(SoE) School of Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

This paper reports the novel synthesis of 5′-CMP molecule-mediated pH-responsive porous supramolecular hydrogels consisting of β-FeOOH/5′-CMP core-shell type nanohybrids as building blocks. The as-synthesized hydrogels have been fully characterized in terms of the size of the core and shape/morphology along with their optical, magnetic and rheological features. Interestingly, the gelation in the self-assembly is induced by the puckering of ribose sugar in the 5′-CMP molecule enhancing the intermolecular non-covalent interactions between 5′-CMP of different nanohybrids as well as β-FeOOH in a relatively narrow pH (5.5-7; 7-8.5) and temperature (35-40 °C) range. These changes have been analyzed by IR, Raman and CD spectroscopy. The viscoelastic nature of the optimized sample is revealed by fairly high values of viscosity (5.56 × 103 cP), G′ (4 × 104 Pa), G′′ (2.3 × 102 Pa) and yield strain (8.1%) with a linear viscoelastic region up to about 4%. A decrease in viscosity with shear rate demonstrates its gel like behavior matching with that of soft supramolecular hydrogels. The mechanism of gel formation has been thoroughly analyzed. pH, temperature and mechanical force induced spontaneous transition(s) of the sol into a hydrogel and its complete reversal into the sol suggest it to be a smart material. Thus, the soft hydrogels consisting of greener components such as a pyrimidine nucleotide (5′-CMP) and β-FeOOH phase, synthesized under physiological conditions of pH (7) and temperature (37 °C) with fairly high surface area, exhibited self-healing properties, injectability, relatively higher %swelling (530), and efficient loading (217 mg g-1) and release of adsorbed methylene blue (&gt;98%; model drug) over a period of more than 3 days in aqueous PBS buffer, suggesting them to be sustainable with significant potential in biological and environmental applications. © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

World University root node

Chemical Engineering

Fulltext

New Journal of Chemistry

Environmentally benign pH-responsive cytidine-5′-monophosphate molecule-mediated akaganeite (5′-CMP-β-FeOOH) soft supramolecular hydrogels induced by the puckering of ribose sugar with efficient loading/release capabilities

For electro-mechanical impedance (EMI) technique based Structural Health Monitoring (SHM), the piezo ceramic patches are employed with adhesive bond to evaluate and diagnose the host structure to be monitored. The adhesive bond forms a definite layer for force transmission between the patch and host structure. The mechanical and geometrical properties of the adhesive bond layer has significant effect on the overall performance of the PZT-structure interaction. This paper represents the effect geometrical deformation bonding area in the coupled admittance signature through mathematical modelling. The debonding effect has modelled for piezo elasto-dynamic system. In this paper, the mathematical modelling for 1D piezo elastic structure for debonding case and the results are compared with perfect bonding and definite bonding of adhesive bond for PZT-Structure interaction. The paper also studied parametric variation of bond parameter to examine the influence on the EMI based structural signature. © 2019 IEEE.

Civil Engineering

7th International Youth Conference on Energy, IYCE 2019

One-Dimensional Modelling of Piezo-Structure Interaction for DeBonding Configuration using Electro-Mechanical Impedance (EMI) Techniques

Fresh water is one of the essential requirements for the human being. To ensure the availability of potable water for the society is a big challenge due to limited availability of potable water on the Earth. Solar desalination systems can be used for mitigating the scarcity of desalted water in remote areas where sunlight is available in abundance. It works on the simple principle of evaporation and condensation. These systems are almost maintenance free and zero running cost which can be fabricated by materials readily available in the local market. The various designs of passive solar stills are used to increase the efficiency and productivity of distillate. In the present work, different types of specially designed single basin solar stills have been reviewed to find out the performance based on its efficiency, productivity and economy. Various novel models have also been observed for better view of relative performance among all solar stills to establish its clear utility indications as well. The observations have been concluded with broad perspective and some recommendations have also been suggested for the future scope for developing new designs to meet the possible challenges. © 2019 International Solar Energy Society

Mechanical Engineering

Solar Energy

Performance analysis of specially designed single basin passive solar distillers incorporated with novel solar desalting stills: A review

In this study, we demonstrate a novel pathway to engineer the properties of metallic alloys for limiting their cavitation erosion-corrosion. A facile single-step processing technique was used to develop bimodal grain structure in stainless steel. The bimodal steel was tested in cavitation erosion and erosion-corrosion conditions. In both the cases, bimodal steel showed exceptionally high degradation resistance, nearly 7 times higher compared to as-received steel. The remarkable cavitation erosion resistance demonstrated by bimodal steel is attributed to its high yield strength along with high work-hardening rate. In addition, the bimodal steel showed significantly low corrosion rate of 0.001 mm/year in 3.5 wt \% NaCl solution compared to 0.088 mm/year for as-received stainless steel. © 2019 Elsevier Ltd

Tribology International

Exceptional cavitation erosion-corrosion behavior of dual-phase bimodal structure in austenitic stainless steel

India currently has 5264 large dams in operation and 437 large dams under construction. Many of these dams do not match the emerging hydro-meteorological, hydraulic aspects. Safety of these dams is important to prevent collapse triggered by climate change effects. The increase in inflows to dams due to cloud bursts may cause dam safety concerns due to enhanced hydrodynamic forces. The main focus of this review is to get an insight into the events of cloud burst and GLOF which threaten dam safety. There are 65 completed and 11 under construction dams in India in the category of "Dams of National Importance" of which 22\% of the completed projects are older than 25 years. The review on failure due to cloud burst on few dams nationally and internationally has been done. The behaviour of Tehri Dam and Nathpa Jhakri dam in the past during the Cloud burst and GLOF occurrences and the importance to have a storage capacity for the hydel dams has been discussed along with the discussion on the necessity to increase the spillway capacity of Matatila dam. The scientific tools for conducting incisive case studies are highlighted to develop adaptive measures to deal with the resulting circumstances. © 2019, Central Board of Irrigation and Power. All rights reserved.

