S. Dinesh Kumar

Bio: S. Dinesh Kumar is an academic researcher from St. Peter's Engineering College, Avadi. The author has contributed to research in topics: Taguchi methods & Ultimate tensile strength. The author has an hindex of 17, co-authored 55 publications receiving 1059 citations. Previous affiliations of S. Dinesh Kumar include Virginia Tech & Indian Institute of Technology Madras.

Enhanced Electromagnetic Interference Shielding in a Au–MWCNT Composite Nanostructure Dispersed PVDF Thin Films

Abstract: Electromagnetic interference (EMI) shielding effectiveness and conductivities in a flexible conducting polymer composite film, prepared via a simple solvent cast method, of PVDF incorporated with Au–MWCNT are studied. The scanning electron microscopic analysis showed that the Au-loaded MWCNT uniformly dispersed in PVDF. The HRTEM images show that Au nanoparticles having a particle size of 20–30 nm have been deposited on the nodes of the MWCNT. The values of dielectric constant were found to be 12.11 and 13.89 at 1 MHz upon the incorporation of 1 and 3 wt % MWCNT in PVDF. The impedance and electromagnetic interference shielding effectiveness studies reveal that the polymer nanocomposites possess enhanced conductivity of 1.12 × 10–4 S/cm at 1 MHz, minimum return loss of 4.4 dB, and effective electromagnetic shielding of 26.7 dB at 12 GHz for 3 wt % Au NPs in 3 wt % MWCNT/PVDF thin film.

Promising Ti3C2Tx MXene/Ni Chain Hybrid with Excellent Electromagnetic Wave Absorption and Shielding Capacity.

Abstract: Electromagnetic (EM) pollution affecting people's normal lives and health has attracted considerable attention in the current society. In this work, a promising EM wave absorption and shielding material, MXene/Ni hybrid, composed of one-dimensional Ni nanochains and two-dimensional Ti3C2Tx nanosheets (MXene), is successfully designed and developed. As expected, excellent EM wave absorption and shielding properties are obtained and controlled by only adjusting the MXene content in the hybrid. A minimum reflection loss of -49.9 dB is obtained only with a thickness of 1.75 mm at 11.9 GHz when the MXene content is 10 wt %. Upon further increasing the MXene content to 50 wt %, the optimal EM shielding effectiveness (SE) reaches 66.4 dB with an absorption effectiveness (SEA) of 59.9 dB. Mechanism analysis reveals that the excellent EM wave absorption and shielding performances of the hybrid are contributed to the synergistic effect of conductive MXene and magnetic Ni chains, by which, the dielectric properties and electromagnetic loss can be easily controlled to obtain appropriate impedance matching conditions and good EM wave dissipation ability. This work provides a simple but effective route to develop MXene-based EM wave absorption and shielding materials. A universal guideline for designing the absorbing and shielding materials for the future is also proposed.

Flexible, Ultrathin, and High-Efficiency Electromagnetic Shielding Properties of Poly(Vinylidene Fluoride)/Carbon Composite Films.

Abstract: In this study, we fabricated conductive poly(vinylidene fluoride) (PVDF)/carbon composites simply by dispersing multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets into a PVDF solution The electrical conductivity and the electromagnetic interference (EMI) shielding of the PVDF/carbon composites were increased by increasing the conductive carbon filler amounts Moreover, we also found that the EMI shielding properties of the PVDF/CNT/graphene composites were higher than those of PVDF/CNT and PVDF/graphene composites The mean EMI shielding values of PVDF/5 wt %-CNT, PVDF/10 wt %-graphene, and PVDF/CNT/graphene composite films with a thickness of 01 mm were 2241, 1870, and 2758 dB, respectively An analysis of the shielding mechanism showed that the main contribution to the EMI shielding came from the absorption mechanism, and that the EMI shielding could be tuned by controlling the films’ thickness The total shielding of the PVDF/CNT/graphene films increased from 2190 to 3646 dB as the

An updated review of nanofluids in various heat transfer devices

Abstract: The field of nanofluids has received interesting attention since the concept of dispersing nanoscaled particles into a fluid was first introduced in the later part of the twentieth century This is evident from the increased number of studies related to nanofluids published annually The increasing attention on nanofluids is primarily due to their enhanced thermophysical properties and their ability to be incorporated into a wide range of thermal applications ranging from enhancing the effectiveness of heat exchangers used in industries to solar energy harvesting for renewable energy production Owing to the increasing number of studies relating to nanofluids, there is a need for a holistic review of the progress and steps taken in 2019 concerning their application in heat transfer devices This review takes a retrospective look at the year 2019 by reviewing the progress made in the area of nanofluids preparation and the applications of nanofluids in various heat transfer devices such as solar collectors, heat exchangers, refrigeration systems, radiators, thermal storage systems and electronic cooling This review aims to update readers on recent progress while also highlighting the challenges and future of nanofluids as the next-generation heat transfer fluids Finally, a conclusion on the merits and demerits of nanofluids is presented along with recommendations for future studies that would mobilise the rapid commercialisation of nanofluids

Ultrathin MXene/aramid nanofiber composite paper with excellent mechanical properties for efficient electromagnetic interference shielding

Abstract: MXenes, new two-dimensional compounds with hydrophilic surfaces and high metallic conductivity, have attracted significant interest in the electromagnetic interference shielding field in recent years. Nevertheless, poor mechanical properties and brittle nature are bottlenecks for their commercial application. Herein, one-dimensional ANFs were designed as the intermolecular cross-linker between d-Ti3C2Tx flakes and MXene (d-Ti3C2Tx)/aramid nanofiber (ANF) composite paper with a multi-layered structure was fabricated via the vacuum-assisted filtration approach. Further investigation revealed that the ANFs and MXene displayed good combination by hydrogen bonding, and MXene/ANF composite papers exhibited excellent mechanical properties and superior electrical conductivity. The MXene/ANF composite paper possessed a favorable shielding effectiveness (SE) which reached ∼28 dB in 8.2-12.4 GHz (X band) with an ultra-thin thickness ∼17 μm and showed potential application prospects as an advanced composite in sensitive electronic products.

Absorption-Dominated Electromagnetic Wave Suppressor Derived from Ferrite-Doped Cross-Linked Graphene Framework and Conducting Carbon

Abstract: To minimize electromagnetic (EM) pollution, two key parameters, namely, intrinsic wave impedance matching and intense absorption of incoming EM radiation, must satisfy the utmost requirements. To target these requirements, soft conducting composites consisting of binary blends of polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) were designed with doped multiwalled carbon nanotubes (MWCNTs) and a three-dimensional cross-linked graphene oxide (GO) framework doped with ferrite nanoparticles. The doping of α-MnO2 onto the MWCNTs ensured intrinsic wave impedance matching in addition to providing conducting pathways, and the ferrite-doped cross-linked GO facilitated the enhanced attenuation of the incoming EM radiation. This unique combination of magnetodielectric coupling led to a very high electromagnetic shielding efficiency (SE) of −37 dB at 18 GHz, dominated by absorption-driven shielding. The promising results from the composites further motivated us to rationally stack individual composites into a...