn the formulation of acrylic coatings, monomer blends are required to cure in situ using a peroxide initiator. Curing accelerators (typically alkyl anilines) are added to the blend in order to initiate the curing process at room temperature. This was proved to cause a process safety issue related to the presence of accelerators that increase the possibility of runaway reactions especially at industrial scale. In this paper, the polymerization of methyl methacrylate containing different curing accelerators has been studied. Based on Differential Scanning Calorimetry tests, a simplified kinetic model for the polymerization process has been developed, describing the induction time due to the presence of stabilizers, the global kinetic rate, and the influence of diffusion phenomena, based on a free volume theory approach specifically modified for the free radical polymerization of methyl methacrylate added with different types of accelerators.
Extensible compact 8‐port MIMO antenna with pattern gain
Authors: Lee D.‐J. , Lee S.‐J. , Khang S.‐T. , Yu J.‐W. 
Published: December 2016

ABSTRACTA novel and compact 8‐port multi‐input multioutput (MIMO) antenna is presented, which uses pattern gain to achieve more than an ideal 6‐port polarimetric antenna gain. Antenna elements types, geometry on the common ground and antenna elements rotation are optimized for the pattern gain. The antenna consists of four pairs of inverted‐F antennas, quarter wavelength slot antennas, parasitic elements, and ground plane. For the orthogonality, the inverted‐F antenna for electric dipole and slot antenna for magnetic dipole are selected as elements of radiator. Four pairs of the inverted‐F antenna and slot antenna symmetrically stand on the ground and the antenna direction, location and the parasitic elements are studied for low mutual coupling and correlation. The proposed MIMO antenna shows isolation of better than −10 dB with an overall size of 0.5λ × 0.5λ × 0.13λ. The ergodic capacity of proposed antenna is presented to verify the MIMO antenna performance. The proposed 8‐port MIMO antenna is extensible to 40‐port antenna cube and its prototype is presented. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:236–240, 2017
A compact multidirectional UWB MIMO slot antenna with high isolation
Authors: Srivastava Gunjan , Mohan Akhilesh , Chakraborty Ajay 
Published: December 2016

ABSTRACTA compact multiple‐input‐multiple‐output (MIMO) antenna with high inter‐element isolation without any decoupling network for UWB applications is proposed in this communication. Each antenna element is realized by etching the stepped slots in the ground plane. The stepped slot antenna not only reduces the footprint of the proposed antenna, but also provides directional radiation behavior which leads to high isolation among them. Each of the antenna element is radiating in one of the four cardinal directions, that results in multidirectional radiation characteristics. The prototype of the proposed antenna is fabricated and measured. The size of the compact UWB MIMO antenna is 24 × 24 × 0.8mm3. The designed antenna radiates (S11 ≤ −10 dB) in the frequency spectrum of 3 GHz–10.9 GHz, with inter‐element isolation better than 20 dB. The acceptable values of envelope correlation coefficient (ECC) and channel capacity loss (CCL) guarantees good MIMO performance. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:243–248, 2017
FMCW transceiver of short‐range proximity sensor in sea clutter
Authors: Choi J. H. , Lee J. M. , Jung M. S. , An J. Y. , Kim K.L. 
Published: December 2016

ABSTRACTA frequency‐modulated continuous‐wave (FMCW) transceiver of short‐range proximity sensor in sea clutter is presented. A higher rejection of sea clutter is achieved by employing an FMCW modulation. The FMCW transceiver has wide bandwidth, low phase noise, super linearity to detect a target in short‐range (some meters) against sea clutter having a radar cross section (RCS) relatively larger than that of the target. The performances of the proximity sensor are experimentally verified by an indoor test in a simulated sea clutter environment. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:334–337, 2017
Analysis and design of a broadband coplanar Wilkinson power divider at X‐band
Authors: Han Juzheng , Liao Xiaoping 
Published: December 2016

ABSTRACTThe analysis and design methods of a broadband coplanar Wilkinson power divider are proposed in this paper. The novelty is that cascaded two sections of coupled asymmetrical coplanar strips (ACPSs) are utilized to obtain broadband performance over X‐band and two resistors are used for isolation. The design equations are derived using even‐ and odd‐mode analysis. The specific structure parameters for broadband performance over X‐band are obtained through electronic design simulation tool and quasi‐static conformal mapping technique. The power divider is fabricated on GaAs substrate and is compatible with GaAs MMIC process. The measured results of the power divider show close agreement with the simulation. The measured return loss S11 is better than −15 dB across the entire X‐band, 8–12 GHz. Good dividing and high isolation properties are also revealed through measurements. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:307–312, 2017
A high directive Koch fractal Vivaldi antenna design for medical near‐field microwave imaging applications
Authors: de Oliveira Alexandre M. , Justo João F. , Perotoni Marcelo B. , Kofuji Sérgio T. , Neto Alfredo G. , Bueno Regis C. , Baudrand Henri 
Published: December 2016

