Polarization Measurements Research Articles

Synthesis of Schiff bases of 4-methoxybenzyl amine and hydrazide derivatives and their application in corrosion inhibition of mild steel in 1.0 M HCl

In this work, Schiff bases of 4-methoxybenzyl amine and hydrazide derivatives containing succinic (BMSHE), oxalyl (BMOHE), and phenylaceto (BMPHE) have been synthesized and applied for corrosion inhibition of mild steel (MS) in 1.0 M HCl. The synthesized compounds are characterized by Fourier-transform infrared (FTIR) and H1 nuclear magnetic resonance (NMR) spectroscopy. The FTIR and H1 NMR results have confirmed their formation through the presence of functional groups and hydrogen associated with them. Corrosion mitigation examination is done by polarization measurements (PM), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) equipped with energy dispersive X-rays (EDX), and atomic force microscopy (AFM). All inhibitors demonstrated notable efficacy in preventing MS in HCl (BMSHE-88%, BMOHE-84%, and BMPHE-72%). As per corrosion potentials, BMOHE and BMPHE have been found to be mixed types of inhibitors, and BMSHE is noticed as a cathodic inhibitor. The SEM results demonstrated how these hydrazide derivatives prevented corrosion by covering the MS surface. The EDX analysis of the surfaces has revealed that the inhibited MS contains lower amounts of O and Cl, which indicate that the inhibitors prevent MS in HCl. AFM analysis shows that the surfaces of MS in the presence of the inhibitors are damaged less than in their absence, which reveals the same facts as told above. The inhibition of MS by BMSHE, BMOHE, and BMPHE is also explained with a reason after analyzing the results.

Minimize flow-induced uncertainty in polarization sensitive optical coherence tomography imaging using eigen decomposition.

Blood flow alters the scattering behavior of penetration light, causing instability in the polarization state to emerge at the underlying tissue during polarization-sensitive optical coherence tomography (PSOCT). We propose an eigen decomposition method to meet this challenge, where the static and dynamic scattering signals are separated for PSOCT to provide the polarization measurements of the tissue of interest that is located beneath the blood flow. Using flow phantoms made by Intralipid solution and 3D-printed birefringent material, we show the flow-induced effects on the measurements of sample birefringent properties of optical axis, phase retardation, and degree of polarization uniformity. We demonstrate the usefulness of the proposed method through in vivo imaging of the human nail fold.

Effect of metalloid element on the microstructural and mechanical properties of AlCoCrCuFeNi high-entropy alloys

ABSTRACT The impact of the metalloid element silicon (Si) addition on the microstructural and mechanical properties of the AlCoCuCrFeNiSix high-entropy alloy system is examined in this paper. The alloys were synthesized using a vacuum arc melting route. X-ray diffraction was used to analyse the current high-entropy alloys’ phase formation to comprehend the alloying process’s behaviour. It is evident from the peak pattern of the X-ray diffraction that the inclusion of Si promotes the growth of body-centred cubic structures. The microhardness and wear resistance were increased by increasing the Si content from 0 to 0.9. Si presence enhances the hardness of the alloys and strengthens the grain boundary. Improved hardness and wear resistance results from the enhanced body-centred cubic-phase formation, which poses a barrier to the dislocation movement and prevents further deformation. Furthermore, the inclusion of Si improved corrosion resistance in potentiodynamic polarization measurements. Excellent compressive strength is possessed by all of the high-entropy alloys with Si addition.

New hybrid organic-inorganic conversion coating applied on the Al2024 substrate: Electrochemical, adhesion and surface study

