(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

Gaseous ammonia (NH3) is the most abundant alkaline gas in the atmosphere. In addition, it is a major component of total reactive nitrogen. The largest source of NH3 emissions is agriculture, including animal husbandry and NH3-based fertilizer applications. Other sources of NH3 include industrial processes, vehicular emissions and volatilization from soils and oceans. Recent studies have indicated that NH3 emissions have been increasing over the last few decades on a global scale. This is a concern because NH3 plays a significant role in the formation of atmospheric particulate matter, visibility degradation and atmospheric deposition of nitrogen to sensitive ecosystems. Thus, the increase in NH3 emissions negatively influences environmental and public health as well as climate change. For these reasons, it is important to have a clear understanding of the sources, deposition and atmospheric behaviour of NH3. Over the last two decades, a number of research papers have addressed pertinent issues related to NH3 emissions into the atmosphere at global, regional and local scales. This review article integrates the knowledge available on atmospheric NH3 from the literature in a systematic manner, describes the environmental implications of unabated NH3 emissions and provides a scientific basis for developing effective control strategies for NH3. © 2013 Springer-Verlag Berlin Heidelberg.

Civil Engineering

World University root node

Environmental Science and Pollution Research

Ammonia in the atmosphere: A review on emission sources, atmospheric chemistry and deposition on terrestrial bodies

In this paper decision variables for the key-frame detection problem in a video are evaluated using statistical tools derived from the theory of design of experiments. The pixel-by-pixel intensity difference of consecutive video frames is used as the factor or decision variable for designing an experiment for key-frame detection. The determination of a key-frame is correlated with the different values of the factor. A novel concept of meaningfulness of a video key-frame is also introduced to select the representative key-frame from a set of possible key-frames. The use of the concepts of design of experiments and the meaningfulness property to summarize a video is tested using a number of videos taken from MUSCLE-VCD-2007 dataset. The performance of the proposed approach in detecting key-frames is found to be superior in comparison to the competing approaches like PME based method (Liu et al., IEEE Trans Circuits Syst Video Technol 13(10):1006-1013, 2003; Mukherjee et al., IEEE Trans Circuits Syst Video Technol 17(5):612-620, 2007; Panagiotakis et al., IEEE Trans Circuits Syst Video Technol 19(3):447-451, 2009). © Springer Science+Business Media, LLC 2011.

Computer Science and Engineering

Multimedia Tools and Applications

A design-of-experiment based statistical technique for detection of key-frames

Chemically functionalized maleic anhydride (MAH)-grafted polypropylene matrix has been used (in place of polypropylene as matrix with compatibilizer) to process banana fiber/chemically functionalized polypropylene (BF/CFPP) composites, without using any compatibilizer and without any fiber modification by Palsule process. Fiber/matrix interfacial adhesion generated, in-situ, due to interactions between BF and the MAH of the CFPP matrix has been established by Fourier transform infrared spectroscopy and scanning electron microscopy. Mechanical properties of the BF/CFPP composites developed by Palsule process with in-situ fiber/matrix interfacial adhesion in this study have been found to be higher than those of the matrix and it increases with increasing amounts of fibers in composites, and are better than properties of literature reported BF/polypropylene composites processed with compatibilizers. Measured modulus of BF/CFPP composites compares well with values predicted by rule of mixtures, Hrisch model, Halpin-Tsai equations and its modified Nielsen version, and with Palsule equation. The feasibility of developing natural fiber/MAH grafted polyolefin composites by Palsule process without using any compatibilizer and without any fiber treatment is demonstrated. © 2013 Taylor and Francis Group, LLC.

Chemical Engineering

Composite Interfaces

Banana fiber/chemically functionalized polypropylene composites with in-situ fiber/matrix interfacial adhesion by Palsule process

The mass production of printed electronic devices can be achieved by roll-to-roll system that requires highly regulated web tension. This highly regulated tension is required to minimize printing register error and maintain proper roughness and thickness of the printed patterns. The roll-to-roll system has a continuous changing roll diameter and a strong coupling exists between the spans. The roll-to-roll system is a multi-input-multi-output, time variant, and nonlinear system. The conventional proportional-integral-derivative control, used in industry, is not able to cope with roll-to-roll system for printed electronics. In this study, multi-input-single-output decentralized control scheme is used for control of a multispan roll-to-roll system by applying regularized variable learning rate backpropagating artificial neural networks. Additional inputs from coupled spans are given to regularized variable learning rate backpropagating artificial neural network control to decouple the two spans. Experimental results show that the self-learning algorithm offers a solution to decouple speed and tension in a multispan roll-to-roll system. © IMechE 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions. nav.

Mechanical Engineering

Fulltext

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

Web tension control of multispan roll-to-roll system by artificial neural networks for printed electronics

In the current investigation, friction stir processing (FSP) of aluminium alloy 6061 alloy was carried out under different cooling conditions to determine its influence on the microstructure evolution and properties of the investigated alloy. It was found that the type and distribution of the strengthening precipitates in the friction stir processed Al 6061 alloy significantly depend on the FSP parameters and working temperatures during FSP. The properties of friction stir processed alloy were evaluated using micro-hardness and bulk hardness tests. It was observed that 6061 alloy friction stir processed under rapid cooling conditions exhibited enhanced hardness which was found to vary between nearly 12 to 33% as compared to the alloy processed under ambient cooling conditions. © (2013) Trans Tech Publications, Switzerland.

