Geometrically Reconfigurable, 2D,All-Organic Photonic Integrated Circuits Made from Two Mechanically and Optically Dissimilar Crystals

With the rising concerns about global cybersecurity, safe data transduction that would be impervious to cyber attacks necessitates an immediate shift from electron-based to light-based devices. Here, the construction of silicon-free, all-organic photonic integrated circuits by micromanipulation of organic crystals of two mechanically different materials with complementary optical properties, one of which is plastically bendable, is described. The resulting optical circuits are endowed with mechanical reconfiguration at two levels: first, the individual components can be processed into arbitrary shape before integration into the circuit, and second, the circuit itself is reconfigurable even after it is fabricated. The results do not only demonstrate the infinite structural variations in optical microstructures one can build by using organic crystals, but they also show that deformable light-transducive organic crystals carry an untapped potential for lightweight all-organic optical minicircuitry.     

Performance investigation of a multi-stage sorption hydrogen compressor

Among several thermodynamic applications of metal hydrides, sorption hydrogen compressor (SHC) is more attractive for real-time application due to ease of construction and operation. In the present study, a four-stage sorption hydrogen compressor is proposed with detailed working principle for the compression output of >500 bar pressure. By adopting the screening methodology, four metal hydrides, i.e. La_0.9Ce_0.1Ni₅, Ti_0.99Zr_0.01V_0.43Fe_0.99Cr_0.05Mn_1.5, MmNi₅ and TiCrMn are selected for stages – 1, 2, 3 and 4 respectively with the supply temperature of 298 K and discharge temperatures of 373 K. The performance of sorption hydrogen compressor is estimated through finite volume approach and thermodynamic simulation in terms of variations in metal hydride bed pressure, temperature, hydrogen transmission, compressor work and efficiency. The numerical model is validated with experimentally measured metal hydride bed temperature and hydrogen concentration for single-stage hydrogen compressor, which are observed to be in good agreement. The cycle time of multi-stage SHC is predicted to be ~100 min with the maximum compression ratio of 73 with an overall efficiency of 10.62% employing 0.5 kg of each alloy and supply pressure of 9.5 bar. It is also observed that the discharge temperature greatly influences system performance. The dynamic performance of the system is also estimated with the implementation of simulation generated property data and observed that the performance parameters increased with the progression of hydrogen transmission.     

A novel CoN4-driven self-assembled molecular engineering for oxygen reduction reaction

The poor kinetics of oxygen reduction reaction (ORR) invites a quest for the development of low-cost and efficient non-Pt electrocatalysts for fuel cells. Herein, a nanocomposite (g-[Co₂N₈]) was synthesized by coordination assembly of CoN₄ macrocyclic moieties on graphene surface. The CoN₄ macrocyclic complex was characterized by UV–Vis, FT-IR, Mass, ¹H NMR and ¹³C NMR spectral studies, whereas UV–Vis, FT-IR, and Mass spectral, Raman, XRD and TEM studies were utilized to characterize the nanocomposite g-[Co₂N₈]. The results suggested that [CoN₄] units are present in self-assembled [Co₂N₈] species. Further, the nanocomposite g-[Co₂N₈] was examined for ORR activity by employing cyclic and linear sweep voltammetry and found that the formal potential (E_1/2) of g-[Co₂N₈] (+0.90 V) was more positive than 20% Pt/C (+0.86 V), indicating a remarkable ORR performance of g-[Co₂N₈] in comparison to 20% Pt/C, followed by 4e-mechanism. Moreover, the nanocomposite (g-[Co₂N₈]) displayed better ORR activity in comparison to [CoN₄] complex which can be attributed to the synergistic incorporation of endo and exo N₄–Co²⁺ moieties in the [Co₂N₈] species. In addition, g-[Co₂N₈] electrocatalyst exhibited a comparable stability to 20% Pt/C catalyst after 5000 cycles. This work will help to design multi-metallic coordination polymers with similar or different metal ions in N₄-arrangement for various energy related electrocatalysis.     

Enhanced non-linear optical properties of Eu3+ activated glasses by embedding silver nanoparticles

Tri-positive lanthanide ion (Eu³⁺) activated glasses doped with different concentrations of silver (Ag0₎ nanoparticles obtained using thermal reducing agent were fabricated by applying the method of melt quench. The formation of Ag⁰ nanoparticles in glasses was revealed by the surface plasmon resonance (SPR) peak in the absorption spectra. Transmission electron microscopic measurements confirmed the presence of spherically shaped Ag⁰ nanoparticles of different size distribution. The absorption spectra showed a red–shift of the SPR peak with an increase in AgNO₃ concentration occurring through Ostwald's ripening process because of the growth of particle size (as evidenced from microscope images). The non-linear optical (NLO) and optical limiting measurements were performed in the near infrared spectral region and femtosecond pulse excitation. The non-linear parameters were found to increase as the AgNO₃ concentration increased to 0.6 mol %, however, the parameters subsequently decreased at higher doping level. The optical limiting threshold values demonstrated a reverse trend. The increase in non-linear optical properties regarding Ag nanoparticles concentration attributed to the enhancement of polarizabilities of glasses that occurred through local field stimulated by SPR of Ag nanoparticles when exposed to laser radiation of high energy. The increase in NLO coefficients (particularly the non-linear absorption coefficient) and the decrease in optical limiting threshold values with AgNO₃ concentration (up to 0.6 mol %) indicated that these glasses containing 0.6 mol % AgNO₃ are useful for the construction of the power optical limiters that function at the infrared region in the femtosecond pulse regime.     