Health problems caused by chromate conversion coatings promoted new research for discovering environmentally-friendly conversion coatings. In this study, Ti-Zr conversion coating (Ti-Zr) was deposited on the aluminum surface in the presence of nickel sulfate (Ti-Zr-Ni) and adipic acid (Ti-Zr-AA). Polarization and electrochemical impedance spectroscopy (EIS) measurements were employed to evaluate the anti-corrosion properties. Surface analysis was carried out using field emission scanning electron microscope (FE-SEM) and Atomic force microscopy (AFM). The results revealed that the Ti-Zr-Ni treatment inhibited the corrosion progression to a significant degree. The polarization resistance showed a significant increase (Rp= 58835 ohm.cm2) in Ti-Zr-Ni treatment in comparison with Ti-Zr conversion coating (Rp= 4450 ohm.cm2) and Ti-Zr-AA sample (Rp= 15058 ohm.cm2). The presence of Ni in the Ti-Zr composition, not just gave rise to the synergism but also played an important role as catalyst to further help avoiding further material degradation. Moreover, the presence of additives (nickel sulfate and adipic acid) enhanced the anti-corrosion resistance of coating by modification of surface morphology according to FE-SEM and AFM images. Anti-corrosion properties and adhesion strength of samples in a fully coated system were also investigated by EIS and pull-off tests, respectively, which revealed that the delamination of the Ti-Zr-Ni sample was lowest among others, and this sample showed better barrier performance even after 6 weeks of immersion in the corrosive environment.

X-ray spectropolarimetric characterization of GX 340+0 in the horizontal branch: A highly inclined source?

We report the first detection of X-ray polarization in the horizontal branch for as obtained by the Imaging X-ray Polarimetry Explorer ( A polarization degree of 4.3<!PCT!>pm 0.4<!PCT!> at a confidence level of 68<!PCT!> is obtained. This value agrees with the previous polarization measurements of Z-sources in the horizontal branch. The spectropolarimetric analysis, performed using a broadband spectral model obtained by and quasi-simultaneous observations, allowed us to constrain the polarization for the soft and hard spectral components that are typical of these sources. The polarization angle for the two components differs by sim This result can be explained by a misalignment of the NS rotation axis with respect to the accretion disk axis. We compared the results with the polarization that is expected in different models. Theoretical expectations for the polarization of the disk and the Comptonization components favor a higher orbital inclination for than 60 as expected for Cyg-like sources. This is in contrast with the results we report for the reflection component based on the broadband spectrum.

Surface modification of surgical suture by chitosan-based biocompatible hybrid coatings: In-vitro anti-corrosion, antibacterial, and in-vivo wound healing studies

This work aims to develop chitosan-based biocompatible hybrid coatings on synthetic surgical sutured by direct current electrophoretic deposition (DC-EPD) method. The chitosan (CS), curcumin (CR), aloe-vera (AV), and 2-aminothiazolidin-4-one-5-ethanoic acid (AT) were used as suspensions of varying combinations and compositions (A–I). Each suspension has a further 05 samples (Aa–Ae–Ia–Ie) at selected DC-EPD set parameters (2–10 V, t; 240 s, D; 1 cm). Potentiodynamic polarization measurements (PDP) were carried out in the ringer solution. Among all samples, Ed (CS, 1.6 g/L; 8 V) and Hb (CS–CR–AT, 1.6 g/Leach; 4 V) have shown greatest corrosion inhibition efficiency (IEPDP: 99 %), least corrosion rates (CR; 0.001 mm/y and 0.017 mm/y, respectively), and least corrosion current density (Icorr.; 0.01 A cm−2). SEM and FTIR further confirmed these two best coatings stable and corrosion resistant before and after performing corrosion test, while the coating thickness by profilometry test was found to be greater (16.28 μm) for Hb. Mechanical stress and strain of bare and coated samples were found to have no significant difference. Antibacterial activity revealed greater resistance of Hb against S. aureus as compared to Ed. In-vivo incision wound model study further revealed better healing and less inflammation with coated sutures with comparatively enhanced wound healing effect of Hb coated suture.

New high-precision measurement system for electron–positron pairs from sub-GeV/GeV gamma-rays in the emulsion telescope

