A Comparative Study of Induced-Arc and Resistive Welds Employing SEM and X-Ray Emission Studies

1972 ◽  
Vol 30 ◽  
pp. 490-491
Author(s):  
Arthur J. Saffir ◽  
Donald I. Zenobia
Keyword(s):  
Arc Welding ◽  
Biomedical Applications ◽  
Copper Substrate ◽  
Precious Metals ◽  
Electrical Contacts ◽  
X Ray ◽  
Relative Potential ◽  
Physical And Chemical ◽  
Emission Studies ◽  
A Current

The purpose of this study was to evaluate the two techniques that are commercially used to bond the components of composite electrical contacts. These materials, usually consisting of a precious metal contacting region bonded to a copper substrate, offer substantial economy compared to similar devices made entirely from precious metals. They also possess unique desirable properties useful in other electronic and biomedical applications. However, these advantages can only be realized if the weld can withstand the severe physical and chemical environment in which it must operate.The resistive welds are created by bringing the components into contact and then providing a current in order to create sufficient heat for welding. Induced-arc welding requires more operations: the components are held apart with a relative potential of 10 to 100 volts; then they come into contact very briefly, 50 to 500 μsec; they are immediately drawn apart, striking an arc; finally, after arcing from 300 to 3000 μsec, they are forced together percussively while the current continues to flow.

Characterization of polyherbal-incorporated polycaprolactone nanofibrous mat for biomedical applications

2019 ◽  
Vol 34 (4-5) ◽  
pp. 401-411
Author(s):  
Rajalakshmi Ramamoorthy ◽  
Muthumanickkam Andiappan ◽  
Murugesan Muthalagu
Keyword(s):  
Drug Release ◽  
Biomedical Applications ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
Drug Release Rate ◽  
Electrospinning Technique ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Physical And Chemical

The polyherbal-loaded polycaprolactone nanofibrous mat was prepared by electrospinning technique, and physical and chemical characteristics of nanofibrous mats were studied using scanning electron microscopy, x-ray diffraction, thermogravimetric analyzer, and Fourier transform infrared spectroscopy. The presence of various phytochemicals in the crude monoherbal and polyherbal extracts was analyzed. The antimicrobial activity and biocompatibility of the polyherbal-loaded nanofibrous mats were studied. The drug release pattern of the polyherbal-loaded nanofibrous mats was studied at different time intervals. The 5% drug-loaded nanofibrous mat shows higher sustainable drug release rate than 1% and 3% drug-loaded nanofibrous mats. The cell viability was found to be 98.91%, 98.77%, 98.5%, and 98.22% for polycaprolactone and 1%, 3%, and 5% for polyherbal-loaded nanofibrous mats, respectively.

scholarly journals Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 92
Author(s):  
Jadranka Milikić ◽  
Aldona Balčiūnaitė ◽  
Zita Sukackienė ◽  
Dušan Mladenović ◽  
Diogo M. F. Santos ◽  
...  
Keyword(s):  
Current Density ◽  
Potassium Hydroxide ◽  
Electroless Deposition ◽  
High Efficiency ◽  
Low Cost ◽  
Copper Substrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Current ◽  
Scanning Electron

Bimetallic cobalt (Co)-based coatings were prepared by a facile, fast, and low-cost electroless deposition on a copper substrate (CoFe, CoMn, CoMo) and characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Prepared coatings were thoroughly examined for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution (1 M potassium hydroxide, KOH) and their activity compared to that of Co and Ni coatings. All five coatings showed activity for both reactions, where CoMo and Co showed the highest activity for HER and OER, respectively. Namely, the highest HER current density was recorded at CoMo coating with low overpotential (61 mV) to reach a current density of 10 mA·cm−2. The highest OER current density was recorded at Co coating with a low Tafel slope of 60 mV·dec−1. Furthermore, these coatings proved to be stable under HER and OER polarization conditions.

scholarly journals Properties and Structure of Nanocrystalline Layers Obtained by Manual Metal Arc Welding (MMA)

2017 ◽  
Vol 62 (3) ◽  
pp. 1479-1484 ◽  
Author(s):  
J. Górka ◽  
A. Czupryński ◽  
M. Adamiak
Keyword(s):  
Arc Welding ◽  
Composition Analysis ◽  
Resistant Steel ◽  
Metallographic Examination ◽  
X Ray ◽  
Metal Arc Welding ◽  
Chemical Composition Analysis ◽  
Iron Based ◽  
Interpass Temperature ◽  
A Current

