79 research outputs found
Predictive Analysis of Facebook using WEKA
Web-based social networks have become more prevalent as a medium for connecting like-minded people. The public accessibility of such social networks with the capability to share information, thoughts, opinions, and experience offers great potential to mankind and organizations. Social network has gained amazing attention in the last decade. Accessing social network sites such as Facebook, Google+, Twitter and LinkedIn through the internet and the web 2.0 technologies has become more affordable. Facebook is social networking service on which after registering on the the site, users can create their profile, add other users as friends, interchange messages, post status updates, photos, and share videos etc. People are more interested in and relying on Facebook for information, news and opinion of other users on various subject matters. Based on the data available for the facebook, the number of profiles has increasing expressively but with the fast growth of users, fake profiles/users have also grown. The WEKA data mining tool was used by performing adjustments of the attributes in order to come up with a decisive output. This paper presents the comprehensive review of social network and the trustworthiness of social networks
Mapping the Geography of Sustainability Transitions Research: A Bibliometric Analysis
The transition towards sustainability is a global challenge, and in recent decades, Sustainability Transitions (ST) research has emerged as a promising approach to address climate change-led uncertainty. Despite the rapid rise in the sustainability transitions literature, it is primarily focused on developed or global north countries. The present paper attempts to use bibliometric tools to comprehend the intellectual landscape and distribution between global north-south and analyse the trends and hotspots in global south countries. The paper comprehensively examined ST literature on the Scopus citation database (from the inception of ST in 1994 to December 31, 2020). Based on statistical analysis performed on the dataset, there has been an exponential rise in research publications on ST since 2012. Globally, ST researchers mainly belong to OECD countries from Western Europe, especially in the UK, Netherlands and Germany. Conversely, the global south is lagging, except few developing nations such as China, South Africa, Brazil, and India. This skewed representation reflects the higher prevalence of ST initiatives in the global north, predominantly by a few European countries. About 40% of ST research is published in journals from the UK, Netherlands, the U.S., Switzerland and Canada. The citation analysis reflects that 60% of citations are from British and Dutch scholars, indicating a low academic influence of ST authors from developing countries. This study would stimulate more interest among Global South academics and policy researchers to put more effort into ST research and publication to bridge the existing gap
Sonochemical synthesis of Gd3+ doped CoFe2O4 spinel ferrite nanoparticles and its physical properties
In this work, a facile and green method for gadolinium doped cobalt ferrite (CoFe2−xGdxO4; x = 0.00, 0.05, 0.10, 0.15, 0.20) nanoparticles by using ultrasonic irradiation was reported. The impact of Gd3+ substitution on the structural, magnetic, dielectric and electrical properties of cobalt ferrite nanoparticles was evaluated. The sonochemically synthesized spinel ferrite nanoparticles were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). X-ray diffraction (XRD) study confirmed the formation of single phase spinel ferrite of CoFe2−xGdxO4 nanoparticles. XRD results also revealed that ultrasonic irradiation seems to be favourable to achieve highly crystalline single crystal phase gadolinium doped cobalt ferrite nanoparticles without any post annealing process. Fourier Transform Infrared and Raman Spectra confirmed the formation of spinel ferrite crystal structure. X-ray photoelectron spectroscopy revealed the impact of Gd3+ substitution in CoFe2O4 nanoparticles on cation distribution at the tetrahedral and octahedral site in spinel ferrite crystal system. The electrical properties showed that the Gd3+ doped cobalt ferrite (CoFe2−xGdxO4; x = 0.20) exhibit enhanced dielectric constant (277 at 100 Hz) and ac conductivity (20.2 × 10−9 S/cm at 100 Hz). The modulus spectroscopy demonstrated the impact of Gd3+ substitution in cobalt ferrite nanoparticles on grain boundary relaxation time, capacitance and resistance. Magnetic property measurement revealed that the coercivity decreases with Gd3+ substitution from 234.32 Oe (x = 0.00) to 12.60 Oe (x = 0.05) and further increases from 12.60 Oe (x = 0.05) to 68.62 Oe (x = 0.20). Moreover, saturation magnetization decreases with Gd3+ substitution from 40.19 emu/g (x = 0.00) to 21.58 emu/g (x = 0.20). This work demonstrates that the grain size and cation distribution in Gd3+ doped cobalt ferrite nanoparticles synthesized by sonochemical method, is effective in controlling the structural, magnetic, and electrical properties, and can be find very promising applications. © 2017 Elsevier B.V.Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504
Polypropylene nanocomposite filled with spinel ferrite NiFe 2 O 4 nanoparticles and in-situ thermally-reduced graphene oxide for electromagnetic interference shielding application
