ORCID Profile
0000-0001-9157-2589
Current Organisations
Massachusetts Institute of Technology
,
National Aeronautics and Space Administration
,
Eastern Engineering Solutions LLC
,
Eastern Publishers
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Publications
Detail design (DD), front end (FE), back end (BE) design of non-tactical deployable 20 GWh (17.20841 kilo ton TNT) plane wave lens configuration fusion device
Publisher: Research Square Platform LLC
Date: 09-11-2022
DOI: 10.21203/RS.3.RS-2244327/V3
Abstract: A simple plane wave lens, using an inert central plastic wave shaper, has been designed. An experiment was done with a 4 in diam, zeroth order design. An iterative technique that uses measured time deviations to connect the next wave shape was developed. Two identical versions of the first iterated shape were fired. Arrival time deviations in these first iterates fell within 50 ns bonds. With greater care and further iterations, lenses bound by 10 ns deviations seem possible. An advanced and novel integration method is applied. It is shown that this technique bears significant advantage over prior methods and is meritorious.
Detail design (DD), front end (FE), back end (BE) design of non-tactical deployable 20 GWh (17.20841 kilo ton TNT) plane wave lens configuration fusion device
Publisher: Research Square Platform LLC
Date: 02-12-2022
DOI: 10.21203/RS.3.RS-2244327/V4
Abstract: A simple plane wave lens, using an inert central plastic wave shaper, has been designed. An experiment was done with a 4 in diam, zeroth order design. An iterative technique that uses measured time deviations to connect the next wave shape was developed. Two identical versions of the first iterated shape were fired. Arrival time deviations in these first iterates fell within 50 ns bonds. With greater care and further iterations, lenses bound by 10 ns deviations seem possible. An advanced and novel integration method is applied. It is shown that this technique bears significant advantage over prior methods and is meritorious.
Silver cities: planning for an ageing population in Singapore. An urban planning policy case study of Kampung Admiralty
Publisher: Emerald
Date: 25-04-2022
DOI: 10.1108/ARCH-09-2021-0252
Abstract: This paper explores ways in which Singapore adapts its planning policy and practices to meet the needs of its growing silver population, particularly the relationship between ageing related policies and its urban development strategies. The research assesses Singapore's urban planning policies for the ageing population against the WHO framework for age-friendly cities using K ung Admiralty (KA) (a pioneering project of integrated housing cum community for the ageing population) as a case study for the analysis. The methodology adopted includes a post-occupancy evaluation and a walking tour of the selected case study (K ung Admiralty), and an analysis of Singapore's ageing policies in relation to urban planning governance. The study examines the role and significance of a multi-agency collaborative governance structure in ageing planning policies with erse stakeholders in the project. The evaluation carried out on KA reveals the challenges and opportunities in urbanisation planning for the ageing population. This paper concludes by emphasising the potential of multi-collaborative governance and policymaking in creating an inclusive, liveable built environment for the ageing population in Singapore, particularly but also potential implications for other ASEAN tropical cities. The case study identified key issues in Singapore's urban planning for betterment in ageing and highlighted the requirement for enhancing urban planning strategies. This article fulfils an identified need for the Singapore government to address the issue of ageing by providing affordable and silver-friendly housing to its ageing population.
Bulk Metallic Glasses and Their Composites
Publisher: De Gruyter
Date: 03-09-2021
Materials for outer shell of 1.170 GWh (1.00669 kilo ton TNT) fusion device - weight basis
Publisher: Research Square Platform LLC
Date: 17-01-2023
DOI: 10.21203/RS.3.RS-2478727/V1
Abstract: With recent developments in fusion engineering, interest has sparked in development of fusion devices for deterrent. Enormous amount of energy generated by combining two light nuclei could be contained and manipulated at will to trigger and accelerate micro explosions (from shock wave, x-rays or ion beam focusing) which finally result in full scale blast. Materials required to make such device are critical. They must possess high strength, high hardness, ductility, formability, drawability, and anisotropic properties. High entropy alloys (HEA) are new class of materials which nicely fulfils this requirement. Essentially, they are solid solutions of multi principal elements (usually 5) eliminating the need of base metal as in conventional alloys. This gives them many unique properties which may be tailored at will (heat treatment, cold rolling, precipitation, irradiation). They also exhibit excellent directional properties with formation of distinct bands along certain preferred crystallographic planes even in hexagonal close packed structures. These anisotropic properties are strong function of rolling, working, or forging (swaging) direction and can be utilized to benefit. This study encompasses making outer shell of a typical fusion device selected on the basis of the weight, which is a function of area of pay load bay of carrier aircraft.