Advanced Materials Research

Effect of microstructural evolution on the properties of friction stir processed al 6061 alloy under different cooling conditions

Friction stir processing (FSP) is a material processing technique recognized to enhance the mechanical properties of the material owing to micro-structural refinement. In the present study, the feasibility of the use of FSP for processing of mild steel has been explored. Using FSP, the micro-structural refinement of the steel surface was obtained, resulting in an average grain sizes of the order of 100 nm as confirmed by atomic force microscopy (AFM). Along with grain size refinement, an evolution of various phases was also studied with the help of X-ray diffraction (XRD). It was observed that ferrite was the only phase present in both processed and unprocessed steel.FSP was found to be useful to enhance the micro-hardness of the steel by 50 to 80%, in comparison with that of the un-processed steel. © (2013) Trans Tech Publications, Switzerland.

Friction stir processing of mild steel to enhance its surface hardness

High power light emitting diode (LED) arrays have been investigated as excitation sources for long pulse and lock-in thermography. Images of artificial defects in a carbon fibre reinforced plastic (CFRP) composite sample are compared, by image contrast signal-to-noise ratio estimates, with those obtained using conventional incandescent flash and lock-in excitation sources. The LED arrays had to be mounted on heat sinks with active cooling in to prevent them exceeding their thermal tolerance. Despite this cooling the LED arrays were still found to emit some IR radiation, although far less than conventional incandescent light sources. © 2013 Elsevier Ltd.

Electrical Engineering

NDT and E International

LED optical excitation for the long pulse and lock-in thermographic techniques

Color stability in multi-emissive layer organic light emitting devices (Me-OLEDs) has been investigated. Me-OLEDs were based on multiple emitters with a common host CBP doped with three dopants, BCzVBi, Ir(ppy)3 and Ir(btp)2acac for blue, green and red emission. A major variation in CIE coordinates were found from (0.312, 0.294) to (0.236, 0.267) with increase in voltage from 6 to 9 V. This coordinate shift in Me-OLEDs has been attributed to the shifting of recombination zone with increase in voltage. In order to support our experimental observation, the EL spectrum of Me-OLEDs has been expressed as a linear combination of EL intensities of OLEDs with its individual constituting layers as emitters. In this way, the contribution of each layer in the EL spectrum of Me-OLEDs has been evaluated at each voltage. It has been observed from these calculations that the contribution of red emitter decreases from 47% to 33.33% and blue emitter increases from 38% to 51.67% with the increase in voltage from 6 to 9 V. This supports our hypothesis of shifting of recombination zone with the change in voltage. This shifting has been attributed to the field dependency of electron mobility in CBP. Me-OLED with CBP layers between the emitters was fabricated to improve the color stability. Significant improvement in color stability was achieved without changes in current efficiency in Me-OLED with interlayers. © 2012 Elsevier B.V.

Journal of Luminescence

Study of shifting of recombination zone in multi-emissive layer organic light emitting devices and its effect on color stability

In this Letter, the effect of F4-TCNQ insertion at the anode/hole transport layer (HTL) interface was studied on joule heating and the lifetime of organic light-emitting diodes (OLEDs). Joule heating was found to reduce significantly (pixel temperature decrease by about 10 K at a current density of 40 mA/cm2) by this insertion. However, the lifetime was found to reduce significantly with a 1 nm thick F4-TCNQ layer, and it improved by increasing the thickness of this layer. Thermal diffusion of F4-TCNQ into HTL leads to F4-TCNQ ionization by charge transfer, and drift of these molecules into the emissive layer caused faster degradation of the OLEDs. This drift was found to reduce with an increase in the thickness of F4-TCNQ. © 2013 Optical Society of America.

Optics Letters

Exciton quenching by diffusion of 2,3,5,6-tetrafluoro-7,7',8,8'-tetra cyano quino dimethane and its consequences on joule heating and lifetime of organic light-emitting diodes

The visualization of electromagnetic field intensity can be easily achieved by infrared thermography using an absorption screen of carbon loaded polymers. The electromagnetic waves falling on the absorption screen increase its temperature which is monitored by an infrared camera. The measured temperature profile can further be correlated to the electric field intensity. Measurement of electromagnetic field distribution is typically done by a small scanning antenna and is a time consuming process. Furthermore the scanning antenna will itself disturb the measurement process which is not the case with an absorption screen, even if the screen is kept very near to the electromagnetic wave source. Therefore fields very near to the source can also be visualized and measured. Also the length of the scanning antenna depends on wavelength of electromagnetic field to be measured, therefore it is improper to apply it to measure various fields. In order to show the utility of the above technique, an example of a patch antenna operating at a frequency of 2.45 GHz is given. Initial experiments show good agreement between simulated and measured results. © 2013 IEEE.