AIEMLA: artificial intelligence enabled machine learning approach for routing attacks on internet of things

The Journal of Supercomputing - The Internet of things (IoT) is emerging as a prime area of research in the modern era. The significance of IoT in the daily life is increasing due to the increase...     

Traversing the advantageous role of samarium doped spinel nanoferrites for photocatalytic removal of organic pollutants

The present work reportes the pertinence of samarium(Sm) doped spinel nanoferrites as magnetically recoverable photocatalyst for the removal of organic pollutants from wastewater.Thus,a series of Sm substituted spinel nano ferrites,MSm_xFe_(2-x)O_4(M=Ni,Co;x=0,0.02,0.06,0.1) we re synthesized via sol-gel methodology.The effect of Sm doping on the structural,morphological,optical and magnetic properties of pristine nanoferrites was investigated systematically.Further,the fabricated samples were explored as photocatalysts for the oxidative degradation of antibiotics(ofloxacin and norfloxacin) and dyes(methyl orange and safranin O).The Sm doped nanoferrites exhibit astonishing catalytic efficacy that can be attributed to higher surface area,octahedral site preference of Sm ions and reduced band gap.The synthesized nanoferrites display excellent recyclability which enables them to be utilized as potential photocatalysts for wastewater treatment.     

Magneto-hydrodynamic mixing: A new technique for preparing carbomer hydrogels

Magnetohydrodynamic mixing was evaluated as an alternative to conventional high shear mixing (HSM) in the preparation of carbomer hydrogels containing 1.22 wt% Carbopol® 980 NF. Neutralization of the carbomer dispersion (pH = 2.74) with triethanolamine (TEA) enabled to adjust the pH of the mixture and tune the viscosity of the hydrogel. Using HSM, this approach was limited to 0.2 wt% TEA (pH = 3.83) as the gel became too viscous and the recirculation flow dropped from 12 to 0.3 m³/h. Magnetohydrodynamic mixing enabled to reach TEA concentrations up to 1.0 wt% (pH = 5.31). Apparent viscosity measurements on samples having 0.2 wt% TEA revealed lower viscosities for carbomer hydrogels prepared with HSM, that is, 6800 mPa s versus 8800 mPa for magneto-hydrodynamic mixing. Based on ¹H NMR evidence, this decrease in apparent viscosity was attributed to structural damage to the carbomer backbone in combination with mechanochemical degradation of the added TEA.     

Synthesis,Characterization and Mechanical Properties of AA7075 Based MMCs Reinforced with TiB<Subscript>2</Subscript> Particles Processed Through Ultrasound Assisted In-Situ Casting Technique

AA7075/TiB₂ composites have been synthesized through both in situ salt-melt reaction method and ultrasound assisted in situ process. Microstructural studies reveals that ultrasound assisted in situ method improves the dispersion of TiB₂ particles and reduces the porosity level. Moreover, the ultrasonic treatment refines the reinforcement particle size along with improvement in particle dispersion. The mechanical property assessment confirms that ultrasonic treatment improves the mechanical properties of composite. The hardness of the AA7075 alloy is increased from 55 H_V to 74 H_V by the addition of 5% TiB₂ particles and it further increased to 82 H_V by ultrasonic treatment. A similar trend is also observed when weight percentage of particles increases to 7.5%. Addition of 5% in situ TiB₂ particles increases the ultimate tensile strength of AA7075 alloy by 60 MPa and it is further enhanced by 80 MPa upon ultrasound assisted process. Composites have shown a small reduction in ductility when compared to un-reinforced alloy, though 81% ductility of matrix alloy has been retained. Similar trend has been observed in composites fabricated using ultrasonic assisted casting.     

Performance Evaluation of Two Heat Transfer Models of a Walking Beam Type Reheat Furnace

Two different heat transfer models for predicting the transient heat transfer characteristics of the slabs in a walking beam type reheat furnace are compared in this work. The prediction of heat flux on the slab surface and the temperature distribution inside the slab have been determined by considering thermal radiation in the furnace chamber and transient heat conduction in the slab. Both models have been compared for their accuracy and computational time. The furnace is modeled as an enclosure with a radiatively participating medium. In the first model, the three-dimensional (3D) transient heat conduction equation with a radiative heat flux boundary condition is solved using an in-house code. The radiative heat flux incident on the slab surface required in the boundary condition of the conduction code is calculated using the commercial software FLUENT. The second model uses entirely FLUENT along with a user-defined function, which has been developed to account for the movement of slabs. The results obtained from both models have a maximum temperature difference of 2.25%, whereas the computational time for the first model is 3 h and that for the second model is approximately 100 h.     

Passive mechanical properties of ovine rumen tissue

Mechanical and structural properties of ovine rumen tissue have been determined using uniaxial tensile testing of tissue from four animals at five rumen locations and two orientations. Animal and orientation did not have a significant effect on the stress-strain response, but there was a significant difference between rumen locations. Histological studies showed two orthogonal muscle layers in all regions except the reticulum, which has a more isotropic structure. A quasi-linear viscoelastic model was fitted to the relaxation stage for each region. Model predictions of the ramp stage had RMS errors of 13–24% and were within the range of the experimental data.