6,611 research outputs found
Bibliographics for the 983 eprints in the live archives of E-LIS : trends and status report up to 7th July 2004, based on author-self-archiving metadata
No full textThe priority for ideas and philosophy related to "Network Theory" have been traced back and documented by Braun(2004),and credit goes to Karinthy(1929).The IT has empowered to realise it, as the most practical phenomena and it is no more a humour. The OAI (Open Archives Initiatives)and ACIS (Academic Contributor Information System)are progressive in the direction ,which may lead to realise the "Collective Genius" at global level. Focus of present study is on Author-Self-Archiving (A-S-A)Metadata of the 983 Eprints in the Live Archives of the E-LIS (EPrints of Library and Information Science),which were approved till 7th July 2004.The A-S-A Metadata was used for librametric analysis. Self-explanatory bibliographics are illustrated.The highlights include: Conference papers (34%); highest approval, June 2004 (28%); published archives (76%);not refereed (52%); not in public domain (60%); highest self-archiving-author (De Robbio, Antonella).The Nos. of EPrints having single JITA domain specifications were: Theoretical and general aspects of libraries and information(27); Information use and sociology of information(80);Users,literacy and reading(13);Libraries as physical collections(30);Publishing and legal issues(57);Management(13);Industry, profession and education(36);Information sources, supports, channels(113) ; Information treatment for information services, Information functions and techniques (101); Technical services libraries, archives and museums(25); Housing technologies(1); Information technology and library technology(92); and Inter-domainery (395) i.e. having specifications of two or more than two JITA classes
Determination of dynamic variations in the optical properties of graphene oxide in response to gas exposure based on thin-film interference
No full textWe present an effective yet simple approach to study the dynamic variations in optical properties (such as the refractive index (RI)) of graphene oxide (GO) when exposed to gases in the visible spectral region, using the thin-film interference method. The dynamic variations in the complex refractive index of GO in response to exposure to a gas is an important factor affecting the performance of GO-based gas sensors. In contrast to the conventional ellipsometry, this method alleviates the need of selecting a dispersion model from among a list of model choices, which is limiting if an applicable model is not known a priori. In addition, the method used is computationally simpler, and does not need to employ any functional approximations. Further advantage over ellipsometry is that no bulky optics is required, and as a result it can be easily integrated into the sensing system, thereby allowing the reliable, simple, and dynamic evaluation of the optical performance of any GO-based gas sensor. In addition, the derived values of the dynamically changing RI values of the GO layer obtained from the method we have employed are corroborated by comparing with the values obtained from ellipsometry.This article is published as Tabassum, Shawana, Liang Dong, and Ratnesh Kumar. "Determination of dynamic variations in the optical properties of graphene oxide in response to gas exposure based on thin-film interference." Optics Express 26, no. 5 (2018): 6331-6344. DOI: 10.1364/OE.26.006331. Posted with permission.</p
Development of Wire and Arc Additive Manufacturing Process for Deposition of Ni- Based Super Alloy
No full textWire Arc Additive Manufacturing (WAAM) is an innovative form of 3D printing that uses an electric arc as a heat source to melt metal wire, which is then deposited layer by layer to create complex metal parts. This technique achieves high deposition rates and allows the building of large-scale components with significant cost and material savings compared to traditional manufacturing methods. In the past, a variety of materials have been fabricated through WAAM. However, very little work has been done using WAAM on nickel-based super-alloys. Nickel-based super-alloys are a class of metallic alloys known for their exceptional high-temperature strength, resistance to creep deformation, and resistance to corrosion and oxidation. The excellent combination of these properties makes these materials ideal for use in jet engines, gas turbines, power plants, and other high-temperature applications. Manufacturing these complex design components of nickel-based superalloys using traditional methods is challenging and expensive. To address this issue, the current research focuses on the feasibility and development of the WAAM process as a promising alternative for producing nickel-based components.
