Overview of Small Punch Test Arunkumar, S.
Metals and materials international,
06/2020, Letnik:
26, Številka:
6
Journal Article
Recenzirano
Small Punch Test (SPT) is an evolving small specimen test technique which has the potential to extract the mechanical properties from small volume specimens. This test method is used to determine the ...in situ mechanical properties of components in service for measuring the structural integrity and residual life. The pre-requisite for using this test is to establish correlations between SPT and conventional tests in priori. A number of correlations have been developed between traditional tests and SPT results for determining mechanical properties. The validity of these correlations have to be examined, as these are developed from a specified set of materials and testing conditions. To evaluate SPT and the developed correlations, it is crucial to understand the fundamentals of this test method, the different regimes of deformation experienced by the specimen and its sensitivity for various testing parameters. The attempt of this work is to relook the SPT as a whole and its potential to measure the different mechanical properties. This work lists the various SPT configurations, materials used in literature and the correlations developed. In addition, the influence of test parameters on SPT response, the viability of empirical or analytical relations used to extract mechanical properties and the general issues in SPT is discussed.
Graphic Abstract
Small punch creep (SPC) test has an important role in the remaining life calculation of in-service components functioning at high temperature and harsh ambience. Since the extraction of conventional ...full scale specimens from the components in service impairs its integrity, SPC test can be used as an alternative technique. This test method requires very thin disc similar to those needed for transmission electron microscopy (~ 3 mm diameter and 0.5 mm thick). The pre-requisite to employ this test technique is to establish correlations between uniaxial creep and SPC tests in priori. The purpose and scope of this work is to present briefly the principle of SPC testing method in comparison with uniaxial creep test. The differences in terms of specimen geometry and deformation process have been clearly brought out. The correlations developed by several researchers for determining the creep properties from SPC test along with uniaxial creep results for comparison is presented. The contributions by several authors in the direction of numerical simulation and fractography of SPC test is also briefed.
Graphic abstract
•δ and revel the ionic nature and the Same decreases with Sm3+ ion content.•Higher Ω4 revels the higher rigidity and higher covalency around the Sm3+ ion site.•τexp decreases with increase in Sm3+ ...ion due to energy transfer between Sm3+ ions.•Energy transfer between the Sm3+–Sm3+ ion site is due to dipole–dipole interaction.•0.5SmPbFB glass possesses higher A, βR and xτR, potential for laser applications.
Concentration dependent spectroscopic properties of Sm3+ ions are investigated in the prepared xSm:PbFB lead fluorobororate glasses with the composition (40−x)B2O3+20PbO+16PbF2+12Bi2O3+12ZnO+xSm2O3 (where x=0.05, 0.1, 0.5, 1, 2 and 3wt.%). Surface morphological analysis and structural behaviors of the prepared glasses have been explored through SEM, EDX, XRD, FTIR and Raman spectral analysis. The amorphous nature of the prepared glasses have been confirmed through XRD spectral analysis. The presence of BO3, BO4, B–O–B and Pb/Bi–O–B vibrational stretching units in the prepared glasses are confirmed through FTIR and Raman spectral analysis. The optical characterizations were carried out using UV–vis–NIR absorption, luminescence spectra and decay curves of the present glasses. The calculated bonding parameter (β¯ and δ) values reveal the ionic nature of the Sm–O bond in the prepared glasses. The Judd–Ofelt intensity parameters, Ωλ, were evaluated from the measured oscillator strength of the various absorption bands to study the bonding environment around the Sm3+ ions in the prepared glasses. From the JO intensity parameters and emission spectral measurements, the radiative properties such as stimulated emission cross-section (σPE), branching ratio (βR) and radiative lifetime (τR) for the 6HJ=5,7,9,11 emission transitions have been calculated. The experimental lifetime for the excited 4G5/2 level of the Sm3+ ions in the prepared glasses were calculated from the decay analysis and it is found to decrease with the increase in Sm3+ ion content. The decay curves are found to be non-exponential for the higher concentration of Sm3+ ion which is due to the efficient energy transfer between Sm3+–Sm3+ ions. To understand the nature of the energy transfer, the non-exponential decay rates were fitted to Inokuti–Hirayama (IH) model for S=6 which reveals that the energy transfer process is of dipole–dipole in nature. Among the prepared glasses, 0.5SmPbFB glass exhibit higher values of emission characteristic parameters and quantum efficiency for the 4G5/2 level suggesting that 0.5SmPbFB glass could be useful for optoelectronic device fabrication and laser applications.