ABSTRACTWe present a new fractal slot edge antipodal Vivaldi antenna (AVA). When compared to a conventional AVA, it simultaneously extends the low‐end bandwidth limitation, mitigates the side lobe level, and increases the main lobe gain. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:337–346, 2017
A printed quasi‐Yagi antenna with dual‐stub‐loaded parasitic strip director for bandwidth enhancement
Authors: Xu Kai‐Da , Xu Han , Liu Yan‐Hui , Liu Qing‐Huo , Zeng Qingsheng 
Published: December 2016

ABSTRACTA novel printed quasi‐Yagi antenna with dual stubs loaded on a parasitic strip director has been presented. The impedance bandwidth is analyzed and compared when we add or eliminate the parasitic strip director. Then, two open stubs are loaded on the strip to excite an additional resonant mode, which lead to a wider impedance bandwidth. To demonstrate the effectiveness of this design, an antenna prototype is fabricated and tested. Experimental results show that the antenna provides a bandwidth ranging from 4.4 to 9.3 GHz and within the whole band larger than 4.1 dBi gain is achieved. Additionally, the proposed antenna presents a stable end‐fire radiation directivity and low cross‐polarization level at different frequencies with a compact structural size of 35 mm × 26 mm. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:447–451, 2017
Electronically reconfigurable filtenna for cognitive radios
Authors: Nachouane Hamza , Najid Abdellah , Riouch Fatima , Tribak Abdelwahed 
Published: December 2016

ABSTRACTA frequency tunable and bandwidth reconfigurable antenna with ring slot resonators embedded into its ground plane is presented. To achieve the bandwidth reconfigurability, two PIN diodes are inserted to couple or decouple two pairs of ring slot resonators from the antenna feed line. By switching the diodes on or off, the antenna can operate either in a wideband or narrowband mode. In the narrowband mode, two varactors are used to continuously tune the antenna operating frequency from 2.55 to 3.2 GHz. Due to the achieved bandwidths, the proposed structure can cover various bands used for LTE (1/2/7/33‐41 bands), WiMAX, and WLAN (802.11 b/g/n/s bands) applications. Similar radiation patterns with low cross‐polarization levels are obtained for different diodes states. The measured results show that the proposed design is potentially suitable for cognitive radio applications; in which the wideband mode is used for spectrum sensing while the narrowband mode for communicating over the selected channels. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:399–404, 2017
Enhanced window breakdown threshold of the split‐horn antenna using an E‐plane field shaper
Authors: Choi Jun‐Ho , Shin Jin‐Woo , So Joon‐Ho 
Published: December 2016

ABSTRACTA compact split‐horn antenna with a high‐power handling capability to be able to radiate high‐power pulse energy through vacuum dielectric window into the free space without the occurrence of dielectric/air breakdown is proposed at S‐band. To increase the threshold of dielectric/air and vacuum/dielectric breakdown, it uses the special E‐plane field shaper at the edges of the split‐horn aperture. The proposed split‐horn antenna has a high‐power handling capability of 50 MW which is five times larger than that of the conventional split‐horn antenna of 10 MW for the air breakdown threshold of 30 kV cm−1 as well as a similar antenna gain and a radiation pattern. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:442–447, 2017
An 8.5 GHz, 0.4 V, 300 ΜW armstrong VCO with dual transformer feedback and capacitor‐splitting gate inductive feedback
Authors: Gul Muhammad Talha , Ngo Duc Viet , Nguyen Xuan Tien , Lee Jong‐Wook , Park Hun‐Kuk 
Published: December 2016

ABSTRACTWe present a low‐voltage Armstrong voltage‐controlled oscillator (VCO) suitable for an efficient low‐power wireless connectivity solution. The VCO employing dual transformer feedback in the Armstrong structure is further augmented with low‐power design techniques: the use of a cross‐coupled differential pair, dual transconductance boosting, and capacitor‐splitting gate inductive feedback. The dual transformer feedback and dual transconductance boosting effectively increase the output swing. In addition, the cross‐coupled differential pair is combined with capacitor‐splitting gate inductive feedback, which further reduces the transconductance for startup. The proposed VCO has been fabricated in a 0.18 μm CMOS process; the fabricated device showed successful oscillation at 8.5 GHz while consuming 300 μW at 0.4 V, and its measured phase noise was −104.3 dBc/Hz at a 1‐MHz frequency offset. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:384–388, 2017
A high power fully integrated single‐chip CMOS transmitter for wireless communication of unmanned aircraft system
Authors: Roy Palash , Dawn Debasis 
Published: December 2016