Modeling and Simulation of Heat Transfer Phenomena
Publisher: InTech
Date: 29-07-2015
DOI: 10.5772/61029
Design of Non-Tactical Deployable 20 Gwh (17.20841 Kilo Ton TNT) Fusion Device - Energy Basis
Publisher: MDPI AG
Date: 16-01-2023
DOI: 10.20944/PREPRINTS202205.0284.V2
Abstract: Fusion device and its structure may be designed by various means. Two of most popular are weight basis (described in previous study by author) and energy basis. In present research, later method is explored and described. Energy basis is based on amount of energy released from device upon detonation followed by explosion. Its beneficial in a sense that device size can be kept as independent variable as compared to dependent in former case. Further, it shortens the design procedure. For ex le, heat transfer pattern in such approach directly helps in quantifying wall thickness which dictates material, fabrication, and manufacturing route. It may also eliminate anisotropy as wall thickness is direct function of amount of heat at which it will rupture and can be much thinner. Device geometry can also be flexibility controlled as it is no longer dependent on pay load bay capacity. This allows more freedom in designing subsystems (compartments, their locations, focusing, switches, and mixers). Such devices can be more compact and simpler. Few such design configurations are proposed.
Design of Non-Tactical Deployable 20 Gwh (17.20841 Kilo Ton TNT) Fusion Device - Energy Basis
Publisher: MDPI AG
Date: 23-05-2022
DOI: 10.20944/PREPRINTS202205.0284.V1
Abstract: Fusion device and its structure may be designed by various means. Two of most popular are weight basis (described in previous study by author) and energy basis. In present research, later method is explored and described. Energy basis is based on amount of energy released from device upon detonation followed by explosion. Its beneficial in a sense that device size can be kept as independent variable as compared to dependent in former case. Further, it shortens the design procedure. For ex le, heat transfer pattern in such approach directly helps in quantifying wall thickness which dictates material, fabrication, and manufacturing route. It may also eliminate anisotropy as wall thickness is direct function of amount of heat at which it will rupture and can be much thinner. Device geometry can also be flexibility controlled as it is no longer dependent on pay load bay capacity. This allows more freedom in designing subsystems (compartments, their locations, focusing, switches, and mixers). Such devices can be more compact and simpler. Few such design configurations are proposed.
Analytical Modeling and Computer Simulation of Heat Transfer Phenomena during Hydrothermal Processing Using SOLIDWORKS<sup>&#174;</sup>
Publisher: Scientific Research Publishing, Inc.
Date: 2020
Diffraction patterning using back scattering of electrons in Zr47.5Cu45.5Al5Co2 Bulk Metallic Glass Matrix Composites
Publisher: Research Square Platform LLC
Date: 14-03-2023
DOI: 10.21203/RS.3.RS-2679250/V1
Abstract: Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr 47.5 Cu 45.5 Al 5 Co 2 bulk metallic glass matrix composite during melting and solidification. Its effect is checked by detailed diffraction patterning using back scattering of electrons in scanning microscopy using a detector. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon pattern and map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Diffraction is observed and indicates towards presence of crystalline phases. Inoculation treatment is shown to be advantageous.
Modelling and Simulation of Solidification Phenomena during Additive Manufacturing of Bulk Metallic Glass Matrix Composites (BMGMC)—A Brief Review and Introduction of Technique
Publisher: Scientific Research Publishing, Inc.
Date: 2018
A Smart Way of Synthesis and Characterization of New DNA Based Hybrid Catalysts
Publisher: Bentham Science Publishers Ltd.