The hybrid metal matrix composite is developed through stir casting process. In theAl7075 aluminium matrix material, two different combination of reinforcements are used to make hybrid composite and ...they are as (i) Al7075 + Al
2
O
3
+ SiC and (ii) Al7075 + Al
2
O
3
+ egg shell powder. The weight proportion of SiC and egg shell powder varied to study the influence of reinforcement. To validate the hybrid composite developed, electron microscopic imaging, density and hardness measured. Maximum surface hardness of 197 Hv is observed in the composite with 6% egg shell powder. The presence organic egg shell is in the form of calcium oxide which is harder than carbide particle reinforced in the hybrid composite material. It has posse’s natural strength compared to synthetic material and with less in density.The density of egg shell is less compared to SiC and alumina particle reinforcement. Electron images and the corresponding spectroscopic results infer that the reinforcements are equal distributed in the volume of composite. While casting the egg shell has been found in the form of calcium oxide along with aluminium and oxide elements. Since, the composite has less density which is light in weight compared to alumina or silicon carbide. With respect to sliding wear behaviour, the hybrid composite with Sample 1 (3% SiC) and Sample 4 (6% egg shell) has good wear resistance. With increase in hard particle the wear mechanism is abrasion and metal loss trend found increasing. The minimum of 0.25 mm
3
/min found with less load (10 N) and 0.42 mm
3
/min for 20 N load. On prolonged exposure more than 40 μm reached for maximum load. Increase in hard particle reinforcement (6% Al
2
O
3
+ 6% SiC) has induced severe surface damage due to abrasion on worn surface. Adhesive morphology and minimum wear are noticed with 6% Al
2
O
3
+ 6% SiC in hybrid composite. Therefore, it is confirmed that the reduced in hard particle or increase in egg shell may produce expected results on sliding wear behaviour.
Previous publications in 2011, 2016, and 2022 have presented lists of drugs associated with takotsubo cardiomyopathy (TCM). This review aims to provide updated drug lists that have been reported as ...potential causes of TCM.
Following the same methodology employed in previous reviews, a detailed investigation was carried out in the PubMed/Medline database from June 2022 to July 2023 to identify drug-induced TCM (DITC) case reports. Various search terms related to the drug-induced transient left ventricular ballooning syndrome, ampulla cardiomyopathy, apical ballooning syndrome, drug-induced broken heart syndrome, drug triggered takotsubo cardiomyopathy, takotsubo cardiomyopathy, and iatrogenic takotsubo cardiomyopathy were utilized. Filters for fulltext availability, case reports, human studies, and English language were applied. Articles reporting drugs associated with TCM development were included in the analysis.
Foremost 192 case reports were initially identified, with 75 drugs meeting the inclusion criteria after a thorough review. The latest revision identified seven drugs that might lead to TCM, with four drugs (57.14%) already reported in previous reviews and three drugs (42.86%) newly identified. Consequently, the updated drug list potentially triggering TCM in 2023 comprises a sum of 75 drugs.
The recent 75 drugs provided additional evidence linking to TCM development. The updated list predominantly includes drugs that induce sympathetic overstimulation, although some drugs on the list have unclear associations with sympathetic nervous system activation.