Center for Environmental Sciences & Engineering

Water and Energy International

Review of climate change impacts on dam safety and flood mitigation issues in India

Slurry and cavitation erosion often limits the durability of many fluid machines such as hydroturbines, pumps, and propellers. Despite good resistance against slurry erosion, thermal spray coatings generally exhibit poor resistance against cavitation erosion. The performance of thermal spray coatings under cavitation erosion is limited by the presence of defects such as pores, splat boundaries, and limited adhesion with the substrate. In the present work, we performed post-processing of the WC-10Co-4Cr and Ni coatings deposited using the detonation gun process. For post-processing, microwave technique was used owing to its capability for atomic-level heating. The microstructural characterization of the as-sprayed and post-processed coatings showed significant homogenization for the latter. Compared to the typical lamellar structure of as-sprayed, the processed samples exhibited a columnar structure with metallurgical bonding with the substrate. The mechanical properties of the coatings were significantly improved after post-processing owing to the elimination of splat boundaries and pores which significantly enhanced the cavitation and slurry erosion resistance. Post-processed coatings showed at least ten times higher resistance to cavitation erosion. The slurry erosion resistance of the coatings also improved up to three times depending upon the impingement angle. A significant difference in the erosion mechanism was also observed after post-processing. © 2019, ASM International.

Journal of Thermal Spray Technology

Microwave-Assisted Post-processing of Detonation Gun-Sprayed Coatings for Better Slurry and Cavitation Erosion Resistance

Bit error rate (BER) and channel capacity are two important metrics to assess the performance of free-space optical communication (FSOC) systems. Due to the fading of the optical signal owing to the atmospheric effects, these two quantities behave as random variables. Most of the studies in this direction have focused on the calculation of only the average of these quantities. However, since the complete information about a random variable is encoded in its distribution, it is more informative to examine the latter itself. In this work, the authors derive exact probability density function (PDF) expressions for the BER and the channel capacity for an arbitrary irradiance model. In particular, they investigate these exact results for log-normal, gamma-gamma, and K distributions. For the BER analysis, they focus on the binary phase shift keying and quadrature phase shift keying modulation schemes. The authors' analytical reults are found to be in conformity with Monte Carlo simulations. The exact PDFs of the BER and the channel capacity reveal that there are several instances when the average is unable to capture the actual behaviour of these quantities, and therefore one must be careful in drawing conclusions based on the first moment only. © The Institution of Engineering and Technology 2019

Physics

(SoNS) School of Natural Sciences

Computer Science and Engineering

IET Communications

Exact distributions for bit error rate and channel capacity in free-space optical communication

A MIMO antenna using dual - band planar antenna with rectangular slothas been proposed. The edge cleaving reduces the width of patch in comparison with conventional rectangular patch antenna designed at the same frequency, while its gain and radiating efficiency is noticeably improved. Measured results of the proposed antenna exhibits resonant frequency at 3.6GHz and 5.48GHz with an impedance bandwidth of 100MHz and 130MHz respectively. Further, the antenna is used as a radiating element for the design of 2-Element MIMO system. © 2019 IEEE.

Electrical Engineering

2019 6th International Conference on Signal Processing and Integrated Networks, SPIN 2019

Dual Band Slot Antenna for MIMO Applications

Drying a droplet containing microparticles results in the deposition of particles in various patterns, including the so-called "coffee-ring" pattern. The particle deposition is dependent on the internal flow dynamics, such as the capillary flow and Marangoni vortex (MV), of the droplet. Particle migration and self-assembly on a substrate are interesting phenomena that have critical implications in many applications such as inkjet printing, coating, and many other droplet-based industrial processes. In this work, we observed the formation of bands of particles in a rotating MV during the evaporation of a water droplet containing particles. We investigated the mechanism underlying the formation of banded MV caused by capillary meniscus forces between two particles near the air-liquid interface. In particular, we show that the banded MV can be manipulated by tuning the surfactant concentration and particle concentration. Our findings would provide a new direction in understanding the particle deposition pattern of a colloidal droplet. © 2019 American Chemical Society.

Langmuir

Dynamical Clustering and Band Formation of Particles in a Marangoni Vortexing Droplet

This study evaluated the change in physical and chemical properties of sun-dried food waste, during torrefaction in a fixed bed reactor. Torrefaction was carried out at different temperatures 230 °C, 260 °C, and 290 °C, for different residence times of 15, 30, 45, 60, 75, and 90 min in a fixed bed reactor. The solid torrefied products were analyzed by elemental analysis, proximate analysis, compositional analysis, and thermogravimetric analysis (TGA), and it was found that most suitable residence time for torrefaction was 60 min as torrefaction beyond 60 min did not yield much improvement in changing the properties of kitchen food waste. Carbon content increased from 46.0 to 58.5\%, consecutively increasing higher heating value (HHV) from 16.1 to 21.9\%. Compositional analysis demonstrated that there was not much hemicellulose left in the raw food waste after cooking; however, it had cellulose in significant proportion which went through decomposition during torrefaction. Lignin was not affected much. Various process parameters such as mass yield, energy yield, and energy density were also studied, and it was found the mass and energy yield decreased by 65.0\% and 47.5\%, respectively, and energy density increased by 35\%. Van Krevelen indicated clearly that torrefied char had achieved coal characteristics. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.