scholarly journals Effects of the fabric substrate on performance and durability of textile-embroidered dipole antennas

2021 ◽  
pp. 004051752110149
Author(s):  
Heura Ventura ◽  
Ferran Parés ◽  
Raul Fernández-García ◽  
Ignacio Gil ◽  
Monica Ardanuy
Keyword(s):  
Resonance Frequency ◽  
Return Loss ◽  
Woven Fabrics ◽  
Elastic Fibers ◽  
Dipole Antennas ◽  
Washing Fastness ◽  
Lower Stability ◽  
Composition And Structure ◽  
Before And After

In this work, several fabrics with different composition and structure have been used as the substrate for the production of wearable textile-embroidered dipole antennas. The performance of the antennas has been determined by measuring their resonance frequency, return loss and bandwidth. To determine their durability as wearable fabrics, the performance has been assessed before and after subjecting the antennas to washing and abrasion cycles. The results revealed that the woven fabrics presented a good washing fastness, even in fabrics having elastic fibers or low-crimp structures. In all cases, a good performance of the antennas was maintained after 30 washing cycles. For the abrasion cycles, the substrates with higher stability (measured as the crimp ratio) presented a higher wear fastness, whereas a higher variability was observed for the substrates with lower stability.

scholarly journals Gut Microbiome in a Russian Cohort of Pre- and Post-Cholecystectomy Female Patients

2021 ◽  
Vol 11 (4) ◽  
pp. 294
Author(s):  
Irina Grigor’eva ◽  
Tatiana Romanova ◽  
Natalia Naumova ◽  
Tatiana Alikina ◽  
Alexey Kuznetsov ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Relative Abundance ◽  
Gut Microbiome ◽  
Gallstone Disease ◽  
Illumina Miseq ◽  
Rrna Gene ◽  
Bacterial Phyla ◽  
Female Patients ◽  
Composition And Structure ◽  
Before And After

The last decade saw extensive studies of the human gut microbiome and its relationship to specific diseases, including gallstone disease (GSD). The information about the gut microbiome in GSD-afflicted Russian patients is scarce, despite the increasing GSD incidence worldwide. Although the gut microbiota was described in some GSD cohorts, little is known regarding the gut microbiome before and after cholecystectomy (CCE). By using Illumina MiSeq sequencing of 16S rRNA gene amplicons, we inventoried the fecal bacteriobiome composition and structure in GSD-afflicted females, seeking to reveal associations with age, BMI and some blood biochemistry. Overall, 11 bacterial phyla were identified, containing 916 operational taxonomic units (OTUs). The fecal bacteriobiome was dominated by Firmicutes (66% relative abundance), followed by Bacteroidetes (19%), Actinobacteria (8%) and Proteobacteria (4%) phyla. Most (97%) of the OTUs were minor or rare species with ≤1% relative abundance. Prevotella and Enterocossus were linked to blood bilirubin. Some taxa had differential pre- and post-CCE abundance, despite the very short time (1–3 days) elapsed after CCE. The detailed description of the bacteriobiome in pre-CCE female patients suggests bacterial foci for further research to elucidate the gut microbiota and GSD relationship and has potentially important biological and medical implications regarding gut bacteria involvement in the increased GSD incidence rate in females.

scholarly journals Investigation of the Tribological Performances of Graphene and WS2 Nanosheets as Additives for Perfluoroalkylpolyethers Under Simulated Space Environment

2021 ◽  
Vol 69 (2) ◽  
Author(s):  
Jia Ren ◽  
Kuiliang Gong ◽  
Gaiqing Zhao ◽  
Wenjing Lou ◽  
Xinhu Wu ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Atomic Oxygen ◽  
Friction And Wear ◽  
Surface Oxidation ◽  
Space Environment ◽  
Composition And Structure ◽  
Before And After ◽  
Wear Reduction ◽  
Ws2 Nanosheets ◽  
Effects Of Irradiation On

AbstractThe tribological performances of perfluoroalkylpolyethers (PFPE) with graphene (Gr), WS2, and the mixture of Gr and WS2 (Gr + WS2) before and after ultraviolet (UV), atomic oxygen (AO), and proton (Pr) irradiations were investigated. The composition and structure of PFPE, Gr, WS2, and Gr + WS2 were also analyzed to understand the effects of irradiation on the tribological behaviors of PFPE with additives. The results indicated that serious deterioration and degradation of PFPE took place and Gr was transformed to amorphous carbon after Pr irradiation, and surface oxidation of WS2 occurred under the irradiations of AO and Pr. Moreover, compared to PFPE and PFPE additized with Gr and WS2, PFPE with the addition of Gr + WS2 exhibited excellent friction and wear reduction before and after UV and AO irradiations. Graphical Abstract

scholarly journals Design of PCB Impedance Matching Inductors and Antennas for Single-Chip Communication Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
J. Chung ◽  
S. Hamedi-Hagh
Keyword(s):  
Dielectric Constant ◽  
Resonance Frequency ◽  
Communication Systems ◽  
Return Loss ◽  
Impedance Matching ◽  
Portable Device ◽  
Single Chip ◽  
Matching Network