ABSTRACTThis letter presents a high power fully integrated single‐chip CMOS transmitter for automatic dependent surveillance‐broadcast (ADS‐B) of unmanned aircraft system (UAS), operating at both 978 MHz Universal Access Transceiver (UAT) mode and 1090 MHz Extended Squitter (1090 ES) mode. The 4.38 mm × 0.95 mm fully‐integrated transmitter chip fabricated using 0.18 um CMOS process exhibits modulated output power of 23 dBm at 978 MHz with 102 MHz bandwidth, showing a potential replacement of the state‐of‐the‐art technology by significantly reducing the size and overall cost of the complete ADS‐B system. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:432–439, 2017
High‐gain wide‐bandwidth low noise amplifier multi‐chip waveguide module at V‐band
Authors: Tolani Harshita , Rao Ch. V. N. 
Published: December 2016

ABSTRACTA low‐noise, high‐gain, wide‐bandwidth multi‐chip module has been developed at V‐Band with WR‐15 waveguide interface using commercial‐off‐the‐shelf (COTS) Low Noise Amplifier (LNA) Monolithic Millimeter‐wave Integrated Circuits (MMICs). Waveguide module design ensures there is minimal impact on noise figure and gain of MMICs due to integration on the module and it is rugged to sustain impact of fabrication/assembly tolerances. The realized six‐stage LNA module has small‐signal gain of 32–35 dB and room temperature noise figure ranging from 2.2 to 4.4 dB in 50–60 GHz frequency band. The module design has been simulated using 3D electromagnetic solver ‐ High Frequency Structure Simulator (HFSS). © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:380–384, 2017
Dielectric analysis of liquid solvents using microwave resonator sensor for high efficiency measurement
Authors: Mohd Bahar Amyrul Azuan , Zakaria Z. , Ab Rashid S. R. , Isa A. A. M. , Alahnomi Rammah A. 
Published: December 2016

ABSTRACTA microwave ring resonator sensor has been practically applied as a micro‐volume sensor dedicated to solvent characterization with perspectives for chemical substances. The tested microliter range liquid solution is placed on capillary glass which is a compatible medium for planar sensor integration. The electrical response between electric field and solvent is converted into a predictable relationship between dielectric properties and the relative permittivity of the solution. A compact split ring resonator has been fabricated and tested with several common solvents on trace amount of volume. The result achieved recorded a very high Q factor of 525 making it practically suitable for beverages industry application. Good agreement has been achieved between the theoretical, simulation, and parameters measurement where the measurement errors of the complex permittivity is less than 0.5%, validating the concept of the accurate characterization theory using planar sensor. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:367–371, 2017
Compact ultra‐wideband fractal monopole antenna with high gain using single layer superstrate
Authors: Singha Rahul , Vakula D. 
Published: December 2016

ABSTRACTA novel technique is applied on fractal monopole antenna to enhance gain for ultra wideband (UWB) applications. The fringing field effect of the antenna is increased by using dielectric superstrate, and it is designed by fabricating rectangular conductor on single side of the superstrate with dimension 10 × 21.5 mm2. The fractal structure is designed by the identical triangle structure in the radiating patch. The dielectric superstrate is placed on the fractal monopole antenna. At the time of feeding, the conductor of the superstrate is connected through ground plane of the antenna. The overall dimension of the fractal monopole antenna with superstrate is 24.5 × 21.6 × 3.15 mm3. The measurement result of the reflection coefficient is below −10 dB indicating impedance bandwidth of 3.1 to 11 GHz. The measured radiation patterns are also improved and peak gain of the conventional antenna increases approximately 1.6 dB by using superstrate with reference to conventional design. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:482–488, 2017
Low profile UHF loop antenna prototyped and investigated by circuit modeling
Authors: Taghvaee H. , Habibi A. , Rezaee A. , Zarinkhat F. 
Published: December 2016

ABSTRACTHere we proposed a low profile antenna which is an electrically coupled loop fed by a coaxial cable and operates in UHF band. With acquisition of a square loop, near zone is covered by magnetic field that has no harm to living being. By optimizing the dimensions with genetic algorithm 12% of bandwidth, 2.45 dB realized gain and 33% miniaturization (
) at 500 MHz is obtained. Afterwards, the performance of the antenna is analyzed with a general circuit model and verified using frequency domain solver simulation. In the measurement phase a technique was discovered improving the bandwidth even more, hence 150 MHz bandwidth equal 30% at 500 MHz was achieved. These characteristics together make this antenna very beneficial in mobile terminals that have a very wide area of applications such as ground station targeting UAVs and where antennas need to operate close to the human body. Due to semidirectional radiation pattern it can be used in short and medium range remote wireless bridge networks. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:459–463, 2017
The thoracic outlet syndromes: Part 2. The arterial, venous, neurovascular, and disputed thoracic outlet syndromes
Authors: Ferrante Mark A. , Ferrante Nicole D. 
Published: December 2016

