332 research outputs found
Growth of two-dimensional materials and Investigation of their structural and electronic properties.
Get PDFMy research activities focused on the growth and characterisation of two-dimensional materials. Initially Physical Vapour Deposition (PVD) growth of single layer (SL) MoS2 on Au(111) was performed by dosing Mo in H2S atmosphere at room temperature followed by annealing (Temperature Programmed Growth (TPG)) and we studied the evolution of intermediate species during the transformation by measuring fast-XPS. Thereafter by careful tuning the growth parameters, we developed a new procedure that leads to the direct growth of high quality SL MoS2 by dosing Mo in H2S atmosphere at high temperature (High Temperature Growth (HTG). Besides the improved quality of the layer the HTG growth method results in just one single orientation of the layer, leading to complete out-of plane spin polarisation in Spin-resolved ARPES measurements, whereas TPG produced a mixture (70:30) of two opposite orientations.
We studied the growth of SL WS2 on Au(111) by following the HTG method. In-situ fast XPS allowed to find the proper growth parameters leading to singly oriented WS2 high quality layer. The absence of partially sulfided peaks in the W 4f and S 2p core levels and sharp LEED spots indicated the high quality of the grown layer that was also reflected in the ARPES measurements that presented sharper bands than previously reported values and allowed the observation of moirè-induced mini gaps and the quantification of branch-dependent electron-phonon coupling strength.
MoS2 growth on Ag(111) was also performed by HTG method and resulted in the formation of two 180° rotated domains in equal proportion, as seen with LEED and XPD. LEED pattern indicated a very high structural order of the layer supported by the STM measurements. The Mo 3d core level presented a larger asymmetry than that measured for MoS2/Au(111) which is likely due to a semiconductor to metal transition of the MoS2 layer due to the strong interaction with the Ag(111) substrate.
HTG growth of SL MoS2 on Ag(110) was performed to explore the effect of the different substrate geometry on the properties of MoS2. The resulting layer was of very high quality, as determined with XPS, LEED, STM and ARPES measurements. The LEED and XPD patterns showed the presence of equal proportions of two mirror domains. A structural model for the relative arrangement of the hexagonal MoS2 lattice with respect to the rectangular lattice of the substrate was obtained based on LEED and STM measurements.
In order to study the reported growth of Silicene on Ir(111), the adsorption of Si on Ir(111) was studied for Si coverages up to more than one monolayer and characterized by high-resolution XPS and LEED. Experiments and DFT calculations showed dominant Si adsorption at the hollow sites together with segregation into the surface and even bilayer formation at high coverage, thereby implying the instability of Si/Ir(111) interface towards Si-Ir alloys, rather than formation of silicene layer
Understanding the India-Myanmar relations
Get PDFOn October 2, 2020, India and Myanmar participated in the 19th round of Foreign Office Consultations. This took place virtually, and new means of cooperation were discovered with India being represented by Foreign Secretary, Harsh Vardhan Shringla and Myanmar being represented by Permanent Secretary, U Soe Han
Periodic Modulation of Graphene by a 2D-FeO/Ir(111) Moiré Interlayer
No full textUltrathin films of iron oxide form a two-dimensional (2D) FeO layer on Ir(111). Because of difference in lattice constant between 2D-FeO and Ir(111), a moiré superstructure is formed. The 2D-FeO/Ir(111) structure is examined by soft X-ray photoelectron spectroscopy, X-ray photoemission diffraction, scanning tunneling microscopy, and low-energy electron diffraction. A 2D-FeO layer may also be grown by iron intercalation and subsequent oxidation underneath a graphene layer on Ir(111). Thus, the graphene can be decoupled from the metal by the 2D-FeO layer. Changes in the graphene C 1s binding energy can be mainly explained by shifts in the Fermi level of graphene as a consequence of interface band alignment for weak interactions between graphene and the substrate. A shift of C 1s to lower binding energy, for graphene supported on FeO/Ir(111), is a consequence of the dipole moment in the 2D-FeO layer normal to the Ir(111) surface. Broadening of the C 1s peak is consistent with a locally varying 2D-FeO dipole within the moiré structure and thus implies a modulated charge doping of the graphene
Waste-to-Energy Projects (Part II): : Comparing Approaches
No full textRapid urbanisation and industrialisation have led to a huge increase in the generation of municipal solid waste (MSW) across the globe. The world’s cities generate about 1.3 billion tons of solid waste per year and this is expected to increase to 2.2 billion tons by 2025. The most common method of waste management adopted by cities is to dispose of MSW in open dumps and oversaturated landfills. The improper management of MSW has become a threat to public and environmental health. However, this waste can also be perceived as an opportunity and a source of energy through Waste to Energy (WtE) technology. WtE technologies are used to produce various by-products like electricity, heat, biofuels and compost. In developed nations, it is primarily the non-organic elements of MSW that are used in WtE incineration. Developing nations are also investing heavily in WtE incineration, irrespective of the fact that their MSW consists primarily of biodegradables. The existing WtE incineration plants in India and China are not only causing heavy pollution but also posing a serious threat to the environment and human health. In this article, the author focuses on the current status and challenges of different WtE technologies used in Europe, US, China, Japan and India. Furthermore, the author recommends that waste incineration should not be treated as a source of renewable energy and suggests anaerobic digestion methods (biomethanation) as a solution for countries with more biodegradable waste.</p
Impact of Quality Management and Process Integration on Supply Chain Performance in Indian Automotive Industry
No full textFocus of this thesis is to empirically validate the impact of quality management and process integration on supply chain performance with reference to Indian automotive industry. Extensive literature review and citation analysis helped in identification of top management commitment and supplier relationship management as vital quality management and process integration constructs that impact the supply chain performance (upstream supply chain flexibility and customer satisfaction) of automotive organizations. Moreover, research gap emphasizes that process simplification has a mediating impact on the relationship between quality management and process integration constructs, and supply chain performance. Research gap helped in formulation of the hypothesized relationships as well as the conceptual framework (presented below).