Herein, we presented electromagnetic interference shielding characteristics of NiFe2O4 nanoparticles-in-situ thermally-reduced graphene oxide (RGO)-polypropylene nanocomposites with the variation of reduced graphene oxide content. The structural, morphological, magnetic, and electromagnetic parameters and mechanical characteristics of fabricated nanocomposites were investigated and studied in detail. The controllable composition of NiFe 2 O 4 -RGO-Polypropylene nanocomposites exhibited electromagnetic interference (EMI) shielding effectiveness (SE) with a value of 29.4 dB at a thickness of 2 mm. The enhanced EMI shielding properties of nanocomposites with the increase of RGO content could be assigned to enhanced attenuation ability, high conductivity, dipole and interfacial polarization, eddy current loss, and natural resonance. The fabricated lightweight NiFe 2 O 4 -RGO-Polypropylene nanocomposites have potential as a high performance electromagnetic interference shielding nanocomposite. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504, IGA/CPS/2019/007]; Tomas Bata University in Zlin, Czech Republi
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CuxCo1-xFe2O4 (x = 0.33, 0.67, 1) Spinel Ferrite Nanoparticles Based Thermoplastic Polyurethane Nanocomposites with Reduced Graphene Oxide for Highly Efficient Electromagnetic Interference Shielding
CuxCo1-x Fe2O4 (x = 0.33,0.67,1)-reduced graphene oxide (rGO)-thermoplastic polyurethane (TPU) nanocomposites exhibiting highly efficient electromagnetic interference (EMI) shielding were prepared by a melt-mixing approach using a microcompounder. Spinel ferrite Cu0.33Co0.67Fe2O4 (Cu-CoF1), Cu0.67Co0.33Fe2O4 (CuCoF2) and CuFe2O4 (CuF3) nanoparticles were synthesized using the sonochemical method. The CuCoF1 and CuCoF2 exhibited typical ferromagnetic features, whereas CuF3 displayed superparamagnetic characteristics. The maximum value of EMI total shielding effectiveness (SEt) was noticed to be 42.9 dB, 46.2 dB, and 58.8 dB for CuCoF1-rGO-TPU, CuCoF2-rGO-TPU, and CuF3-rGO-TPU nanocomposites, respectively, at a thickness of 1 mm. The highly efficient EMI shielding performance was attributed to the good impedance matching, conductive, dielectric, and magnetic loss. The demonstrated nanocomposites are promising candidates for a lightweight, flexible, and highly efficient EMI shielding material
Lightweight, flexible and high-performance nanocomposites based on reduced graphene oxide and spinel ferrite (ZnFe2O4 / CoFe2O4) nanoparticles in thermoplastic polyurethane matrix for electromagnetic interference shielding applications
Lightweight and flexible material with enhanced electromagnetic interference shielding effectiveness is highly in demand in the electronics and communication industry. Herein, we synthesized CoFe2O4 and ZnFe2O4 nanoparticles using the sonochemical method, and further, these nanoparticles were embedded inside thermoplastic polyurethane (TPU) along with reduced graphene oxide (rGO) by a melt-mixing approach using a microcompounder. CoFe2O4 or ZnFe2O4 nanocomposites in the TPU matrix with rGO showed outstanding electromagnetic shielding performance having a constant thickness of 0.80 mm, only. The maximum total shielding effectiveness (SET) was 48.3 dB for ZnFe2O4 nanocomposite and 50.76 dB for CoFe2O4 nanocomposite. These results indicate that the developed nanocomposite can be potentially utilized for electromagnetic shielding applications. © 2021 NANOCON Conference Proceedings - International Conference on Nanomaterials. All rights reserved.Grantová Agentura České Republiky, GA ČR; Univerzita Tomáše Bati ve Zlíně; Leibniz-Institut für Polymerforschung Dresden, IP
Innovative investigation of zinc oxide nanoparticles used in dentistry
Dental caries is a major lifestyle concern as dental components affect the face of an individual. The issue of tooth decay occurs in every age group throughout the globe. Researchers are probing incipient implements and techniques to develop filling agents for decayed teeth. Zinc oxide (ZnO) powder is utilized mostly as a filling agent. Nanotechnology enhanced the efficiency of compounds of metal oxides utilized for dental caries. The present study aims to investigate the properties of ZnO nanoparticles (NPs) synthesized chemically (using ZnCl2 and NaOH) as well as biologically (using aqueous leaf extract of Murraya paniculata). The XRD patterns confirm that ZnO NPs have a hexagonal crystalline structure with particle sizes of 47 nm and 55 nm for chemically and biologically synthesized NPs, respectively. The FE-SEM data confirm the nanorod and spherical/cubical shape morphologies for the chemically and biologically synthesized ZnO NPs, respectively. FTIR data show the peaks between 4000 and 450 cm(-1) of the functional groups of -OH, C-O, -C-H-, and Zn-O bonds. The UV-Vis absorption study indicates a peak around 370 nm and a hump around 360 nm corresponding to the chemically and biologically synthesized ZnO NPs, respectively. An antibacterial bioassay was performed and compared with commercially available ZnO bulk powder against tooth decaying pathogens, viz., Streptococcus mutans, Staphylococcus aureus, E. coli, and Lactobacillus fermentum, and found that both ZnO NPs had results closer to those of the standard drug (rifampicin). Thus, the synthesized ZnO NPs may be utilized as nano-drugs for the application of tooth decaying filling agents. Even biologically synthesized ZnO NPs may be considered more environmentally friendly and less toxic to human health concerns.UGC, New DelhiUniversity Grants Commission, UGC; University of Lucknow, L