Date: 03-09-2018
Understanding Microstructural Evolution in ZrC Inoculated Zr47.5Cu45.5Al5Co2 Via High Resolution SIMS
Publisher: Oxford University Press (OUP)
Date: 08-2019
Plasma Facing Material by Self-Interstitial Solid Solution Strengthening – Problem, Proposition, and a Solution
Publisher: MDPI AG
Date: 12-10-2020
DOI: 10.20944/PREPRINTS202010.0258.V1
Abstract: Bubble (point defect) & ndash a precursor of fuzz or under dense nanostructure formation is crystal lattice defect. Suitable selection of crystal lattice which inhibit Frenkel pair generation and intrinsically promotes selfinterstitial solid solution strengthening contributes effectively towards making plasma facing material. For this, interstitial sites, their size, amount / fraction, positions, tendency of occupation and diffusion parameters (e.g. activation energies (Q), activation volumes) are determined. Fcc iron carbon alloys (austenitic stainless steels AISI / SAE 321, fcc structure, Pearson code cF4, space group Fm3̅m) are proposed as suitable candidates. Along with their room temperature fcc structure having 12 interstitial positions (4 octahedral, 6 coordination sites and 8 tetrahedral, 4 coordination sites / unit cell) to allow insertion of self (iron) atoms, they have excellent corrosion resistance, thermal conductivity, and nonmagnetic properties. After their melting, casting, and machining to required dimensions and geometry, stabilizing heat treatment is applied to precipitate all carbon as TiC and prevent formation of Cr23C6 (sensitization). This resist heat and surface degradation and yield excellent architecture which not only inhibit Frankel pair generation but will also allow bulk assimilation or surface annihilation (loop punching) of this lattice point defect. A superior thermal, fluid, and structural design augment above
Probabilistic Modeling and Simulation of Microstructural Evolution in Zr Based Bulk Metallic Glass Matrix Composites During Solidification
Publisher: Springer International Publishing
Date: 2018
Materials for Outer Shell of 1.170 GWh (1.00669 Kilo Ton TNT) Fusion Device - Weight Basis
Publisher: MDPI AG
Date: 29-10-2021
DOI: 10.20944/PREPRINTS202110.0446.V1
Abstract: With recent developments in fusion engineering, interest has sparked in development of fusion devices for deterrent. Enormous amount of energy generated by combining two light nuclei could be contained and manipulated at will to trigger and accelerate micro explosions (from shock wave, x-rays or ion beam focusing) which finally result in full scale blast. Materials required to make such device are critical. They must possess high strength, high hardness, ductility, formability, drawability, and anisotropic properties. High entropy alloys (HEA) are new class of materials which nicely fulfils this requirement. Essentially, they are solid solutions of multi principal elements (usually & 5) eliminating the need of base metal as in conventional alloys. This gives them many unique properties which may be tailored at will (heat treatment, cold rolling, precipitation, irradiation). They also exhibit excellent directional properties with formation of distinct bands along certain preferred crystallographic planes even in hexagonal close packed structures. These anisotropic properties are strong function of rolling, working, or forging (swaging) direction and can be utilized to benefit. This study encompasses making outer shell of a typical fusion device selected on the basis of the weight, which is a function of area of pay load bay of carrier aircraft.
Modeling and simulation of microstructural evolution in Zr based Bulk Metallic Glass Matrix Composites during solidification
Publisher: Springer Science and Business Media LLC
Date: 07-07-2017
DOI: 10.1557/ADV.2017.481
Diffraction patterning using back scattering of electrons in Zr47.5Cu45.5Al5Co2 Bulk Metallic Glass Matrix Composites
Publisher: Research Square Platform LLC
Date: 15-03-2023
DOI: 10.21203/RS.3.RS-2679250/V2
Abstract: Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composite during melting and solidification. Its effect is checked by detailed diffraction patterning using back scattering of electrons in scanning microscopy using a detector. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon pattern and map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Diffraction is observed and indicates towards presence of crystalline phases. Inoculation treatment is shown to be advantageous.
Diffraction patterning using back scattering of electrons in Zr47.5Cu45.5Al5Co2 Bulk Metallic Glass Matrix Composites
Publisher: Research Square Platform LLC
Date: 16-03-2023
DOI: 10.21203/RS.3.RS-2679250/V3
Abstract: Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composite during melting and solidification. Its effect is checked by detailed diffraction patterning using back scattering of electrons in scanning microscopy using a detector. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon pattern and map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Diffraction is observed and indicates towards presence of crystalline phases. Inoculation treatment is shown to be advantageous.
