Browsing by Author "Baheti, Vijay"

Now showing 1 - 13 of 13
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    Copper electroless plating of cotton fabrics after surface activation with deposition of silver and copper nanoparticles
    (Elsevier Ltd, 2020-02-01) Ali, Azam; Baheti, Vijay; Vik, Michal; Militký, Jiří
    In this work, surface metallization of cotton fabrics was performed by electroless plating using a shorter route than is conventional. The fabric surface was activated by deposition of silver and copper nanoparticles, and then a thin layer of copper was coated using electroless plating. The performance of coated fabrics was compared in terms of electrical conductivity, electromagnetic interference (EMI) shielding, Joule heating and antibacterial properties with another sample coated with conventional electroless plating. The orthogonal array testing strategy was adopted to optimize the various factors of the electroless plating bath. The samples prepared by electroless plating of copper showed greater performance for the fabric first deposited with silver particles than those first deposited with copper particles or conventionally treated. Samples of copper electroplating over silver had surface resistivity of 20 Ω, EMI shielding of 75.53 dB and Joule heating of 83.1 °C. Moreover, samples with modified electroless plating showed better attachment of the metal layer and therefore longer durability.
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    Development of electrically conductive composites based on recycled resources
    (2019-07-01) Ali, Azam; Baheti, Vijay; Khan, Muhammad Zaman; Ashraf, Munir; Militký, Jiří
    The current study was focused on the development of electrically conductive composites of carbon particle filled cotton fabric/epoxy systems. The carbon particles were refined to the scale of micro/nanoparticles using ball milling and morphological properties were studied by Malvern zetasizer and SEM. The influence of different concentrations of carbon particles in green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. Waveguide method at high frequency (i.e. at 2.45 GHz) was used to investigate the EMI shielding. Similarly, the effect of different concentrations of carbon particles in composites was also studied for mechanical strength (tensile and flexural). A comprehensive study showed the improvements in electrical and mechanical properties with increase in the concentration of carbon particles and their even distribution in resin. The composites with higher carbon filler concentration showed maximum electrical conductivity (1.0E-02), shielding effectiveness 23.13 dB and mechanical properties.
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    Electrical Conductivity of PLA Films Reinforced With Carbon Nano Particles from Waste Acrylic Fibers
    (2018-01-01) Naeem, Salman; Gilani, Syed Qummer Zia; Baheti, Vijay; Wiener, Jakub; Militký, Jiří; Javed, Saima; Ali, Azam; Javed, Zafar; ul Hassan, Syed Zameer
    The acrylic fibrous waste was effectively transformed into activated carbon through physical activation in single stage carbonization under charcoal using at different carbonization temperatures 800, 1000 and 1200 degrees C. The characterization of carbonized fibers was performed with the help of XRD and EDX in order to find out the degree of crystallinity and proportion of different elements in carbonized fibres prepared at different temperatures. Later on, the carbonized fibers were pulverized in dry conditions by high energy planetary ball milling to get activated carbon micro/nano particles. In addition to refinement of size, the electrical conductivity of pulverized carbon particles was found to increase with increase in milling time. Subsequently, the particles were incorporated into poly lactic acid (PLA) in different loadings from 1 to 10% to develop conductive green composite films The composite films were then characterized for electrical, thermo-mechanical and thermal properties.
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    Electrical Heating Properties of Carbon Fabric/Green Epoxy Composites Filled with Fly Ash
    (TEXTILE BIOENGINEERING & INFORMATICS SOCIETY LTD, TBIS 2010 SECRETARIAT MN104, HONG KONG POLYTECHNIC UNIV, HONG KONG SAR, 0000, PEOPLES R CHINA, 2019-01-01) Wang, Yuan-Feng; Karthik, Daniel; Yang, Kai; Yang, Tao; Xiong, Xiao-Man; Baheti, Vijay; Militký, Jiří
    This paper investigates the joule heating behavior and electrical property of the carbon fabric/green epoxy composite laminates filled with various concentrations of unmilled fly ash and milled fly ash. The infrared camera was used to record the change in surface temperature of composites over a period of time (i.e. from 0 to 240 sec) by varying the voltage from 0 to 10 V. The results show that the composite containing 0.5% fly ash exhibited the maximum temperature under different applied voltages. The maximum temperatures of epoxy/carbon composites could be finely tuned by controlling the concentrations of fly ash fillers as well as the applied voltage. When a certain voltage was applied to the composite, the surface composite temperature reached the maximum and became stable at a time shorter than 120s. In addition, the milled fly ash filled epoxy/carbon composites were found to reveal improvement in electrical heating performance and structural stability over the unmilled fly ash filled composites.