This paper presents the design of an inductor and an antenna for a portable device with GPS and FM capabilities. The inductor is designed to operate at the lower frequency FM band as part of a matching network and the antenna is designed to operate at the higher frequency GPS L1 band. The FR4 PCB used has a thickness of 1.6 mm with a dielectric constant of 3.8 and has two metallization layers. The inductor is designed with 1.5 mm trace width, 3.5 turns, and has a dimension of 14.5 mm × 14.5 mm. It has an inductance of 95 nH, a resistance of 2.9 Ω, a self-resonance frequency of 500 MHz, and a maximum Q of 51 from 100 MHz to 200 MHz (FM band). The antenna has a dimension of 49 mm × 36 mm and is designed to operate at 1.5754 GHz L1 band. It also has a return loss of −36 dB and a measured bandwidth of 250 MHz.

scholarly journals Application of Natural Dyes and Sodium Alginate From Sargassum Sp. Sea weed In Coloring Bima Woven Fabric

2020 ◽  
Vol 36 (05) ◽  
pp. 964-967
Author(s):  
Agrippina Wiraningtyan ◽  
Ruslan Ruslan ◽  
Putri Ayu Mutmainnah ◽  
Magfirah Perkasa
Keyword(s):  
Surface Structure ◽  
Sodium Alginate ◽  
Morphological Analysis ◽  
Woven Fabrics ◽  
Natural Dyes ◽  
Woven Fabric ◽  
Dyeing Process ◽  
Wave Numbers ◽  
Absorption Pattern ◽  
Before And After

This study aims to extract dye and alginate from seaweed Sargassum sp. as a dye paste in the coloring of Bima woven fabric. The concentration of sodium alginate used was 0%; 1%; 3% and 5%. The results showed that the absorbance value of the dye extract from seaweed Sargassum sp at maximum λ = 203 nm obtained A = 3.899. The effect of variations in the concentration of sodium alginate in the dye paste was determined by comparing the FTIR absorption pattern of Bima woven fabrics. Based on the FTIR absorption pattern data, it was found that a mixture of dye and sodium alginate of 3% had a stronger intensity, namely the wave numbers 3448.72 cm-1 and 1635 cm-1; 2900.94 cm-1; 2337.72 cm-1; 1381.03 cm-1 and 1064.71 cm-1. The results of the morphological analysis showed significant differences in surface structure on Bima woven fabrics before and after the dyeing process.

scholarly journals Investigation of Observed Changes in Treated Hemp Hurds

2016 ◽  
Vol 62 (3) ◽  
pp. 22-26 ◽  
Author(s):  
Ivana Schwarzová
Keyword(s):  
Current Trend ◽  
Renewable Materials ◽  
Physico Chemical ◽  
Composition And Structure ◽  
Characterization Study ◽  
Hemp Fibres ◽  
Before And After ◽  
Industrial Hemp ◽  
Morphology Characterization ◽  
Inorganic Matrix

Abstract The effort to achieve sustainable development using renewable materials instead of limited ones is the current trend in the construction industry. Need for the development of environmentally friendly products is related to industrial interest in using natural plant fibres as reinforcement in composites. The combination of organic filler and inorganic matrix creates high-quality products such as fibre boards and composites. Industrial hemp fibres are one of the mostly used natural fibres and due to their unique mechanical, thermal insulation, acoustic and antiseptic properties have a great potential in composite materials. However, improving the interfacial bond between fibre and matrix is an important factor in fibre-reinforced composites. Optimizing the adhesion between fibre and inorganic matrix is related to surface treatment processes. This paper deals with morphology characterization, study changes in the chemical composition and structure of hemp fibres using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) before and after physico-chemical treatment.

scholarly journals Preparation of Silver-Plated Para-Aramid Fiber by Employing Low-Temperature Oxygen Plasma Treatment and Dopamine Functionalization

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 599 ◽  
Author(s):  
Zhenhua Sun ◽  
Yanfen Zhou ◽  
Wenyue Li ◽  
Shaojuan Chen ◽  
Shihua You ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Silver Nanoparticles ◽  
Plasma Treatment ◽  
Electrical Resistance ◽  
Oxygen Plasma ◽  
Attenuated Total Reflection ◽  
Oxygen Plasma Treatment ◽  
Washing Fastness ◽  
Before And After ◽  
Electroless Silver Plating

Direct electroless silver plating of para-aramid (PPTA) is difficult due to its extremely low surface chemical energy. In order to facilitate the deposition of silver nanoparticles and to enhance the washing fastness, oxygen plasma treatment and dopamine modification were conducted before silver plating of PPTA fibers. Various techniques including scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffractometer (XRD) and thermogravimetric analyzer (TGA) were used to characterize the surface morphology, chemical composition and thermal stability of the silver-plated PPTA fibers. Electrical resistance and silver content of the silver-coated PPTA fibers before and after standard washing were also studied. The results showed that silver nanoparticles were successfully coated onto the surface of PPTA fibers with and without plasma treatment, but the coating continuity and the electrical conductivity of the silver-coated PPTA fibers were greatly enhanced with the assistance of plasma treatment. It was also demonstrated that the washing fastness of silver-coated PPTA fibers was improved after plasma treatment as indicated by electrical resistance and continuity of the silver nanoparticles after various washing cycles. It was found that the electrical resistance of plasma-treated PPTA-PDA/Ag fibers prepared at an AgNO3 concentration of 20 g/L reached 0.89 Ω/cm and increased slightly to 0.94 Ω/cm after 10 standard washing cycles. The silver-coated PPTA fibers also showed stable electrical conductivity under 250 repeated stretching-releasing cycles at a strain of 3%.