Lenvatinib plus Pembrolizumab or Everolimus for Advanced Renal Cell Carcinoma
Publisher: Massachusetts Medical Society
Date: 08-04-2021
Materials for Outer Shell of 1.170 Gwh (1.00669 Kilo Ton TNT) Fusion Device - Weight Basis
Publisher: MDPI AG
Date: 17-01-2023
DOI: 10.20944/PREPRINTS202110.0446.V2
Abstract: With recent developments in fusion engineering, interest has sparked in development of fusion devices for deterrent. Enormous amount of energy generated by combining two light nuclei could be contained and manipulated at will to trigger and accelerate micro explosions (from shock wave, x-rays or ion beam focusing) which finally result in full scale blast. Materials required to make such device are critical. They must possess high strength, high hardness, ductility, formability, drawability, and anisotropic properties. High entropy alloys (HEA) are new class of materials which nicely fulfils this requirement. Essentially, they are solid solutions of multi principal elements (usually & 5) eliminating the need of base metal as in conventional alloys. This gives them many unique properties which may be tailored at will (heat treatment, cold rolling, precipitation, irradiation). They also exhibit excellent directional properties with formation of distinct bands along certain preferred crystallographic planes even in hexagonal close packed structures. These anisotropic properties are strong function of rolling, working, or forging (swaging) direction and can be utilized to benefit. This study encompasses making outer shell of a typical fusion device selected on the basis of the weight, which is a function of area of pay load bay of carrier aircraft.
Retracted: Development of Bulk Metallic Glasses and their Composites by Additive Manufacturing – Evolution, Challenges and a Proposed Novel Solution
Publisher: Trans Tech Publications, Ltd.
Date: 21-08-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1155.1
Abstract: Bulk metallic glasses (BMGs) and their composites (BMGMCs) have emerged as competitive materials for structural engineering applications exhibiting superior tensile strength, hardness along with very large elastic strain limit. However, they suffer from lack of ductility and subsequent low toughness due to the inherent brittleness of the glassy structure which makes them amenable to failure without appreciable yielding. Various mechanisms and methods have been proposed to counter this effect out of which, recently Additive Manufacturing has gained widespread attention. It is proposed that additive manufacturing can overcome these difficulties in single step due to inherent existence of very high cooling rate in the process which is essential for glass formation. This, when coupled with careful selection of alloy chemistry is proposed to be the best solution to fabricate near net shape parts in a single step with excellent properties. In this report, an effort has been made to describe one possible route to achieve this. Solidification processing employing carefully selected inoculants based on edge to edge matching technique along with the carefuly controlled inoculation procedure is proposed to reflect upon enhanced mechanical properties. It is hypothesized that number density, size and distribution of ductile crystalline phase would best be able to improve microstructure and hence properties. This is meant to be controlled by manipulating type, size and the amount of inoculants. The proposed methodology is claimed to bear maximum potential.
Simulation of Solidification Parameters during Zr Based Bulk Metallic Glass Matrix Composite’s (BMGMCs) Additive Manufacturing
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Image analysis and Laser Particle Diffraction study of ProRoot-MTA, Portland cement and Bismuth Oxide-A comparative study
Publisher: Crimson Publishers
Date: 16-02-2018
Erratum to: Modeling and simulation of microstructural evolution in Zr based Bulk Metallic Glass Matrix Composites during solidification - CORRIGENDUM
Publisher: Springer Science and Business Media LLC
Date: 12-2020
DOI: 10.1557/ADV.2020.447
Production and Characterization of Zr Based Bulk Metallic Glass Matrix Composites (BMGMC) in the Form of Wedge Shape Ingots
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Hydrothermal Processing of Phase Pure and Doped Hydroxyapatite and its Characterization
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Probabilistic Modelling of Microstructural Evolution in Zr Based Bulk Metallic Glass Matrix Composites during Solidification in Additive Manufacturing
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Production of Carbon Nanotubes by Different Routes-A Review
Publisher: Scientific Research Publishing, Inc.
Date: 2011
Retracted: Development of Bulk Metallic Glass Matrix Composites (BMGMC) by Additive Manufacturing: Modelling and Simulation – A Review: Part B
Publisher: Trans Tech Publications, Ltd.