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    Energy harvesting performance of silver electroplated fabrics
    (ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2019-06-01) Ali, Azam; Baheti, Vijay; Militký, Jiří
    The objective of present study was to make electrically conductive multifunctional fabrics and their further use as electrodes for the development of triboelectric generator (TrEG). The conductive fabrics were made by the coating of thin copper layer and then electroplating of silver layer. The surface structure, electrical conductivity, hydrophobicity, and antibacterial properties of coated fabrics were examined to know their multifunctional properties. After silver electroplating, the fabrics depicted the electrical resistivity of 2 Omega mm as compared to 70 Omega mm electrical resistivity reported for the copper coating alone. Later, the energy harvesting performance of conductive fabric electrodes was studied by combining with oppositely charged triboelectric materials such as silicon rubber and rabbit fur. The fabricated TrEG was found to produce 21 V and 3.5 mu A current under the stretching action whereas 33 V and 6 mu A current under the pressing action. Furthermore, it charged the 1 mu F capacitor to 17 mV in 5 s. When its energy harvesting performance was investigated under the mechanical actions of human body, it generated about 10 V from elbow movements and about 40 V from foot movements.
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    Flame resistance behavior of cotton fabrics coated with bilayer assemblies of ammonium polyphosphate and casein
    (2019-03-01) Faheem, Sajid; Baheti, Vijay; Tunak, Maros; Wiener, Jakub; Militky, Jiri
    This research report discusses the intumescent flame resistance and physiological comfort of cotton fabrics after being coated with bilayer assemblies of different concentrations of ammonium polyphosphate (APP) and casein solutions. The flame resistance was investigated using horizontal flame propagation, cone calorimetry and thermo-gravimetric analysis, whereas physiological comfort was estimated in terms of air permeability, water vapor permeability and stiffness testing. From cone calorimetry results, the coated fabrics showed very slow combustion kinetics as the concentration of casein or APP was increased. Although, higher concentration of casein was found to produce higher char residue, but the physiological comfort properties were deteriorated beyond 5wt% casein. The images of burnt samples confirmed the formation of a distinct intumescence layer of char residue and it was also validated from the measurements of thermal conductivity of char residues. In this way, the presented work showed that the casein could perform number of functions such as catalyzed dehydration, accelerated charring and intumescent char formation in APP based intumescent systems.
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    Flame Retardancy, Physiological Comfort and Durability of Casein Treated Cotton Fabrics
    (2019-07-23) Faheem, Sajid; Baheti, Vijay; Nahid, Nazia; Tunak, Maros; Wiener, Jakub; Militký, Jiří
    The present work was aimed to develop the flame retardant textiles for prevention of second-degree burn injuries from low intensity heat flux accidents. The different concentration of casein suspension was applied on cotton fabrics and their thermo-oxidative properties, flame retardant behavior as well as physiological comfort were examined. From thermo gravimetric analysis, the percentage increase in char residue indicated improvement in thermo-oxidative properties. The maximum improvement in flame retardant behavior was found in case of 30 w/v % casein suspension due to higher production of thermally stable char. Their SEM micrographs also showed the formation of stronger and coherent char with presence of local intumescence. Furthermore, for estimating small differences in burn length and burn area, the flame propagation was studied in detail using the image analysis. The lower concentration of casein below 20 w/v % was found to provide adequate flame retardancy with acceptable physiological comfort and mechanical properties. Finally, the short term durability of casein treatment was verified under the effect of washing and ageing conditions.
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    Metal Coating on Ultrafine Polyester Non-woven Fabrics and Their Ageing Properties
    (2019-07-01) Ali, Azam; Baheti, Vijay; Militký, Jiří; Khan, Zaman; Zhu, Guocheng
    The presented research work proposed a simple technique to metalize the milife fabric (very fine thickness) with silver coating. The polyester fabrics were firstly sensitized with copper, and then silver plating was performed on the surface. The presence of silver over the fabric was observed by scanning electron microscope and respective EDX spectra. The change in the electrical conductivity, electromagnetic shielding and joule heating properties were examined for different electroplating time. The electrically conductive fabrics showed low electrical resistance with high EMI shielding over frequency range of 30 MHz to 1.5 GHz. To have an idea about the durability of electrical conductivity under stretch load, the 75 cycles of stretch and release were carried out. Furthermore, the heating performance of silver plated fabric was studied through measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. Lastly, the effect of ageing parameters like washing, oxidation and sulfidation were examined on the functional and comfort properties (i.e. thermal conductivity and stiffness) of conductive fabric.