The conceptual framework highlights that simplified processes mediates the impact of quality management and process integration (top management commitment and supplier relationship management) on supply chain performance (upstream supply chain flexibility and customer satisfaction) issues of automotive organizations. Both researchers and corporate executives alike have focused on fact that integrated and then simplified upstream supply chain processes lead to removal of redundant manufacturing processes, reduction in complexity of the process and an increase in manufacturing responsiveness. Therefore, there is a requirement to blend quality management and process integration for improving the supply chain performance of organizations.
A research instrument was prepared based on the valuable feedback from industry and academia. This process helped to ensure comprehensiveness, clarity, face validity and readability of the scale. Snowball sampling methodology was used to collect data from automotive organizations on a five point Likert Scale (Strongly Disagree - Strongly Agree). PROWESS database was used to calculate the average financial standalones of the selected firms from 2012 to 2015. Results confirmed that substantial automotive market is captured to represent Indian automotive sector.
Correlation analysis resulted in statistically validating interrelationships between the study constructs. Confirmatory factor analysis was performed on the sample size of eighty as per HOELTER's criterion and the good of fit summary confirms the measurement model as good fit. At last, structural equation modeling is executed on the measurement model to confirm direct and indirect effects of measured and latent variables. Results confirmed the mediating impact of process simplification in all relationships except on the relationship between top management commitment and upstream supply chain flexibility. The mediating impact clearly highlights that Indian automotive units must have a strategic focus towards simplifying the upstream integrated quality processes to improve the upstream supply chain flexibility and customer satisfaction issues. The simplified upstream integrated quality processes may enable Indian automotive units to gain competitive advantage by capturing substantial market.
Managerial implications of this research gives strategic directions to top level managers of automotive organizational on how to improve the automotive supply chain performance. Whereas, theoretical contributions guides future researchers with new aspects in theory for improving the upstream supply chain flexibility and customer satisfaction issues.
Vital contribution of this thesis to literature is that a unique validated measurement model is proposed that caters the mediating impact of process simplification on the relationships between quality management and process integration constructs, and supply chain performance
Science Communication for Transforming India
Get PDFScience films and science literature play a very important role in science communication, said Dr. Harsh Vardhan, Hon’ble Minister of Science & Technology, Earth Sciences and Environment, Forest & Climate Change. He also added that he dreamt of a day when science films would be the first choice of entertainment of the common man. Dr. Harsh Vardhan was speaking at the conclusion of the International Science Literature & Film Festival held at the Atal Bihari Vajpayee Scientific Convention Centre, Lucknow during 6-8 October 2018
Mathematical Modeling of the Texture of a Model Snack Food
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
One world one sun one grid: : a (modi)fication in India’s environment
No full text With a growing population and its needs, India is moving towards more pollution and less non-renewable resources left for the future generations. In this chaotic state, one thing certain is that India’s power requirement will grow. Renewable energy plays a significant role in providing sustainable and clean energy and mitigating climate change. As energy lies at the heart of the climate dilemma, producing 100 GW of solar energy by 2022 is a commendable but ambitious goal of India under Paris Accord of Climate Change. It is evident that the development of the Indian solar energy sector hinges on the combination of legislative framework, financial mechanisms, local manufacturing sector, environmentally sound technology, etc. Despite the growing impetus of solar energy in India, there are still gaps in its governance. In this article, the author focuses on the current status, challenges and future prospects of solar energy development in India and sums up the way forward with recommendations to address some of these gaps.</p
Optogenetic control of developmental signaling pathways
