Particle–fluid interactivity reduces buoyancy-driven thermal transport in nanosuspensions: A multi-component Lattice Boltzmann approach

ABSTRACT

Severe contradictions exist between experimental observations and computational predictions regarding natural convective thermal transport in nanosuspensions. The approach treating nanosuspensions as homogeneous fluids in computations has been pinpointed as the major contributor to such contradictions. To fill the void, inter-particle and particle–fluid interactivities (slip mechanisms), in addition to effective thermophysical properties, have been incorporated within the present formulation. Through thorough scaling analysis, the dominant slip mechanisms have been identified. A Multi-Component Lattice Boltzmann Model (MCLBM) approach is proposed, wherein the suspension has been treated as a non-homogeneous twin component mixture with the governing slip mechanisms incorporated. The computations based on the mathematical model can accurately predict and quantify natural convection thermal transport in nanosuspensions. The role of slip mechanisms such as Brownian diffusion, thermophoresis, drag, Saffman lift, Magnus effect, particle rotation, and gravitational effects has been accurately described. A comprehensive study on the effects of Rayleigh number, particle size, and concentration revealed that the drag force experienced by the particles is primarily responsible for the reduction of natural convective thermal transport. In essence, the dominance of Stokesian mechanics in such thermofluidic systems is established in the present study. For the first time, as revealed though a thorough survey of the literature, a numerical formulation explains the contradictions observed, rectifies the approach, predicts accurately, and reveals the crucial mechanisms and physics of buoyancy-driven thermal transport in nanosuspensions.     

Organic photovoltaic devices based on pentacene/N,N′-dioctyl-3,4,9,10-perylenedicarboximide heterojunctions

We have studied an organic photovoltaic cell based on an efficient donor/acceptor combination of pentacene/N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C₈) heterojunctions. Photocurrent spectra exhibited excellent light harvesting throughout the visible spectrum with maximum external quantum efficiency (EQE) of ～60%. PTCDI-C₈ layer provided significant contribution to the photocurrent due to its strong absorption properties and efficient exciton dissociation at pentacene/PTCDI-C₈ interface. Power conversion efficiency of about 1.2% has been achieved under AM 1.5 illumination. The device showed a low series resistance of 18 Ω cm² and a high shunt resistance of 2.5 kΩ cm², resulting in a high fill factor of 65%.     

Physics & Modeling of Ambipolar Snapback Behavior in Gate Grounded NMOS

Silicon - This paper models first snapback ambipolar action in NMOS, when subjected to high current stress across the drain terminal. We analyze 2 − D ambipolar current in Gate Grounded NMOS...     

Bruton’s Tyrosine Kinase Targeting in Multiple Myeloma

Multiple myeloma (MM), a clonal plasma cell disorder, disrupts the bones’ hematopoiesis and microenvironment homeostasis and ability to mediate an immune response against malignant clones. Despite prominent survival improvement with newer treatment modalities since the 2000s, MM is still considered a non-curable disease. Patients experience disease recurrence episodes with clonal evolution, and with each relapse disease comes back with a more aggressive phenotype. Bruton’s Tyrosine Kinase (BTK) has been a major target for B cell clonal disorders and its role in clonal plasma cell disorders is under active investigation. BTK is a cytosolic kinase which plays a major role in the immune system and its related malignancies. The BTK pathway has been shown to provide survival for malignant clone and multiple myeloma stem cells (MMSCs). BTK also regulates the malignant clones’ interaction with the bone marrow microenvironment. Hence, BTK inhibition is a promising therapeutic strategy for MM patients. In this review, the role of BTK and its signal transduction pathways are outlined in the context of MM.     

Effects of Normal Synovial Fluid and Interferon Gamma on Chondrogenic Capability and Immunomodulatory Potential Respectively on Equine Mesenchymal Stem Cells

Synovial fluid contains cytokines, growth factors and resident mesenchymal stem cells (MSCs). The present study aimed to (1) determine the effects of autologous and allogeneic synovial fluid on viability, proliferation and chondrogenesis of equine bone marrow MSCs (BMMSCs) and (2) compare the immunomodulatory properties of equine synovial fluid MSCs (SFMSCs) and BMMSCs after stimulation with interferon gamma (INF-γ). To meet the first aim of the study, the proliferation and viability of MSCs were evaluated by MTS and calcein AM staining assays. To induce chondrogenesis, MSCs were cultured in a medium containing TGF-β1 or different concentrations of synovial fluid. To meet the second aim, SFMSCs and BMMSCs were stimulated with IFN-γ. The concentration of indoleamine-2,3-dioxygenase (IDO) and nitric oxide (NO) were examined. Our results show that MSCs cultured in autologous or allogeneic synovial fluid could maintain proliferation and viability activities. Synovial fluid affected chondrocyte differentiation significantly, as indicated by increased glycosaminoglycan contents, compared to the chondrogenic medium containing 5 ng/mL TGF-β1. After culturing with IFN-γ, the conditioned media of both BMMSCs and SFMSCs showed increased concentrations of IDO, but not NO. Stimulating MSCs with synovial fluid or IFN-γ could enhance chondrogenesis and anti-inflammatory activity, respectively, suggesting that the joint environment is suitable for chondrogenesis.     