A highly selective and sensitive gas sensing material was prepared by decorating gold (Au) nanoparticles on zinc oxide (ZnO) nanostructure. First, zinc oxide architectures were synthesised through ...facile one-pot hydrothermal synthesis route by using zinc acetate as the metal precursors, ethanolamine as the organic Lewis base and water as the reaction medium. The versatile zinc oxide architectures such as (i) nanostars (ZNS), (ii) marigold flower (ZMF), (iii) nanorods assembled flower (ZNF) and (iv) nanorods (ZNR) were successfully synthesised by the controlled variation of the reaction medium mole ratio. The crystal structure and morphological evaluation of the as prepared material were investigated in detail by several analytical techniques, and the findings are consistent with each other. The carbon monoxide (CO) sensing ability of the as prepared materials was carried out at different sensing temperature (Ts≤300°C) and at different gas concentration (5–1000ppm). Gas sensing study clearly shows that the sensor responses are found to be morphology and surface area dependent. Among all the zinc oxide nanostructures, nanostars exhibits excellent sensitivity (SR∼31 toward 5ppm) at the optimized sensing temperature of 275°C. Further, to improve the sensing characteristics and to reduce the operating temperature, different wt% of gold nanopartilces were decorated on the surface of zinc oxide nano-stars by solution impregnation technique. Surface decoration of only 3wt% gold nanoparticles incorporated zinc oxide nanostars exhibits enhanced sensing response (SR ∼15 toward 50ppm) at 35°C with an excellent response (ΓRES ∼8s) and recovery (ΓREC ∼15s) time. Sensor also posses excellent selectivity toward CO compare to other interfering gases such as methanol, ethanol, acetone and hydrogen.
The Last four decades have witnessed the banning of several synthetic insecticides mainly due to the development of resistance to the target pests and due to hazardous effects on humans and the ...environment. Hence, the development of a potent insecticide with biodegradable and eco-friendly nature is the need of the hour. In the present study, the fumigant property, and biochemical effects of
L. (Dilleniaceae) were studied against three coleopterans stored-products insects. The bioactive enriched fraction (sub-fraction-III) was isolated from ethyl acetate extracts of
leaves and found toxic to rice weevil,
(L.) (Coleoptera); lesser grain borer
(L.) (Coleoptera) and red flour beetle,
(Herbst.) (Coleoptera) with the LC
values of 101.887, 189.908 and 115.1 µg/L respectively after 24 h exposure. The enriched fraction was found to inhibit the function of acetylcholinesterase (AChE) enzyme when tested against
, and
with LC
value of 88.57 µg/ml, 97.07 µg/ml, and 66.31 µg/ml respectively, in
condition. It was also found that the enriched fraction caused a significant oxidative imbalance in the antioxidative enzyme system such as superoxide dismutase, catalase, DPPH (2,2-diphenyl-1-picrylhydrazyl), and glutathione-S-transferase (GST). GCMS analysis of the enriched fraction indicates three major compounds namely, 6-Hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydrobenzofuran-2(4H)-one, 1,2-Benzisothiazol-3(2H)-one, and Benzothiazole, 2-(2-hydroxyethylthio)-. Finally, we concluded that the enriched fraction of
has insecticidal properties and the toxicity may be due to the inhibition of the AChE enzyme in association with oxidative imbalance created on the insect's antioxidant enzyme systems.