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    Multifunctional polylactic acid composites filled with activated carbon particles obtained from acrylic fibrous wastes
    (2019-02-01) Naeem, Salman; Baheti, Vijay; Militký, Jiří; Ali, Azam
    The objective of this work was to explore the potentials of porous and electrically conductive activated carbon particles for possible enhancement of multifunctional properties of PLA. The activated carbon was inexpensively prepared from acrylic fibrous wastes by novel single stage carbonization and physical activation. The influence of 800 degrees C, 1,000 degrees C, and 1,200 degrees C carbonization temperature on physical, morphological, and electrical properties was studied from EDX, X-ray diffraction, SEM, and BET analysis. Later, the carbonized acrylic fibrous waste was pulverized in dry conditions by high energy planetary ball milling to get activated carbon particles. The particles were then incorporated into PLA under 1, 5 and 10 wt% loading to prepare composite films by solvent casting, and their electrical conductivity, EMI shielding, thermo-mechanical, and thermal stability properties were investigated.
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    Preparation of Hybrid Tapes for Fabrication of Composites
    (TEXTILE BIOENGINEERING & INFORMATICS SOCIETY LTD, TBIS 2010 SECRETARIAT MN104, HONG KONG POLYTECHNIC UNIV, HONG KONG SAR, 0000, PEOPLES R CHINA, 2018-01-01) Venkataraman, Mohanapriya; Militký Jiří; Baheti, Vijay; Mishra, Rajesh; Pulíček, Roman; Novotná, Jana; Samková, Alžběta; Voleská, Karolína; Srb, Pavel
    Technical fabrics, especially glass tows, are increasingly used for reinforcement of composites, due to its good mechanical properties. In this paper, glass fiber-based tapes containing special types of resins (in pre-condensate form) were prepared. This could be used for the preparation of composites using precise winding technique. The tensile properties of the tapes made from glass were investigated. Measurements were focused on the breaking force, deformation at break and initial modulus. It was also found that the durability of the tapes was sufficient for long term storing. The major benefit was the avoidance of resin penetration in the winded structure. This was achieved by the tight arrangements of fibrous phase which is very complicated. Also, the resins were loaded by suitable types of nanoparticles to enhance mechanical properties. The results showed a significant difference between the samples.
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    Studies on Organic and Inoganic Micro/nano Particle Reinforced Epoxy Composites
    (TEXTILE BIOENGINEERING & INFORMATICS SOCIETY LTD, TBIS 2010 SECRETARIAT MN104, HONG KONG POLYTECHNIC UNIV, HONG KONG SAR, 0000, PEOPLES R CHINA, 2018-01-01) Karthik, Daniel; Baheti, Vijay; Militký, Jiří; Palanisamy, Sundaramurthy
    Nanocomposites are a new class of composites that are particle-filled polymers where at least one dimension of the dispersed particles is in the nanometer range. The objective of this work is to investigate the potential use of reinforcement of different organic and inorganic micro/nano fillers in epoxy composites and to study effect oscillation frequency on dynamic mechanical properties of these composites. It was observed that the addition of micro/nano fillers improved the modulus of matrix. Damping behaviour changes with the type of filler incorporated confirms the fact that damping of composite material depends on the damping properties of constituents.
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    Superhydrophobicity, UV protection and oil/water separation properties of fly ash/Trimethoxy(octadecyl)silane coated cotton fabrics
    (Fiber Society, 2019-01-01) Khan, Muhammad Zaman; Baheti, Vijay; Militký, Jiří; Ali, Azam; Viková, Martina
    The presented study proposed simple and low-cost approach for improvement in UV protection and superhydrophobic properties of cotton fabrics by coating of mechanically activated fly ash particles. The maximum UV blocking was observed for 3 wt% fly ash, where UV transmittance decreased from 14.19% of untreated fabric to 0.11% of coated fabric. After subsequent treatment of Trimethoxy(octadecyl)silane (OTMS) on fly ash coated fabrics, the water contact angle was increased to 143° 147° and 153° for fly ash concentration of 1, 2 and 3 wt% respectively. From Cassie-Baxter theories, the unwetted fraction of air pockets were estimated to be 43%, 55% and 67% respectively for 1, 2 and 3 wt% of fly ash particles. Furthermore, the coated fabrics showed great potentials for separation of floating oil layer, underwater oil droplet or oil/water mixture. The separation efficiency of 98%, 96%, 97% and 95% was obtained for selected model oils toluene, n-hexane, chloroform and petro ether, respectively.
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    Surface Modification of Textile Fibers by Whiskerization
    (Technická univerzita v Liberci, 2019-01-01) Hassanin, Ahmed H.; Wang, Yuanfeng; Khan, Muhammad Zaman; Baheti, Vijay; Militký, Jiří