Date: 21-06-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1154.40
Abstract: . Bulk metallic glasses (BMGs) and their composites (BMGMC) have emerged as competitive materials for structural engineering applications exhibiting superior tensile strength, hardness along with very high elastic strain limit. However, they suffer from a lack of ductility and subsequent low toughness due to the inherent brittleness of the glassy structure which render them to failure without appreciable yielding owing to mechanisms of rapid movement of shear bands all throughout the volume of the material. This severely limits their use in the manufacture of structural engineering parts. Various theories and mechanisms have been proposed to counter this effect. Introduction of secondary ductile phase in the form of in-situ nucleating and growing dendrites from melt during solidification have proved out to be best solution of this problem. Nucleation and growth of these ductile phases have been extensively studied over the last 16 years since their introduction for the first time in Zr-based BMGMC by Prof. Johnson at Caltech. Data about almost all types of phases appearing in different systems have been successfully reported. However, there is very little information available about the precise mechanism underlying their nucleation and growth during solidification in a copper mould during conventional vacuum casting and melt pool of additively manufactured parts. Various routes have been proposed to study this including experiments in microgravity, levitation in synchrotron light and modelling and simulation. In this report, which is Part B of two parts comprehensive overview, state of the art of development, manufacturing, characterisation and modelling and simulation of BMGMCs is described in detail. Evolution of microstructure in BMGMC during additive manufacturing have been presented with the aim to address fundamental problem of lack in ductility along with prediction of grain size and phase evolution with the help of advanced modelling and simulation techniques. It has been systematically proposed that 2 and 3 dimensional cellular automaton method combined with finite element (CAFE) tools programmed on MATLAB® and simulated on Ansys® would best be able to describe this phenomenon in most efficient way. Present part B focuses on methodology by which modelling and simulation can be adopted and applied to describe evolution of microstructure in this complex class of materials.
On the Inoculation and Phase Formation of Zr<sub>47.5</sub>Cu<sub>45.5</sub>Al<sub>5</sub>Co<sub>2</sub> and Zr<sub>65</sub>Cu<sub>15&
Publisher: Trans Tech Publications, Ltd.
Date: 04-2020
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1158.43
Abstract: Bulk metallic glass matrix composites have emerged as new potential material for structural engineering applications owing to their superior strength, hardness and high elastic strain limit. However, their behaviour is dubious. They manifest brittleness and inferior ductility which limit their applications. Various methods have been proposed to overcome this problem. Out of these, introduction of foreign particles (inoculants) during solidification have been proposed as most effective. In this study, an effort has been made to delimit this drawback. A systematic tale has been presented which explain the evolution of microstructure in Zr 47.5 Cu 45.5 Al 5 Co 2 and Zr 65 Cu 15 Al 10 Ni 10 bulk metallic glass matrix composites with varying percentage of ZrC inoculant as analysed by secondary electron and back scatter electron imaging of as cast unetched s les. A support is provided to hypothesis that inoculation remain successful in promoting phase formation and crystallinity and improve toughness.
Modeling and Simulation of Heat Transfer Phenomenon Related to Mold Heating during Investment Casting
Publisher: Scientific Research Publishing, Inc.
Date: 2020
Pyrometallurgy and Electrometallurgy of Rare Earths – Part A: Analysis of Metallothermic Reduction and its Variants
Publisher: MDPI AG
Date: 18-03-2021
DOI: 10.20944/PREPRINTS202103.0463.V1
Abstract: Rare earths are classified as most important and critical material for US economy and defense by Congress and a mandate has been set to increase their in-house production, domestic resource utilization and decrease reliance on foreign resources and reserves. They are widely available in earth crust as ore (bastnaesite (La, Ce)FCO3, monazite, (Ce, La, Y, Th)PO4, and xenotime, YPO4), but their so-called economic reserves are sparsely located geographically. They may be produced by various means such as beneficiation (physical, chemical, mechanical, or electrical), reduction (direct or indirect), electrolysis (of aqueous or molten / fused single or mixed salt systems) at high temperature or hydrometallurgy. Out of these, direct reduction also known as metallothermic reduction (La and Ca reduction) is mostly utilized. Its variant, high temperature electrowinning of fused salts is also practiced widely. These processes are material and application specific. In this study, author will employ thermodynamics (Ellingham diagrams, free energy of formation, reduction potential, Nernst equation, Pourbaix (Eh-pH) diagrams, E-pO-2 diagrams), kinetics and energetic of a chemical reaction (chemical metallurgy) to reduce rare earth oxide / salt to rare earth metals (REO/RES & ndash REM). It is shown that materials and energy requirement vary greatly depending on type of mineral ore, production facility, and beneficiation / mineral processing method selected. Aim is to reduce dependence on coal deposits. It is anticipated this route will be able to produce rare earths with & 35% yield and & 98% purity which be described in subsequent studies and patents.