Petroleum fuels are commonly used for automobiles. However, the continuous depletion and exhaust gas emission causes serious problems. So, there is a need for an alternative eco-friendly fuel. ...Biodiesel is a type of fuel manufactured through a process called transesterification, which involves converting vegetable oils into a usable form. The process parameters of the transesterification process were optimized using the Taguchi method to achieve maximum biodiesel yield. However, the main problem of biodiesel is its high cost which could be reduced by using low-cost feedstock. To address this challenge, biodiesel (BCFAD) is derived from coconut fatty acid distillate (CFAD), a by-product obtained from refining coconut oil. This work uses BCFAD and BCFAD with Alumina nanoparticles as fuels. Alumina nanoparticles in the mass fraction of 25 ppm, 50 ppm, and 100 ppm are dispersed in BCFAD. The investigation results reveal an increase of 6.5% in brake thermal efficiency for BCFAD with 100 ppm nanoparticles when compared to BCFAD. There is a reduction of 29.29% of hydrocarbon and 34% of Carbon monoxide emissions with BCFAD100 in comparison with diesel. However, there is a marginal increase in NOx emission with the increase in nanoparticles. The heat release rate and cylinder pressure of BCFAD100 are comparable to diesel fuel. It was concluded that the utilization of BCFAD with a nanoparticle dispersion of 100 ppm is suitable for direct use as fuel in diesel engines.
Abstract A multi‐stimuli responsive tetraphenyl substituted tripehnylamine‐based aggregation induced emissive (AIE) material coupled with spiropyran was prepared. Owing to the presence of AIE and ...photochromic moiety, the molecule exhibits emissive aggregates, photochromism, and acidochromism. The multiple stimuli sensitive behavior of the molecule was explored for anti‐counterfeiting behavior on TLC plate and commercial banknotes. The fluorogenic and photogenic response under UV and visible light established the potential of the candidate as a new generation encryption material.
Dy3+ ions doped Bismuth sodium fluoroborate glasses (BiNFBxD) have been prepared following the melt quenching technique and characterized through XRD, FTIR, UV-Vis-NIR absorption, luminescence and ...decay measurements for developing potential WLEDs and yellow lasers. The local symmetry around the Dy3+ ions in the prepared glasses were investigated through optical basicity, covalent character factor, bonding parameter, Judd-Ofelt parameters and Y/B intensity ratio values. The least squares fitting method have been employed to determine the Judd-Ofelt intensity parameters Ωλ to study the nature of bonding and symmetry orientation of the Dy-ligand field environment and to derive the radiative properties for the various emission transitions of the Dy3+ ions. The higher spectroscopic quality factor Ω4/Ω6 values of the prepared glasses indicate its suitability for the fabrication of laser devices and the values were compared with the reported literature. While exciting the Dy3+ doped title glasses at 452 nm (6H15/2 → 4I15/2), the emission bands 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) were observed at 482 nm, 575 nm and 679 nm, respectively. The radiative properties like stimulated emission cross-section (σPE), transition probability (A), effective wavelength (λeff), branching ratio (βR) and experimental lifetimes (τm) for all the emission bands of the Dy3+doped title glasses have been computed. From the luminescence spectra the Y/B ratio values, CIE chromaticity color coordinates and Color Correlated Temperature (CCT) for different concentrations of Dy3+ ions were calculated. The CIE chromaticity co-ordinate values of the present glasses suggest their suitability for the development of visible luminescent photonic devices and white light applications. The decay curves pertaining to the 4F9/2 level have been measured for the title glasses and the fall in lifetime values with the increase in Dy3+ ions concentration could be attributed to the cross-relaxation takes place among the Dy3+ ions and the non-radiative multiphonon relaxation process takes place through the phonon modes of the glass host. The non-exponential behavior of the decay curves have been analyzed through Inokuti-Hirayama model to identify the nature of the energy transfer process takes place among the Dy3+ ions and the dipole-dipole interaction(s) is responsible for the dominant energy transfer process.
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•The higher basicity, negative magnitude of δ values indicates the ionic nature of the DyO bond.•The higher Ω2 intensity parameter values reveal the higher asymmetric local environment around the Dy3+ ion site.•The CCT and color purity values of BiNFB0.5D glass highlight the nature of pure white light.•The CIE 1931 chromaticity coordinates confirm their potential of suitability for WLED applications.•The decay curves fitted to IH model for S = 6 reveals the dipole-dipole interaction between Dy3+ ions.
