Selective oxidation of C4 hydrocarbons over (VO)2P2O7 catalyst: Nature of the redox mechanism

For the selective oxidation of n-butane to maleic anhydride, (VO)[subscript]2P[subscript]2O[subscript]7 has been identified as the most active and selective V-P-O phase. However, the presence of various types of oxygen species present in this polyfunctional system has made it difficult to study its redox mechanism in terms of the different oxygen species present. To overcome this problem, we have employed isotopic reactive-site mapping (IR-SM) approach. A three stage solid state procedure was used to synthesize a (VO)[subscript]2P[subscript]2O[subscript]7 catalyst labeled with [superscript]18O. Characterization of this labeled catalyst by infrared and Raman spectroscopies, along with other complimentary techniques allowed to determine the location and the extent of the [superscript]18O labeling in the lattice oxygen sites. This evidence pointed to a highly site-specific [superscript]18O labeling. Anaerobic pulse micro-reactor studies using C[subscript]4 hydrocarbons (n-butane, 1-butene) as reactants were conducted with this labeled catalyst. [superscript]18O incorporation into the oxygenated products was determined by mass spectrometry. A comparison between the [superscript]18O content of products to those in various catalyst lattice sites allowed to associate specific surface layer reactive sites with the different mechanistic steps in the selective and nonselective pathways for n-butane conversion by (VO)[subscript]2P[subscript]2O[subscript]7 catalyst. These studies further revealed that n-butane is irreversibly chemisorbed and activated at the vanadyl dimer sites in a highly specific manner. Oxygen insertion at nearby V-O/[superscript] P-V sites leads to form a furan-like surface species, which undergoes additional oxygen addition at P-O-V sites forming maleic anhydride. More than one nonselective pathways were evident: either by the direct combustion of n-butane, involving its cracking at V = O sites; or by the consecutive oxidation of the reaction intermediates and maleic anhydride. Reactivity of a site was found to be dependent on the nature of the hydrocarbon feed. Thus, the initial interaction of n-butane was found to be fundamentally different as compared to that of 1-butene. Quantitative measurements showed that participation of the bulk oxygen is limited, and the redox mechanism is thus limited to a few near surface monolayers

Effect of V-shaped Ribs on Internal Cooling of Gas Turbine Blades

Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperature. The rotor inlet temperatures in most gas turbines are far higher than the melting point of the blade material. Hence the turbine blades need to be cooled. In this work, simulations were carried out with the leading edge of gas turbine blade being internally cooled by coolant passages with V-shaped ribs at angles of 30°, 45° or 60° and at three aspect ratios (1:1, 1:2 and 2:3). The trailing edge of the blade was cooled by cylindrical and triangular pin-fin perforations in staggered and inline arrangements. Numerical analyses were carried out for each configuration of the cooling passages. The best cooling passages for leading edge and trailing edge were deduced by comparing the results of these analyses. It was found that using V-shaped ribs and fins induces a swirling flow, which in turn increases the velocity gradient and hence produces an improvement in heat transfer. The results show that under real time flow conditions, the application of V-shaped ribs and pin-fin perforations is a very promising technique for improving blade life

Demystifying Artificial Intelligence based Digital Twins in Manufacturing- A Bibliometric Analysis of Trends and Techniques

Nowadays, data is considered as a new life force for operations of physical systems in various domains such as manufacturing, healthcare, transportations, etc. However, the hugely generated data, which mirrors the working essence of the product life cycle, is still underutilised. Digital Twin (DT), a collective representation of active and passive captured data, is a virtual counterpart of the physical resources that could help prevent effective preventive maintenance in any applied domain. Currently, lots of research is going on about the applicability of digital twin in smart IOT based manufacturing industry 4.0 environment. Still, it lacks a formal study, which can provide a bird\u27s eye view about the research efforts and directions. In this paper, the authors represent a bibliometric survey of the digital twin concept based on the Scopus database to present a global view about scholars\u27 contributions in the manufacturing area. The study was conducted by retrieving 844 Scopus research papers published from 2015-2020 and analysed to find out critical insights such as publication volume, co-authorship networks, citation analysis, and demographic research distribution. The study revealed that significant contribution is made via concept propositions in conferences and some papers published in the journal. However, there is a scope of lots of research work in the direction of actual and secure digital twin implementation