AbstractThe present paper is the result of the investigations of the properties and structure of nanocrystalline layers deposited from iron-based nanoalloy on steel S355N substrate by manual metal arc welding method (MMA). In the process of welding a 100 A current intensity was used with desiccation preheating at 80°C while maintaining the interpass temperature at range of 200°C. The resultant deposit welds were subjected to macro and microscopic metallographic examination, X-ray phase analyses and crystallite size was analyzed by X-ray diffractometry (XRD), additionally EDX chemical composition analysis of precipitates during scanning electron microscopy was performed. Working properties of the obtained nanocrystalline deposit welds were evaluated based on hardness and metal-to-mineral abrasive wear. The results of the deposit welds working properties measurements were compared with the properties of wear resistant steel HARDOX 400 type used as the reference material.

scholarly journals EVALUATION OF COATINGS TENDENCY TO THE PORES AND NON-METAL INCLUSIONS FORMATION IN A WELD

2020 ◽  
Vol 5 (9) ◽  
pp. 67-80
Author(s):  
L. Zhabrev ◽  
S. Chuppina ◽  
A. Shamshurin ◽  
E. Lebedeva ◽  
O. Panchenko
Keyword(s):  
Arc Welding ◽  
Polyvinyl Butyral ◽  
Chemical Transformations ◽  
X Ray ◽  
Welding Steel ◽  
Restoration Work ◽  
Electric Arc Welding ◽  
Physical And Chemical ◽  
Metal Spraying ◽  
Common Defect

The task of welding steel elements painted with various coatings is found in a number of industries at the stages of factory assembly and installation of large-sized structures, as well as during repair and restoration work. The porosity of the welded metal is the most common defect in electric arc welding without removing the coating, and the tendency to pore formation is a normalized parameter in the certification of interoperable primers (EN ISO 17652-2: 2003). The studies carried out cover wide-spread polyacrylate, alkyd, epoxy, polyvinyl butyral primers in an extended working thicknesses range. In addition, the evaluation technique is used for zinc-filled and organosilicate protective coat-ings. Based on the study of the nonmetallic inclusions composition in a weld by energy dispersive X-ray spectroscopy and using a scanning electron microscope, the behavior features of the coatings de-struction products and their derivatives during physical and chemical transformations under welding are described. The technological features of welding without coating removing are noted: stability of the mode parameters, resistance to metal spraying and coating burnout activity in the areas adjacent to a weld.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

Evaluation of Antibacterial and Antidiabetic Potential of Silver Nanoparticles using Eugenia Uniflora L. Seed Extract

2020 ◽  
Vol 13 (6) ◽  
pp. 5217-5225
Author(s):  
Guru Kumar Dugganaboyana ◽  
Chethankumar Mukunda ◽  
Suresh Darshini Inakanally
Keyword(s):  
Biomedical Applications ◽  
Pathogenic Bacteria ◽  
Seed Extract ◽  
Drug Formulation ◽  
Visible Spectroscopy ◽  
Plant Materials ◽  
X Ray ◽  
Eugenia Uniflora ◽  
Uv Visible

In recent years, green nanotechnology-based approaches using plant materials have been accepted as an environmentally friendly and cost-effective approach with various biomedical applications. In the current study, AgNPs were synthesized using the seed extract of the Eugenia uniflora L. (E.uniflora). Characterization was done using UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The formation of AgNPs has confirmed through UV-Visible spectroscopy (at 466 nm) by the change of color owing to surface Plasmon resonance. Based on the XRD pattern, the crystalline property of AgNPs was established. The functional group existing in seed of E.uniflora extract accountable for the reduction of Ag+ ion and the stabilization of AgNPs was investigated. The morphological structures and elemental composition was determined by SEM and EDX analysis. With the growing application of AgNPs in biomedical perspectives, the biosynthesized AgNPs were evaluated for their antibacterial and along with their antidiabetic potential. The results showed that AgNPs are extremely effective with potent antidiabetic potential at a very low concentration. It also exhibited potential antibacterial activity against the three tested human pathogenic bacteria. Overall, the results highlight the effectiveness and potential applications of AgNPs in biomedical fields such as in the treatment of acute illnesses as well as in drug formulation for treating various diseases such as cancer and diabetes. It could be concluded that E. uniflora seed extract AgNPs can be used efficiently for in vitro evaluation of their antibacterial and antidiabetic effects with potent biomedical applications.