The initial focus is on establishing a robust GMAW-based WAAM process. This involves optimizing the gas metal arc welding (GMAW) process parameters, a key element of WAAM. Through numerous trials, the main aim is to identify the ideal settings for factors such as current, voltage, and welding speed. This study uses a bi-directional, low-cost, GMAW-based wire arc additive manufacturing (WAAM) setup to deposit aerospace-grade super-alloy IN718. Orthogonally designed experiments are carried out to optimize process parameters for single and multilayer bead geometries.
Additionally, ANOVA analysis and S/N ratio plots are employed to optimize process parameters for bead characteristics such as width, reinforcement, penetration, dilution, WRFF, WPSF, surface waviness, and effective area. Furthermore, the effect of heat input is discussed. The study results indicate that increased heat input increases bead parameters like bead width, reinforcement, dilution, penetration, and weld form factor while negatively impacting the weld shape factor and wetting angle.
After optimizing process parameters, characterizations of WAAM-deposited materials were done based on metallurgical and mechanical testing. The metallurgical analysis includes optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). The mechanical analyses were done based on hardness and tensile testing. These tests provide insights into the microstructure, phases present, elemental composition, grain orientation, and material strength.
The microstructural examination reveals that a high heat input produces a coarse grain structure with an average grain size of 72.29 µm. In contrast, a low heat input produces a finer grain structure with an average grain size of 32.12 µm and smaller Laves phases. The XRD analysis shows the presence of NbC and TiC phases in the low heat input sample, enhancing the deposited material's mechanical properties. The multilayer wall structures fabricated with high heat input demonstrate more uniformity in shape and less waviness than those fabricated with low heat input. Tensile testing results indicate that the low heat input sample exhibits higher strength (775.82 MPa) than the high heat input sample (741.07 MPa). This increased strength is attributed to the smaller grain structure and higher hardness (278.11 HV) observed in the low heat input sample compared to the high heat input sample (257.26 HV). The EBSD analysis further confirms that the low heat input sample has a highly textured surface, more grain boundary lengths, and larger grain boundary orientation, which contributes to its superior mechanical properties.
This study also provides insights into cooling environments and thermal management techniques for WAAM of IN718 components. The material was deposited under four different heat-input conditions, using either air or water cooling. The layers were deposited in a normal atmospheric environment with air cooling, while water cooling involved depositing the material inside a water tank with varying water levels. To validate the air- and water-cooling thermal management techniques, IN718 single-pass, and multilayer linear walls were deposited under four different heat-input conditions. Temperature profiles were recorded during single-layer depositions, and geometric and microstructural features were examined. The SEM analysis revealed that the microstructure in the building direction was non-homogeneous compared to that in the deposition direction.
Additionally, water cooling significantly influenced bead characteristics, such as wall width and height. The grain size and anisotropy of the mechanical properties decreased with water cooling. Therefore, water cooling is economical and efficient in mitigating excessive heat accumulation in WAAM-deposited IN718 components.
Further, this study also examines the effects of shielding gases at various heat inputs on the bead geometry, microstructure evolution, and mechanical properties of Inconel 718 deposited by WAAM. Bead-on-plate experiments were conducted with the CMT technique of GMAW, utilizing Taguchi’s L9 orthogonal array. The factor effects, their contributions, and optimal levels were analyzed using ANOVA and S/N ratio approaches. To determine heat input, the dynamic characteristics of the welding power source were recorded and processed.
The study found increased heat input led to more pronounced bead geometry characteristics and a wider heat-affected zone (HAZ). Increasing the CO2 concentration in the Ar + CO2 mixture altered the weld texture from silver metallic (with pure Ar) to grey with 2.5% CO2 and light yellow with 20% CO2. Higher bead width, reinforcement, penetration, and dilution were observed with an Ar 20% CO2 mix. Beads formed with 2.5% CO2 were continuous and smoother at all heat inputs. Welds prepared in a 100% Ar shielding environment exhibited higher hardness than those with 2.5% CO2 and 20% CO2 mixtures. Higher concentrations of Nb-rich precipitates, identified through SEM-EDS analysis, contributed to increased strength.