Get PDFHow a complex multicellular organism forms from a single cell is a question that defies simplistic understanding. Yet, embryonic developmental programs use a surprisingly small set of signaling pathways to pattern the embryonic tissue into germ layers from which the various tissues and organs emerge. A hallmark of embryonic development is that these recurring developmental signaling pathways are carefully orchestrated in space and time to facilitate proper development. Understanding the spatiotemporal intricacies of these pathways necessitates tools which enable their perturbation in precisely defined spatiotemporal patterns. Optogenetics uses light-induced conformational changes to enable or disable protein-protein interactions, thereby permitting control of signal transduction at the flip of a switch. Consequently, light is emerging as a powerful tool to study embryonic development owing to its rapid, reversible and residue-free application, which empowers the researcher with excellent spatial and temporal control of signaling. Here, I first review recent accomplishments in optical microscopy and optogenetics which highlight the dual roles of light in visualizing as well as perturbing cellular microenvironments and processes. Second, I present an optogenetic approach to control the mitogen-activated protein kinase (MAPK) pathway which we successfully applied in both neuroblasts and frog embryos. Third, I demonstrate an optogenetic approach to control the Wnt signaling pathway in mammalian cells and frog embryos. Finally, I propose and provide working proof for a generalizable optogenetic platform to control those developmental signaling pathways, the activities of which involve the homo-association of plasma membrane-localized receptor tyrosine kinases.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-12-01The student, Vishnu Vardhan Krishnamurthy, accepted the attached license on 2019-11-27 at 10:27.The student, Vishnu Vardhan Krishnamurthy, submitted this Dissertation for approval on 2019-11-27 at 10:29.This Dissertation was approved for publication on 2019-12-04 at 10:19.DSpace SAF Submission Ingestion Package generated from Vireo submission #14554 on 2020-02-28 at 17:36:14Made available in DSpace on 2020-03-02T22:38:43Z (GMT). No. of bitstreams: 3
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Covalent Organic Frameworks as an Organic Scaffold for Heterogeneous Catalysis including C-H Activation
No full textLinking small organic molecules into an extended solid usually afford disordered amorphous polymers. The instigation of order into such a material is of profound interest to induce inherent fine control of the overall structure. Covalent organic frameworks (COFs) are new class of porous crystalline material prepared by connecting organic building blocks via strong covalent bonds. The judicious choice of organic monomers can give rise to highly ordered and predictable frameworks with high crystallinity, surface area, and thermal/chemical stability. The role of connecting linkages such as B─O, C─C, C─N extends the principle of fundamental molecular covalent chemistry to the formation of crystalline materials. Among the diverse family of organic building blocks, bipyridine, catechol, and 2-phenylpyridine has gained attraction as organic monomer due to its excellent binding affinity with various transition metal ions. The metal ions, vanadium, palladium, and iridium were adopted to construct modified hybrid porous materials through pore surface engineering of frameworks.
In this dissertation, the role of pore surface engineering in covalent organic frameworks to form hybrid porous materials as heterogeneous catalysts for critical organic and organometallic conversions are demonstrated. Vanadium-modified frameworks (VO-TAPT-2,3-DHTA and VOPyTTA-2,3-DHTA) were synthesized by the reaction of catechol decorated COFs (TAPT-2,3-DHTA and PyTTA-2,3-DHTA) with vanadyl acetylacetonate. The hybrid porous materials serve as effective heterogeneous catalysts for Prins reaction, modified Mannich-type reaction, and sulfide oxidation (chapter 2). In addition to catechol decorated framework, bipyridine functionalized, Py-2,2´-BPyPh COF was used as scaffold to successfully immobilize iridium metal ions (Ircod(I)@Py-2,2´-BPyPh COF) to significantly broaden the spectrum of metal binding in this field. Ircod(I)@Py-2,2´-BPyPh COF acts as a reusable and recyclable catalyst for an effective C─H borylation reactions (chapter 3). The penultimate chapter of the dissertation illustrate an insight of metal docking via post synthetic modification of controllable bipyridine content of dual-pore imine-linked [(BPyDC)]x%-ETTA COFs (x = 0%, 25%, 50%, 75%, 100%), thereby imparts controlled palladium immobilization through binding with bipyridine units. The dual-pore palladium docked framework used as catalyst for C─H to C─O and C─X (X = Br, Cl) functionalization, which was compared with single pore palladium immobilized COF, Pd(II)@Py-2,2´-BPyPh to establish structure function relationship. Finally, in the last chapter of dissertation, first ever palladium-assisted intramolecular C─H functionalization, namely C─X (X = Cl, Br), C─O, and C─C within 2-phenylpyridine decorated PyTTA-FPPY framework is summarized.
Characterization of the pristine and modified porous frameworks includes powder X-ray diffraction (PXRD), surface area measurement at 77 K, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), solid state 13C CP-MAS NMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analysis, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance spectroscopy (EPR). In addition, intramolecular C─H functionalization were also studied by electrospray ionization-mass spectrometry (ESI-MS), and high-performance liquid chromatography (HPLC), which may provide ample opportunities to develop novel covalent organic framework, which are difficult to synthesize via de novo synthesis
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