3rd Zonal Workshop on Fisheries and Aquaculture Policy: Responsible Fisheries and Sustainable Aquaculture Perspectives for West Coast States Goa, Gujarat, Karnataka, Kerala, Maharashtra, and Union Territories of Daman and Diu, Dadra & Nagar Haveli and Lakshadweep

3rd Zonal Workshop on Fisheries and Aquaculture Policy: Responsible Fisheries and Sustainable Aquaculture Perspectives for West Coast States Goa, Gujarat, Karnataka, Kerala, Maharashtra, and Union Territories of Daman and Diu, Dadra & Nagar Haveli and Lakshadweep 21-23 June, 200

Predictive maintenance of bearing machinery using simulation- a bibliometric study

Modelling is a way of constructing a virtual representation of software and hardware that involves a real-world device. We will discover the behaviour of the system if the software elements of this model are guided by mathematical relationships. For testing conditions that may be difficult to replicate with hardware prototypes alone, modelling and simulation are particularly useful, especially in the early phase of the design process when hardware might not be available. Model-based approach in MATLAB-Simulink can be useful for predictive maintenance of machines as it can reduce unplanned downtimes and maintenance costs when industrial equipment breaks. Through this bibliometric paper, we carefully investigated the previously done research with the help of a number of papers from the Scopus Database. An overall analysis of the papers has been carried out to identify the extent of research done in this domain and understand the nature of the research work carried out considering the evolution of various predictive maintenance strategies being developed in recent years

Catch composition and discards in set bagnets of Karanja Estuary, Raigad, Maharashtra

Dol netting is one of the major fishing methods used mainly by traditional fishermen of Maharashtra. Study of catch composition of dol nets operated in Karanja Estuary of Raigad district, Maharashtra was carried out during September 2016 - May 2017. A total of ten single-day dol-netters were selected for the purpose of this study. Fortnightly on-board sampling and questionnaire-based sampling were carried out to fulfil the objectives of the study. The number of fishing days per month ranged from 12-16 due to tide-based restrictions. Dol net catch comprised 50 species of fin fishes, 3 species of elasmobranchs, 13 species of shrimps, 10 species of crabs, 5 species of cephalopods, 2 species of jellyfish, 4 species of sea snakes, 1 species of lobster and 2 species of stomatopods. Major catch composition of dol nets recorded during the study included Acetes indicus, Arius maculatus, Charybdis callianassa , Chrysaora Caliparea, Coilia dussumieri , Harpadon nehereus , Lepturacanthus savala , Miyakella nepa, Mystus gulio and Parapenaeopsis sculptilis. Significant discards such as jellyfishes, juveniles of several fishes and plastics were recorded in the dol nets operated in the Karanja estuar

Selective oxidation of C4 hydrocarbons over (VO)2P2O7 catalyst: Nature of the redox mechanism