Finally, the project culminated in a comparative analysis of two WAAM variants: CMT-WAAM and GMAW-WAAM. CMT-WAAM provides a more controllable arc with lower spatter, potentially reducing porosity and improving bead geometry. A comparison of surface waviness and mechanical properties shows that waviness is lower, whereas strength is higher in CMT WAAM components. Understanding these distinctions empowers us to decide the most suitable WAAM approach for specific applications
A Unified Shell model for Buoyancy-Driven Turbulence
No full textWe construct a unified shell model for stably stratified and convective turbulence. Shell model simulation of stably stratified flow in turbulent regime exhibit Bolgiano-Obukhbov (BO) scaling in which the kinetic energy spectrum varies as . However, simulation of convective turbulence shows Kolmogorov's spectrum. These results are consistent with the direct numerical simulations of Kumar {\em et al.} [Phys. Rev. E {\bf 90}, 023016 (2014)]. We also observe a dual scaling ( and ) for a limited range of parameters in stably stratified flow
Foaming of Friction Stir Processed Al Precursor by Microwave Heating
No full textA substance with pores (voids) is known as a porous medium or material. The skeleton element of the substance is frequently referred to as the "matrix" or "frame." Many naturally occurring materials, including rocks and soil (such as aquifers and petroleum reservoirs), zeolites, biological tissues (such as bones, wood, and cork), and man-made materials, including metal, cement, ceramics, and polymers, can be categorized as porous media. These cellular materials are typically utilized in cases where weight needs to be reduced. Metals have a high energy absorption capacity during deformation caused by dislocation motion. As a result, metallic foams might offer an engineering material with the beneficial mechanical characteristics of polymeric foams, making them useful in applications where higher yield stresses and energy absorption are required. For many years, material scientists and technologists have worked to develop porous metals and metal foams. Metal foam is mainly composed of liquid and solid phases that coexist in a specific structure. A gas source is utilized to introduce pores into the structure. This gas source could be a blowing agent powder added to a liquid metal at a specific temperature, direct gas bubbles introduced to a liquid metal, or a blowing agent powder imbedded in the metal that expands when heated.
In the current technique, Titanium Hydride (TiH2: blowing agent), Aluminum powder (Al powder) and Calcium Carbonate (CaCO3: stabilizing agent) is embedded in the Aluminum AA7075 and AA6063 matrix using Friction Stir Processing (FSP) as the starting procedure. At this point, the metal is referred to as a precursor. This precursor creates a porous structure after being heated in a furnace/microwave at a specific time and temperature for the decomposition of the TiH2. As a result of this decomposition, hydrogen gas is released, which remains in the matrix and forms pores. Metal foam is created when these holes have a spherical shape or a design that causes the density to be significantly reduced.
The results of various experiments such as powder filling techniques, tool pin profiles, and a new precursor development technique called as Friction Stir Deposition (FSD) are reported in this research work in order to ensure uniform TiH2 distribution throughout the aluminum matrix for producing closed cell aluminum metal foam and its characterization. This indirect foaming method prevents the early melting of the material. This procedure opens the way for the creation of effective localized foam parts.
Based on the characteristic of the developed foam, it has been observed that the distribution of foamable mixture improved in the buried hole technique by creating an entrapped space to restrict the mixture to flow away and produce a porous Aluminum with a porosity of approximately 81% at 4-passes with 40% TiH2 composition. As the number of FSP passes increases, pore size decreases. The percentage decrease in pore size from one pass to four passes during microwave heating is observed as 17.78 % as compared to 14.76 % in furnace heating. The time required for the development of foam in microwave heating is lower than that of furnace heating and the time needed for the development of foam in microwave heating is only 16.67% of the furnace heating. It is also observed from the results that the porosity in sandwich and groove techniques is 69% and 48%, respectively. The buried hole technique has higher porosity and improvement in porosity is of 17.92% and 71.25% as compared to sandwich and groove techniques, respectively.