EBSD Microstructure Mapping of Zr47.5Cu45.5Al5Co2 Bulk Metallic Glass Matrix Composite to Ascertain the Effect of Inoculation in Promoting Crystallinity
Publisher: MDPI AG
Date: 24-04-2020
DOI: 10.20944/PREPRINTS201812.0159.V2
Abstract: Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composite during melting and solidification. Its effect in promoting crystallinity is checked by detailed electron back scatter diffraction (EBSD) mapping. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Inoculation treatment is shown to be advantageous.
EBSD Microstructure Mapping of Zr47.5Cu45.5Al5Co2 Bulk Metallic Glass Matrix Composite to Ascertain the Effect of Inoculation in Promoting Crystallinity
Publisher: MDPI AG
Date: 13-12-2018
DOI: 10.20944/PREPRINTS201812.0159.V1
Abstract: Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composite during melting and solidification. Its effect in promoting crystallinity is checked by detailed electron back scatter diffraction (EBSD) mapping. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Inoculation treatment is shown to be advantageous.
Pyrometallurgy and Electrometallurgy of Rare Earths – Part A: Analysis of Metallothermic Reduction and Its Variants
Publisher: Informa UK Limited
Date: 09-01-2023
Fracture of Be and its Alloys - Webb Space Telescope Revisited
Publisher: MDPI AG
Date: 16-01-2023
DOI: 10.20944/PREPRINTS202111.0503.V2
Abstract: NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (& alpha ) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.
Fracture of Be and Its Alloys - Webb Space Telescope Revisited
Publisher: MDPI AG
Date: 26-11-2021
DOI: 10.20944/PREPRINTS202111.0503.V1
Abstract: NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (& alpha ) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.
Effect of Single Pass Laser Surface Treatment on Microstructure Evolution of Inoculated Zr<SUB>47.5</SUB>Cu<SUB>45.5</SUB>Al<SUB>5
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Effect of Inoculation on Phase Formation and Indentation Hardness Behaviour of Zr<SUB>47.5</SUB>Cu<SUB>45.5</SUB>Al<SUB>5</
Publisher: Scientific Research Publishing, Inc.
Date: 2018
Modeling and simulation of heat transfer phenomena during investment casting
Publisher: Elsevier BV
Date: 03-2009
Modelling and Simulation of Microstructural Evolution for Extra-terrestrial Planetary Chemistry Mapping Using Artificial Intelligence – a NASA Mars Rover Study
Publisher: MDPI AG
Date: 23-07-2020
DOI: 10.20944/PREPRINTS202007.0566.V1
Abstract: Development of rovers and development of infrastructure which enables them to probe other planets (such as Mars) have sparked a lot of interest recently specially with increasing public attention in Moon and Mars program by National Aeronautics and Space Administration. This is designed to be achieved by various means such as advanced spectroscopy and artificial intelligent techniques such as deep learning and transfer learning to enable the rover to not only map the surface of planet but to get a detailed information about its chemical makeup in layers beneath (deep learning) and in areas around point of observation (transfer learning). In this work, which is part of a proposal, later approach is explored. A systematic strategy is presented which make use of aforementioned techniques developed for metallic glass matrix composites as benchmark and helps develop algorithms for chemistry mapping of actual Martian surface on Perseverance Rover launching shortly.