Modification of Collagen for Biomedical Applications: A Review of Physical and Chemical Methods

2016 ◽  
Vol 20 (17) ◽  
pp. 1797-1812 ◽  
Author(s):  
Xiaoyue Yu ◽  
Cuie Tang ◽  
Shanbai Xiong ◽  
Qijuan Yuan ◽  
Zhipeng Gu ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Chemical Methods ◽  
Physical And Chemical

Biomedical Applications and Patents on Metallic Nanoparticles

2020 ◽  
Vol 10 ◽  
Author(s):  
Geetanjali Singh ◽  
Pramod Kumar Sharma ◽  
Rishabha Malviya
Keyword(s):  
Metallic Nanoparticles ◽  
Biomedical Applications ◽  
Size Range ◽  
Biomedical Application ◽  
Chemical Reduction ◽  
Chemical Methods ◽  
Future Challenges ◽  
Biological Methods ◽  
Cancer Diagnosis And Therapy ◽  
Physical And Chemical

Aim/Objective: The author writes the manuscript by reviewing the literatures related to the biomedical application of metallic nanoparticles. The term metal nanoparticles are used to describe the nanosized metals with the dimension within the size range of 1-100 nm. Methods: The preparation of metallic nanoparticles and their application is an influential area for research. Among various physical and chemical methods (viz. chemical reduction, thermal decomposition, etc.) for synthesizing silver nanoparticles, biological methods have been suggested as possible eco-friendly alternatives. The synthesis of metallic nanoparticles is having many problems inclusive of solvent toxicity, the formation of hazardous byproducts and consumption of energy. So it is important to design eco-friendly benign procedures for the synthesis of metallic nanoparticles. Results: From the literature survey, we concluded that metallic nanoparticles have applications in the treatment of different diseases. Metallic nanoparticles are having a great advantage in the detection of cancer, diagnosis, and therapy. And it can also have properties such as antifungal, antibacterial, anti-inflammatory, antiviral and anti-angiogenic. Conclusion: In this review, recent upcoming advancement of biomedical application of nanotechnology and their future challenges has been discussed.

Synthesis of mussel-inspired polydopamine-gallium nanoparticles for biomedical applications

Nanomedicine ◽  
2021 ◽  
Author(s):  
Jean Valdir Uchôa Teixeira ◽  
Fátima Raquel Azevedo Maia ◽  
Mariana Carvalho ◽  
Rui Reis ◽  
Joaquim Miguel Oliveira ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Biomedical Applications ◽  
Adipose Derived Stem Cells ◽  
Cell Analysis ◽  
Shell Formation ◽  
X Ray ◽  
Alkali Medium ◽  
Reproducible Method ◽  
Gallium Nanoparticles

Aim: To established a simple, controlled and reproducible method to synthesize gallium (Ga)-coated polydopamine (PDA) nanoparticles (NPs). Materials & methods: PDA NPs were synthesized in alkali medium with posterior Ga shell formation due to ion chelation on the NP surface. Results: The obtained results with energy-dispersive x-ray spectroscopy confirmed the incorporation of Ga on the PDA NP surface. The cytotoxicity of Ga-coated PDA NPs was evaluated in vitro at different concentrations in contact with human adipose-derived stem cells. Further cell analysis also demonstrated the benefit of Ga-coated PDA NPs, which increased the cell proliferation rate compared with noncoated PDA NPs. Conclusion: This study indicated that Ga could work as an appropriate shell for PDA NPs, inducing cell proliferation at the analyzed concentrations.

Interaction of tungsten in dry sliding against steel under high density electric current

2019 ◽  
pp. 101-109 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin ◽  
Yu. P. Mironov
Keyword(s):  
Electrical Contact ◽  
Analysis Data ◽  
Dry Sliding ◽  
Sliding Surface ◽  
X Ray ◽  
Sliding Surfaces ◽  
Quenched Steel ◽  
Sliding Electrical Contact ◽  
A Current ◽  
Tungsten Steel

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel. 

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