For the selective oxidation of n-butane to maleic anhydride, (VO)[subscript]2P[subscript]2O[subscript]7 has been identified as the most active and selective V-P-O phase. However, the presence of various types of oxygen species present in this polyfunctional system has made it difficult to study its redox mechanism in terms of the different oxygen species present. To overcome this problem, we have employed isotopic reactive-site mapping (IR-SM) approach. A three stage solid state procedure was used to synthesize a (VO)[subscript]2P[subscript]2O[subscript]7 catalyst labeled with [superscript]18O. Characterization of this labeled catalyst by infrared and Raman spectroscopies, along with other complimentary techniques allowed to determine the location and the extent of the [superscript]18O labeling in the lattice oxygen sites. This evidence pointed to a highly site-specific [superscript]18O labeling. Anaerobic pulse micro-reactor studies using C[subscript]4 hydrocarbons (n-butane, 1-butene) as reactants were conducted with this labeled catalyst. [superscript]18O incorporation into the oxygenated products was determined by mass spectrometry. A comparison between the [superscript]18O content of products to those in various catalyst lattice sites allowed to associate specific surface layer reactive sites with the different mechanistic steps in the selective and nonselective pathways for n-butane conversion by (VO)[subscript]2P[subscript]2O[subscript]7 catalyst. These studies further revealed that n-butane is irreversibly chemisorbed and activated at the vanadyl dimer sites in a highly specific manner. Oxygen insertion at nearby V-O/[superscript] P-V sites leads to form a furan-like surface species, which undergoes additional oxygen addition at P-O-V sites forming maleic anhydride. More than one nonselective pathways were evident: either by the direct combustion of n-butane, involving its cracking at V = O sites; or by the consecutive oxidation of the reaction intermediates and maleic anhydride. Reactivity of a site was found to be dependent on the nature of the hydrocarbon feed. Thus, the initial interaction of n-butane was found to be fundamentally different as compared to that of 1-butene. Quantitative measurements showed that participation of the bulk oxygen is limited, and the redox mechanism is thus limited to a few near surface monolayers.</p

Enhancing Surface Fault Detection Using Machine Learning for 3D Printed Products

In the era of Industry 4.0, the idea of 3D printed products has gained momentum and is also proving to be beneficial in terms of financial and time efforts. These products are physically built layer-by-layer based on the digital Computer Aided Design (CAD) inputs. Nonetheless, 3D printed products are still subjected to defects due to variation in properties and structure, which leads to deterioration in the quality of printed products. Detection of these errors at each layer level of the product is of prime importance. This paper provides the methodology for layer-wise anomaly detection using an ensemble of machine learning algorithms and pre-trained models. The proposed combination is trained offline and implemented online for fault detection. The current work provides an experimental comparative study of different pre-trained models with machine learning algorithms for monitoring and fault detection in Fused Deposition Modelling (FDM). The results showed that the combination of the Alexnet and SVM algorithm has given the maximum accuracy. The proposed fault detection approach has low experimental and computing costs, which can easily be implemented for real-time fault detection

Estimation of virological and immunological parameters in subjects from South India infected with human immunodeficiency virus type 1 clade C and correlation of findings with occurrence of neurological disease

Several studies carried out in Western countries have demonstrated that a number of virological and immunological markers such as viral loads, cytokines, β2-microglobulin, neopterin, etc., are elevated in the serum and cerebrospinal fluid (CSF) of human immunodeficiency virus (HIV)-infected individuals with neurological disease. The neurological manifestations of HIV infection noted in Indian patients is different from those reported in Western countries. Moreover, few studies have investigated the role of virological and immunological parameters with respect to the progression of HIV-1 clade C infection in India. In this study, we measured virological (HIV-1 RNA levels) and immunological parameters (CD4 cell count and inflammatory markers) in the plasma and CSF of HIV-1-infected neurologically asymptomatic and symptomatic (with opportunistic infections and/or dementia) subjects. By using clade-specific polymerase chain reaction (PCR), we ascertained that all samples used for the study were infected with HIV-1 clade C. Among the various laboratory parameters evaluated, high viral loads in the CSF, low CD4 counts, and higher levels of interleukin (IL)-1α, IL-6, tumor necrosis factor alpha (TNFα), β2-microglobulin, and neopterin were noted in HIV-infected subjects with neurological disease as compared to asymptomatic subjects. These data suggest that the markers evaluated in plasma and CSF samples correlated with occurrence of neurological disease in symptomatic individuals as compared to asymptomatic HIV infected subjects