It is also observed that during different tool pin profiles, the distribution of the foaming mixture improves with continuous material deformation by straight threaded cylindrical (STC) tool pin compared to the pulsating effect produced by square (SQ) and triangular (TR) pin. The foam developed at straight threaded cylindrical (STC) pin shows uniform deformation behavior during compression test than the foam developed by other tool profiles.
The foam developed by friction stir deposition (FSD) technique shows uniform distribution of foaming powder in 4 and 5 numbers of holes in the consumable rod as compare to other. The hardness of the deposited precursor is lower than the base metal. The deposited material shows equiaxed fine grains that occurred due to dynamic recrystallization during deposition also have longer plateau stress due to optimum pore size which absorbs energy for longer duration
Story of the Story-Teller: A Conversation with Ramendra Kumar
No full textRamendra Kumar (Ramen) is an award-winning writer, storyteller and inspirational speaker with 42 books to his name. Ramen’s writings have been published by many of the leading publishers in the county and translated into 30 languages. They have found a place in several textbooks and anthologies. He has written across all genres ranging from picture books to adult fiction, satire, poetry, travelogues, biographies and on issues related to parenting and relationships. He has been invited to literary festivals held in Denmark, Greece, Sharjah, Sri Lanka as well Indian events including the prestigious Jaipur Litfest to conduct storytelling sessions and creative writing workshops. He has also been empanelled by Pearson India Education Services as well as several schools to conduct workshops. He was nominated as a Jury Member for the Best Children’s Author Category of The Times of India’s ‘Women AutHer’ Awards 2020. Many of his stories have been showcased by popular audio streaming, apps both within and outside the country, such as Spotify, Gaatha, Talking Stories Radio – London et al.
An Engineer & an MBA, Ramen was serving as the General Manager (Corporate Communications), SAIL, Rourkela Steel Plant, when he took Voluntary Retirement to pursue his passion, in August 2020. To know more about the writer, you can visit his website www.ramendra.in & his page on Wikipedia. Dr. Sagar Kumar Sharma interviews the author and unfolds the pages of his life.
 
NOTICE!!! This person (known as Ashwin Kumar) plagiarized the text titled: "Using phenomenological research methods in qualitative health research"
No full textEDITORIAL NOTICE:
1. This publication has been removed due to detected plagiarism by the editorial.
2. If you have cited, you MUST UPDATE your reference with the following original article:
Wojnar, Danuta, and Kristen Swanson. “Phenomenology An Exploration”. Journal of holistic nursing : official journal of the American Holistic Nurses’ Association 25 (01 October 2007): 172-80; discussion 181. https://doi.org/10.1177/0898010106295172.