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High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution
The development of flexible, lightweight, and thin high-performance electromagnetic interference shielding materials is urgently needed for the protection of humans, the environment, and electronic devices against electromagnetic radiation. To achieve this, the spinel ferrite nanoparticles CoFe2O4 (CZ1), Co0.67Zn0.33Fe2O4 (CZ2), and Co0.33Zn0.67Fe2O4 (CZ3) were prepared by the sonochemical synthesis method. Further, these prepared spinel ferrite nanoparticles and reduced graphene oxide (rGO) were embedded in a thermoplastic polyurethane (TPU) matrix. The maximum electromagnetic interference (EMI) total shielding effectiveness (SET) values in the frequency range 8.2-12.4 GHz of these nanocomposites with a thickness of only 0.8 mm were 48.3, 61.8, and 67.8 dB for CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU, respectively. The high-performance electromagnetic interference shielding characteristics of the CZ3-rGO-TPU nanocomposite stem from dipole and interfacial polarization, conduction loss, multiple scattering, eddy current effect, natural resonance, high attenuation constant, and impedance matching. The optimized CZ3-rGO-TPU nanocomposite can be a potential candidate as a lightweight, flexible, thin, and high-performance electromagnetic interference shielding material
Impact of grain size and structural changes on magnetic, dielectric, electrical, impedance and modulus spectroscopic characteristics of CoFe2O4nanoparticles synthesized by honey mediated sol-gel combustion method
In this work CoFe2O4spinel ferrite nanoparticles were synthesized by honey mediated sol-gel combustion method and further annealed at higher temperature 500 °C, 700 °C, 900 °C and 1100 °C. The synthesized spinel ferrite nanoparticles is investigated by x-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), field emission scanning electron microscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometer. The x-ray diffraction study reveals face-centered cubic spinel cobalt ferrite crystal phase formation. The crystallite size and lattice parameter are increased with annealing temperature. Raman and Fourier transform infrared spectra also confirm spinel ferrite crystal structure of synthesized nanoparticles. The existence of cation at octahedral and tetrahedral site in cobalt ferrite nanoparticles is confirmed by x-ray photoelectron spectroscopy. Magnetic measurement shows increased saturation magnetization 74.4 emu g-1at higher annealing temperature 1100 °C, high coercivity 1347.3 Oe at lower annealing temperature 500 °C, and high remanent magnetization 32.3 emu g-1at 900 °C annealing temperature. The magnetic properties of synthesized ferrite nanoparticles can be tuned by adjusting sizes through annealing temperature. Furthermore, the dielectric constant and ac conductivity shows variation with frequency (1-107Hz), grain size and cation redistribution. The modulus spectroscopy study reveals the role of bulk grain and grain boundary towards the resistance and capacitance. The cole-cole plots in modulus formalism also well support the electrical response of nanoparticles originated from both grain and grain boundaries. The dielectric, electrical, magnetic, impedance and modulus spectroscopic characteristics of synthesized CoFe2O4spinel ferrite nanoparticles demonstrate the applicability of these nanoparticles for magnetic recording, memory devices and for microwave applications. © 2017 Vietnam Academy of Science & Technology.LO1504, NPU, Northwestern Polytechnical Universit
Impact of sonochemical synthesis condition on the structural and physical properties of MnFe2O4 spinel ferrite nanoparticles
Herein, we report sonochemical synthesis of MnFe2O4 spinel ferrite nanoparticles using UZ SONOPULS HD 2070 Ultrasonic homogenizer (frequency: 20 kHz and power: 70 W). The sonication time and percentage amplitude of ultrasonic power input cause appreciable changes in the structural, cation distribution and physical properties of MnFe2O4 nanoparticles. The average crystallite size of synthesized MnFe2O4 nanoparticles was increased with increase of sonication time and percentage amplitude of ultrasonic power input. The occupational formula by Xray photoelectron spectroscopy for prepared spinel ferrite nanoparticles was (Mn0.29Fe0.42[Mn0.71Fe1.58]O-4 and (Mn0.28Fe0.54) [Mn0.72Fe1.46]O-4 at sonication time 20 min and 80 min, respectively. The value of the saturation magnetization was increased from 1.9 emu/g to 52.5 emu/g with increase of sonication time 20 min to 80 min at constant 50% amplitude of ultrasonic power input, whereas, it was increased from 30.2 emu/g to 59.4 emu/g with increase of the percentage amplitude of ultrasonic power input at constant sonication time 60 min. The highest value of dielectric constant (epsilon') was 499 at 1 kHz for nanoparticles at sonication time 20 min, whereas, ac conductivity was 368 x 10(-9) S/cm at 1 kHz for spinel ferrite nanoparticles at sonication time 20 min. The demonstrated controllable physical characteristics over sonication time and percentage amplitude of ultrasonic power input are a key step to design spinel ferrite material of desired properties for specific application. The investigation of microwave operating frequency suggest that these prepared spinel ferrite nanoparticles are potential candidate for fabrication of devices at high frequency applications
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