Green hythane production from food waste: Integration of dark-fermentation and methanogenic process towards biogas up-gradation

This study presents an integration of acidogenesis (dark-fermentation) and methanogenesis for green hythane/biohythane production from food waste in two stages (S–I and S-II) and phases (P–I and P-II) of operational variations. The regulatory influence of biocatalyst and redox environment on anaerobic fermentation was evaluated  through a rapid protocol in the context of biogas up-gradation with reference to bio-hydrogen (bio-H₂), biomethane (CH₄), bio-hythane (H₂+CH₄) and their composition (H₂/(H₂+CH₄)) as major markers. Bioreactors with two different parent cultures (heat-shock pretreated and untreated) were operated at pH 6 and 7 in two phases to overcome the impediment of single-phase operation aiming for maximum energy recovery from the untreated substrate of P–I. Integration of S–I with S-II was beneficial to achieve 1.22 times higher cumulative bio-hythane production (4.25 L) compared to S–I (3.47 L) condition alone. The bio-hythane composition mimics the H₂ enriched CNG (H-CNG) and showed the potential to be implemented for biogas up-gradation as a tool.     

Recent advances in synthesis,characterization, and applications of nanoparticles for contaminated water treatment- A review

The major issue of consumable water shortage in different parts of the world has piqued the interest of researchers around the globe towards finding out novel, efficient and cost-effective means and techniques for treatment of contaminated water. Towards such efforts, researchers are experimenting with various types of nanoparticles for observing their abilities to treat polluted and/or wastewater. Numerous types of nanoparticles such as carbon-based nanoparticles, semiconductor nanoparticles, ceramic nanoparticles, polymeric nanoparticles, metal nanoparticles, magnetic nanoparticles, etc. are widely tested to confirm their applicability as potential candidates for contaminated as well as wastewater treatment. Different types of nanoparticles offer specific advantages depending on their composition, physical, chemical, electrical, magnetic and structural characteristics. Nanoparticles such as nanoferrites are reported to be easily separated, regenerated and reused up to several runs without incurring any loss in their properties which tend to significantly reduce operations costs. The present study provides a detailed review of the various synthesis and characterization techniques for the production of the nanoparticles. The present study also reviews the current progress, made particularly during the last two decades, in the application of nanoparticles for successful removal of organic, metallic as well as pathogenic pollutants from the water. This review aims to highlight the unlimited potential of nanoparticles and their derivatives in the domain of contaminated and wastewater treatment.     

Deep neural network to detect COVID-19: one architecture for both CT Scans and Chest X-rays

Applied Intelligence - Since December 2019, the novel COVID-19’s spread rate is exponential, and AI-driven tools are used to prevent further spreading [1]. They can help predict, screen, and...     

Image-based features for speech signal classification

Like other applications, under the purview of pattern classification, analyzing speech signals is crucial. People often mix different languages while talking which makes this task complicated. This happens mostly in India, since different languages are used from one state to another. Among many, Southern part of India suffers a lot from this situation, where distinguishing their languages is important. In this paper, we propose image-based features for speech signal classification because it is possible to identify different patterns by visualizing their speech patterns. Modified Mel frequency cepstral coefficient (MFCC) features namely MFCC- Statistics Grade (MFCC-SG) were extracted which were visualized by plotting techniques and thereafter fed to a convolutional neural network. In this study, we used the top 4 languages namely Telugu, Tamil, Malayalam, and Kannada. Experiments were performed on more than 900 hours of data collected from YouTube leading to over 150000 images and the highest accuracy of 94.51% was obtained.

     

Naturally occurring neem gum: An unprecedented green resource for bioelectrochemical flexible energy storage device

Naturally available neem tree gum consisting of bioelectrolyte and bioelectrode was fabricated for flexible energy storage device. Structural morphology, thermal stability, porosity and surface area of as prepared bioelectrode were characterized thoroughly by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) isotherm respectively. The bioelectrolyte conductivity was optimized under various concentrations of lithium ion salts and temperatures through electrochemical impedance spectroscopy (EIS). A flexible supercapacitor (SCs) was fabricated by using bioelectrodes and electrolyte and tested for its electrochemical properties. The supercapacitor displayed specific capacitance of 640 Fg^-1 and 200 Fg^-1 at a current density 0.5 Ag^-1 and 1.0 V operating potential window. The energy device has also demonstrated large operational window (2.0 V) and shown 102 Fg^-1 at a current density of 1.0 Ag^-1. The novelty of the present work lies in the simplified, cost-effective procedure for preparation of biomaterials, their remarkably high stability under strong mechanical bent and long-term charging-discharging cycles of the fabricated device.