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3. Submitter's Profile Record (the thief, the plagiariser):
Name: Ashwin KumarURL: http://www.freewebs.com/ak2146Affiliation: University of Western Sydney, Australia.Country: AustraliaBio Statement:Dr. Ashwin Kumar,PO Box 571,Toongabbie,Sydney,Australia, NSW, 2146.Homepage: http://www.freewebs.com/ak2146Email: [email protected]
[email protected]: 0432-622-147Skype Internet Phone ID: ak2146
Dr. Ashwin Kumar (BA, MA (Distinction), PhD) is an academic researcher whose research interests and areas of expertise include: Complementary and alternative medicine (CAM), ageing and social gerontology, sociology, social anthropology, sociology of care, public health, health promotion, Indigenous health, migrant and refugee health, disability and chronic illness. Ashwin is the author of 8 books and numerous academic journal articles in the field of public health, health sociology and anthropology of health and illness. His books: The Lived Experience of Caring; The Lived Experience of Ageing; The Lived Experience of Using Complementary and Alternative Medicine; Doing Sociology; The Basics of Sociology; Plain English Writing; Research and Writing Skills and Writing Effective Essays are available at:
http://www.amazon.com/s/ref=ntt_athr_dp_sr_1?_encoding=UTF8&sort=relevancerank&search-alias=books&field-author=PhD.%20Ashwin%20Kumar
My homepage: http://www.freewebs.com/ak2146
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Special Issue on Recent Advances in Petri Nets, Automata, and Discrete-Event Hybrid Systems
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Multivariate Quantitative Representativeness and Constituency Analysis of Ecological Observation Networks
No full textCite this code as: Kumar, J. (2023). Multivariate Quantitative Representativeness and Constituency Analysis of Ecological Observation Networks (Version 1.0) [Computer software]. https://doi.org/10.5281/zenodo.8048530
Multivariate Quantitative Representativeness and Constituency Analysis of Ecological Observation Networks
Author: Jitendra (Jitu) Kumar ([email protected]), Oak Ridge National Laboratory
Regional and global ecological research networks, representing coordinated and standardized as well as adhoc networks of observation sites, provide valuable observations necessary for ecological modeling and synthesis studies. Studies conducted across observational networks strive to scale up their results to larger areas, trying to reach conclusions that are valid throughout regional, continental, and even global scales. Network representativeness and constituency can show how well conditions at those locations represent conditions elsewhere within a larger area containing the network and can be used to help scale-up results over larger regions.
Representativeness: Euclidean distance between two sites plotted in multivariate environmental space can be used as an inverse measure of multivariate similarity to quantify representativeness. Close sites in environmental space have a similar combination of environmental factors, and therefore are highly representative of each other.
Constituency: For any site in the network, its Constituency represent all locations that are best represented by the multivariate environmental drivers at that site.
Code Compilation:
make
Edit the ```makefile``` as needed for your platform.
CC=gcc
CFLAGS= -O3
hpea: network_representativeness.o\
utility.o
(CFLAGS) *.o -lm -o network_representativeness
.o:
(CFLAGS) -c $<
clean:
\rm *.o network_representativeness
Running the representativeness analysis:
Usage: network_representativeness -infile input data file [ASCII]
-coordsfile coordinate file name
-clustfile coordinate file name [OPTIONAL -- must be used with -siteclustfile]
-sitefile site data file name
-siteclustfile site data file name [OPTIONAL -- must be used with -clustfile]
-nsites No. of sites
-minmaxfile minmax file name
-outfile output file name
-nrows No. of rows in input data
-ncols No. of variables
-details [OPTIONAL -- turn on output representativeness for each site, default is to write network representativeness and constituency only.]
-help program usage help.
Publications using ```network_reprentativeness``` code:
Kumar, J., Coffin, A. W., Baffaut, C., Ponce-Campos, G., Witthaus, L., and Hargrove, W. W. (2023) "Quantitative Representativeness and Constituency of the Long-Term Agroecosystem Research Network, and Analysis of Complementarity with Other Existing Ecological Networks", Environmental Management (in press)
M. M. T. A. Pallandt, J. Kumar, M. Mauritz, E. A. G. Schuur, A.-M. Virkkala, G. Celis, F. M. Hoffman, and M. Göckede. Representativeness assessment of the pan-arctic eddy covariance site network and optimized future enhancements. Biogeosciences, 19(3):559--583, 2022. https://doi.org/10.5194/bg-19-559-2022
J. Kumar, F. M. Hoffman, W. W. Hargrove, and N. Collier. Understanding the representativeness of FLUXNET for upscaling carbon flux from eddy covariance measurements. Earth System Science Data Discussion, 2016:1--25, August 2016. https://doi.org/10.5194/essd-2016-36.If you use this software, please cite it as below.
Kumar, J. (2023). Multivariate Quantitative Representativeness and Constituency Analysis of Ecological Observation Networks (Version 1.0) [Computer software]. https://doi.org/10.5281/zenodo.804853
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