Fabrication of Porous n-HA/PA66 Composite for Bone Repair

2007 ◽  
Vol 330-332 ◽  
pp. 321-324 ◽  
Author(s):  
Hong Li ◽  
Yu Bao Li ◽  
Yong Gang Yan ◽  
Ji Dong Li ◽  
Ai Ping Yang ◽  
...  
Keyword(s):  
Bone Repair ◽  
Average Diameter ◽  
Processing Parameters ◽  
Pressing Method ◽  
Composition And Structure ◽  
Porous Architecture ◽  
Before And After ◽  
The Matrix ◽  
Thermal Pressing ◽  
Defect Repair

Using nano-hydroxyapatite/polyamide66 composite (n-HA/PA66) and a special foamer as start materials, a porous species for bone defect repair was successfully developed by thermal-pressing method. The resulting material presented: (1) high compressive strength which reached 13~46MPa; (2) excellent porous structure, the average diameter of pores in the matrix was in range of 280μm to 500μm and porosity of 36% to 57%. The porous architecture could be adjusted by the combination of processing parameters such as the weight of start mixture used per mold and the ratio of composite to foamer as well as n-HA content in the composite. No apparent change in composition and structure of n-HA/PA66 composite was found by XRD and IR determination before and after formation of porous species. According to Sherrer equation, the value of D(002) of n-HA crystals in porous material and start powder were about 70nm, indicating no occurrence of change in size of n-HA during the thermal-pressing procedure. Additionally, no foamer residual was detected in porous species.

Thermal resistance of polyurethane-coated knitted fabrics before and after weathering

2014 ◽  
Vol 84 (19) ◽  
pp. 2015-2025 ◽  
Author(s):  
Vesna Marija Potočić Matković ◽  
Ivana Salopek Čubrić ◽  
Zenun Skenderi
Keyword(s):  
Thermal Resistance ◽  
Thermal Protection ◽  
Winter Season ◽  
Outdoor Exposure ◽  
Woven Fabrics ◽  
Knitted Fabric ◽  
Knitted Fabrics ◽  
Coated Fabric ◽  
Before And After ◽  
Coated Fabrics

Polyurethane-coated knitted fabrics are of interest because they exhibit several positive properties, they are more stretchable, elastic and comfortable than coated woven fabrics and yet they are little studied. Information of weather durability, as well as thermal properties, is essential to ensure thermal protection for textile materials intended for outdoor use. In the presented research, a series of coated knitted fabrics for protective clothing were developed and exposed to weathering in summer and winter seasons. After three months of outdoor exposure, thermal resistance of all the tested materials decreased by 13% after the summer season and 25% after the winter season. A very good correlation of knitted fabric mass per unit area and thermal resistance of knitted fabric, coated fabric and aged coated fabric occurred. The studied materials experienced a partial degradation of the polyurethane layer, which is not related to the deterioration of the knitted substrate. The presented investigation of thermal resistance of coated fabrics and their dependence on the knitted substrate, as well as the influence of environmental conditions, allows the improvement of coated fabrics with the aim of better thermal protection.

The Researches on Upgrading of Heavy Crude Oil by Catalytic Aquathermolysis Treatment Using a New Oil-Soluble Catalyst

2012 ◽  
Vol 608-609 ◽  
pp. 1428-1432 ◽  
Author(s):  
Wen Long Qin ◽  
Zeng Li Xiao
Keyword(s):  
Heavy Oil ◽  
Saturated Hydrocarbon ◽  
New Technology ◽  
Viscosity Reduction ◽  
Catalytic Aquathermolysis ◽  
Composition And Structure ◽  
Before And After ◽  
Heavy Crude

The aquathermolysis of Shengli heavy oil during steam stimulation was studied by using a new oil-soluble catalyst for the reaction in this paper. The laboratory experiment shows that the viscosity reduction ratio of heavy oil is over 75% at the circumstances of 200°C, 24 hs, 0.3 % catalyst solution. The viscosity of upgraded heavy oil is changed from 25306mPa•s to 6175mPa•s at 50°C. The chemical and physical properties of heavy oil both before and after reaction were studied by using column chromatography (CC) analysis and elemental analysis (EL). The percentage of saturated hydrocarbon、aromatic hydrocarbon and H/C increased, and resin、asphalt and the amount of element of S,O and N decreased after the aquathermolysis. The changes of the composition and structure of the heavy oil can lead to the viscosity reduction and the improvement the quality of heavy oil. The results are very useful for the popularization and application of the new technology for the in situ upgrading of heavy oil by aquathermolysis.

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