Non-Linear Analytical Modeling and Simulation of Microstructural Evolution in Zr Based Metallic Glass Matrix Composites During Solidification Using MATLAB® – Further Results
Publisher: MDPI AG
Date: 27-10-2020
DOI: 10.20944/PREPRINTS202010.0497.V1
Abstract: Metallic glass matrix composites are unique new materials which have superior mechanical properties as compared to existing conventional materials. Owing to this, they are potential candidates for various future structural applications. However, they suffer from disadvantages of brittleness, poor ductility and little or no toughness and they manifest catastrophic failure on application of force. Their behavior is dubious and require extensive experimentation to draw conclusive results. In present study, which is continuation of previous study by author, an effort has been made to overcome this pitfall by simulation. A quantitative mathematical model based on KGT theory has been developed to describe nucleation and growth of crystalline phase dendrites in glassy matrix during solidification. It yields information about numerical parameters to understand the behavior of each in idual element in a phase in multicomponent sluggish slurry and their effect on final microstructural evolution. Model is programmed and simulated in MATLAB& reg . Its validation is done by comparison with identical curves reported in literature previously for similar alloys. Results indicate that effect of incorporating all heat transfer coefficients at macroscopic level and diffusion coefficients at microscopic level play a vital role in refining the model and bringing it closer to actual experimental observations. Two types of hypoeutectic and eutectic systems namely Zr65Cu15Al10Ni10 and Zr47.5Cu45.5Al5Co2 respectively were studied. Simulation results were found to be in good agreement with prior simulated and experimental values
Fracture of Be and its alloys - Webb Space Telescope revisited
Publisher: Authorea, Inc.
Date: 09-01-2023
DOI: 10.22541/AU.167328367.73728053/V1
Abstract: NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (α) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.
Pyrometallurgy and Electrometallurgy of Rare Earths – Part B: Cell design, construction, rate processes, and unit operation
Publisher: Research Square Platform LLC
Date: 06-10-2022
DOI: 10.21203/RS.3.RS-2126620/V1
Abstract: Production of rare earths by metallothermic reduction and its variants is presented in an earlier study and its analysis is performed indicating major type and sequence of reactions. Diagrams required and procedures to establish them are also described. Their role and importance are also described. A comparison is also made to identify parameters of importance. This study is continuation of a previous study in which cell design to extract metals is described. Parameters to design and construct cell (metallothermic and electrothermic) are determined and used. Rate processes (heat transfer, mass transfer, charge transfer and simultaneous processes) occurring inside a cell, its operation for a specific reaction and sequence for a specific metal (Nd) are described. Outline of calculations outlining cell efficiency, output and yield are enumerated for in idual (Nd, Ce, Dy) metal. Optimization and method to achieve is described. Procedures to control and production is also described. Here preliminary graphs are presented.
Modelling and Simulation of Microstructural Evolution in Zr Based Bulk Metallic Glass Matrix Composites (BMGMC) in Additive Manufacturing – A Proposal, Opinion and Prospect
Publisher: MDPI AG
Date: 10-02-2023
DOI: 10.20944/PREPRINTS202302.0179.V1
Abstract: Despite being well established phenomena, solidification principles are experiencing tough challenges in their application to explain microscale transport phenomena in additive manufacturing melt pool. The problem becomes even more complicated when applied to multicomponent bulk metallic glass matrix composites (BMGMC) whose behavior is dubious and still not fully understood. The aim of the present study is to highlight pathways to overcome these challenges. A comprehensive nucleation and growth model based on original KGT theory and Rappaz modification is proposed encompassing actual transient thermophysical BMGMC data to predict evolving microstructure during additive manufacturing. The model is aimed at pictorial representation of in-situ ductile phase dendrite evolution from melt pool during solidification using two-dimensional cellular automaton (CA) methods. It is proposed to be coded in MATLAB& reg using commercial simulation code ABAQUS& reg at back end for macroscopic heat transfer model. The results will be compared with experimental values for validation.
Fiber-reinforced magneto-polymer matrix composites (FR–MPMCs)—A review
Publisher: Springer Science and Business Media LLC
Date: 14-03-2017
DOI: 10.1557/JMR.2017.63
Design of an impact testing machine for polymer films by the free falling dart procedure
Publisher: Walter de Gruyter GmbH
Date: 31-08-2015
DOI: 10.3139/120.110779
Abstract: Impact forces have been used to study the behavior of materials for a long time. The aim of the impact testing is to investigate those conditions under which a material will fail in a brittle manner regarding a sudden load. There are three general methods of testing impact resistance of components: falling weight tests, pendulum tests and tumbling impact tests. In the present study, an attempt has been made to establish an impact tester used to carry out impact testing of plastic films by free falling dart method. In this, a box of wood with a hole on its upper side is used on which plastic film is held by cl s and a dart is allowed to fall onto film to note perforation. Then the impact resistance is statistically calculated. Impact resistance is determined by the energy caused by weight to fail 50 % of specimen. Practical results are found to be in good agreement with theory.