ABSTRACTThe thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOSs as cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and electrodiagnostic manifestations of these pathophysiologies is required. This review of the TOSs is provided in 2 parts. In part 1 we covered general information pertinent to all 5 TOSs and reviewed true neurogenic TOS in detail. In part 2, we review the arterial, venous, traumatic neurovascular, and disputed forms of TOS. Muscle Nerve 56: 663–673, 2017
The thoracic outlet syndromes: Part 1. Overview of the thoracic outlet syndromes and review of true neurogenic thoracic outlet syndrome
Authors: Ferrante Mark A. , Ferrante Nicole D. 
Published: December 2016

ABSTRACTThe thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOS as a cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and the electrodiagnostic manifestations of their pathophysiologies is required. This review of the TOSs is provided in 2 parts. In this first part we address information pertinent to all 5 TOSs and reviews true neurogenic TOS. In part 2 we review the other 4 TOSs. Muscle Nerve 55: 782–793, 2017
The additional effects of a probiotic mix on abdominal adiposity and antioxidant Status: A double‐blind, randomized trial
Authors: Gomes Aline Corado , de Sousa Rávila Graziany Machado , Botelho Patrícia Borges , Gomes Tatyanne Letícia Nogueira , Prada Patrícia Oliveira , Mota João Felipe 
Published: December 2016

ObjectiveTo investigate whether a probiotic mix has additional effects when compared with an isolated dietary intervention on the body composition, lipid profile, endotoxemia, inflammation, and antioxidant profile.MethodsWomen who had excess weight or obesity were recruited to a randomized, double‐blind trial and received a probiotic mix (Lactobacillus acidophilus and casei; Lactococcus lactis; Bifidobacterium bifidum and lactis; 2 × 1010 colony‐forming units/day) (n = 21) or placebo (n = 22) for 8 weeks. Both groups received a dietary prescription. Body composition was assessed by anthropometry and dual‐energy X‐ray absorptiometry. The lipid profile, lipid accumulation product, plasma fatty acids, lipopolysaccharide, interleukin‐6, interleukin‐10, tumor necrosis factor‐α, adiponectin, and the antioxidant enzymes activities were analyzed.ResultsIn comparison with the dietary intervention group, the dietary intervention + probiotic mix group showed a greater reduction in the waist circumference (−3.40% vs. −5.48%, P = 0.03), waist‐height ratio (−3.27% vs. −5.00%, P = 0.02), conicity index (−2.43% vs. −4.09% P = 0.03), and plasma polyunsaturated fatty acids (5.65% vs. −18.63%, P = 0.04) and an increase in the activity of glutathione peroxidase (−16.67% vs. 15.62%, P < 0.01).ConclusionsSupplementation of a probiotic mix reduced abdominal adiposity and increased antioxidant enzyme activity in a more effective way than an isolated dietary intervention.
Understanding the Effects of Roasting on Antioxidant Components of Coffee Brews by Coupling On‐line ABTS Assay to High Performance Size Exclusion Chromatography
Authors: Opitz Sebastian E.W. , Goodman Bernard A. , Keller Marco , Smrke Samo , Wellinger Marco , Schenker Stefan , Yeretzian Chahan 
Published: December 2016

AbstractIntroductionCoffee is a widely consumed beverage containing antioxidant active compounds. During roasting the phytochemical composition of the coffee bean changes dramatically and highly polymeric substances are produced. Besides chlorogenic acids that are already present in green coffee beans, melanoidins show antioxidant capacity as well.ObjectiveTo employ post‐column derivatisation by coupling high performance size exclusion chromatography (HPSEC) to an antioxidant assay to investigate the effect of roasting on the properties of antioxidant active compounds in coffee brews.MethodologyWe have investigated the antioxidant capacity of Coffea arabica (Arabica) and C. canephora (Robusta) beans that were roasted over the full spectrum of roast conditions (four roasting speeds to three roast degrees) by comparing the results from HPSEC coupled on‐line to the ABTS assay with those from two batch assays, Folin Ciocalteu (FC) and oxygen radical absorbance capacity (ORAC) assay.ResultsThe antioxidant capacity showed a general decrease towards slower and darker roasted coffee for all three assays, indicative of heat degradation of active compounds. Hence, low molecular weight (LMW) compounds such as chlorogenic acids (CGAs) decreased progressively already from relatively mild roasting conditions. In contrast, high molecular weight (HMW) compounds (e.g. melanoidins) increased from light to dark roast degrees with lowering magnitude towards slower roasting profiles.ConclusionBy coupling HPSEC on‐line to the ABTS assay we were able to separately quantify the contribution of HMW and LMW compounds to the total antioxidant capacity, increasing our understanding of the roast process. © 2016 The Authors. Phytochemical Analysis Published by John Wiley & Sons Ltd.