Development of Model and Simulation of Heat Transfer Phenomena during Hydrothermal Processing Using SOLIDWORKS®
Publisher: MDPI AG
Date: 19-07-2020
DOI: 10.20944/PREPRINTS202007.0412.V1
Abstract: Hydrothermal /super critical processes are important process to synthesize materials which are otherwise difficult to form under normal conditions. A mathematical model is developed using standard transport equations to calculate the time for heating of hydrothermal reactor and computer simulation of the model was carried out in SOLIDWORKS& reg to validate it. The materials used to form reactor vessel were stainless steel (outer body) and TEFLON (PFA) (inner vessel). It was shown that composite wall, its geometry, construction & properties greatly affect the time and pattern of heat transfer. The time calculated and pattern generated were found to be in good agreement with experimental values.
Heat Transfer Equipment for Space Shuttle Orbiter, Its Main Engine (Aerojet Rocketdyne RS 25), Thermal (Passive and Active), Environmental Control and Life Support System
Publisher: MDPI AG
Date: 13-06-2022
DOI: 10.20944/PREPRINTS202206.0182.V1
Abstract: Space shuttle has been a hall mark of American space program since its inception. Despite its temporary shutdown few years ago, with the recent interest in space exploration which includes revitalizing human outpost in microgravity and transportation required to build it, realize other experiments (e.g. in space telescopes, in space manufacturing) and interplanetary voyages, it has regained attention. Its superior design, manufacturing, materials, performance, durability, and efficiency place it among the best, in fact, the only effort by mankind to build a reusable craft horizontally, launch vertically like a rocket and fly back like a plane. Various requirements emerge during its design (thermal, fluid, acoustics, vibration and structural) and design of its main engine (Aerojet Rocketdyne RS 25) which requires considerable attention, heat transfer being most important. This facilitated and necessitated use of various types of heat exchangers such as single coil, heat pipe, built in internal heat exchanger (IHEX), external heat exchanger (EHEX), condensing heat exchanger (CHEX), Interface heat exchangers (InHEX), regenerative heat exchanger (RHEX) and compact heat exchangers (CoHEX), change, manipulate and optimize their configurations in piping and instrumentation diagrams (PIDs). In this short narrative, an effort has been made to summarize them, and their developments over time with a focus on the application, design, manufacturing, materials, and performance (in service and final operation).
Pyrometallurgy and Electrometallurgy of Rare Earths – Part B: Cell design, construction, rate processes, and unit operation
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-10-2022
Detail design (DD) of non-tactical deployable 20 GWh (17.20841 kilo ton TNT) plane wave lens configuration fusion device
Publisher: Research Square Platform LLC
Date: 07-11-2022
DOI: 10.21203/RS.3.RS-2244327/V1
Abstract: A simple plane wave lens, using an inert central plastic wave shaper, has been designed. An experiment was done with a 4 in diam, zeroth order design. An iterative technique that uses measured time deviations to connect the next wave shape was developed. Two identical versions of the first iterated shape were fired. Arrival time deviations in these first iterates fell within 50 ns bonds. With greater care and further iterations, lenses bound by 10 ns deviations seem possible.
Detail design (DD), front end (FE), back end (BD) design of non-tactical deployable 20 GWh (17.20841 kilo ton TNT) plane wave lens configuration fusion device
Publisher: Research Square Platform LLC
Date: 09-11-2022
DOI: 10.21203/RS.3.RS-2244327/V2
Abstract: A simple plane wave lens, using an inert central plastic wave shaper, has been designed. An experiment was done with a 4 in diam, zeroth order design. An iterative technique that uses measured time deviations to connect the next wave shape was developed. Two identical versions of the first iterated shape were fired. Arrival time deviations in these first iterates fell within 50 ns bonds. With greater care and further iterations, lenses bound by 10 ns deviations seem possible. An advanced and novel integration method is applied. It is shown that this technique bears significant advantage over prior methods and is meritorious.
Related Organisations
National Aeronautics And Space Administration
Location: No location found
Massachusetts Institute Of Technology
Location: United States of America
National Aeronautics And Space Administration
Location: United States of America
Related Funding Activities
Flame Spray Processing Of Bioceramic (Calcium Phosphate) Coatings
Start Date: 2012
End Date: 2013
Funder: COMSATS Institute of Information Technology
View Funded Activity