The GRAINE project observes cosmic gamma-rays, using a balloon-borne emulsion-film-based telescope in the sub-GeV/GeV energy band. We reported in our previous balloon experiment in 2018, GRAINE2018, the detection of the known brightest source, Vela pulsar, with the highest angular resolution ever reported in an energy range of >80MeV. However, the emulsion scanning system used in the experiment was designed to achieve a high-speed scanning, and it was not accurate enough to ensure the optimum spatial resolution of the emulsion film and limited the performance. Here, we report a new high-precision scanning system that can be used to greatly improve the observation result of GRAINE2018 and also be employed in future experiments. The scanning system involves a new algorithm that recognizes each silver grain on an emulsion film and is capable of measuring tracks with a positional resolution for the passing points of tracks of almost the same as the intrinsic resolution of nuclear emulsion film (∼70 nm). This resolution is approximately one order of magnitude smaller than that obtained with the high-speed scanning system. With this scanning system, an angular resolution for gamma-rays of 0.1° at 1GeV is expected to be achieved. Furthermore, we successfully combine the new high-precision scanning system with the existing high-speed scanning system, enabling the high-speed and high-precision measurements. Employing these techniques, we reanalyze the gamma-ray events detected previously by only the high-speed scanning system in GRAINE2018 and obtain an about three times higher angular resolution (0.22°) in the 500–700MeV energy range. Adopting this technique in future observations may provide new insights into the gamma-ray emission from the Galactic center region and may realize polarization measurements of high-energy cosmic gamma-rays.

Unlocking the power of Dryopteris filix mas extract: A green solution for corrosion inhibition in A210Gr carbon steel in acidified 3% wt. NaCl environment

This study investigates the corrosion inhibition effectiveness of Dryopteris filix-mas L. (DFM) extract for A210Gr carbon steel in a 3 % NaCl solution. The DFM ethanolic extract was successfully prepared and comprehensively characterized using a combination of spectroscopic and physicochemical techniques, including HPLC, FTIR, and NMR (1H and 13C). These analyses confirmed the presence of key phenolic compounds, with Quercetin-3-O-diglucoside (Q3ODG) being the major component, comprising 82.14 % peak area as identified by HPLC. The extract, obtained via an economical ethanol extraction method, exhibited a maximum inhibition efficiency up to 88 % at a concentration of 400 ppm, as determined through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), potentiodynamic polarization (PDP), and weight loss measurements. Temperature studies revealed a drop in efficiency to 70.14 % at 323 K, indicating a temperature-sensitive inhibition mechanism. Extended immersion times led to a slight decrease in efficiency due to partial desorption, though significant protection remained after 72 h. The primary corrosion inhibition mechanism was determined to be physisorption, following the Langmuir isotherm model, with a ΔGads0 value of − 24.02 kJ/mol, indicating a spontaneous adsorption process. Thermodynamic analysis revealed an increase in Ea from 22.11 kJ/mol (blank) to 56.61 kJ/mol (400 ppm), confirming the formation of a strong protective barrier. Surface characterization techniques, including FTIR, XRD, SEM, and AFM, further confirmed the presence of a protective film rich in polar organic compounds. Complementary Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) studies provided detailed insights into the molecular interactions, highlighting the key role of hydrogen bonding and van der Waals forces in the adsorption of Q3ODG onto the steel surface. These findings underscore the potential of DFM extract as an effective and sustainable corrosion inhibitor, advancing the application of biocompounds in corrosion control and encouraging further exploration of their industrial applications and environmental benefits.

Measurement of microwave polarization using two polarization orthogonal local microwave electric fields in a Rydberg atom-based mixer.

We propose and demonstrate what we believe to be a novel method for measuring the polarization direction of a microwave electric field in a single measurement using a Rydberg atom-based mixer with two orthogonally polarized local microwave electric fields. This approach eliminates the need for physical rotation of the local field, allowing the polarization angle of the signal field to be determined directly by measuring the ratio of the two beat signals. Furthermore, introducing a weak static magnetic field enables the utilization of the Zeeman effect and exploitation of polarization asymmetry. This distinction allows for determining the polarization direction of the microwave field is θ or 180° - θ within the 0 to 180-degree range. The capability to measure microwave polarization in real-time across this range is very valuable for applications in microwave sensing and information transmission.

Improved Electrode Performance Using Fine‐Tuned Poly(arylene piperidinium) Ionomers In Anion Exchange Membrane Fuel Cells

AbstractIonomers based on poly(arylene piperidinium)s with varying ion exchange capacities are evaluated in different combinations of anode and cathode electrodes in anion exchange membrane fuel cells. The operational conditions are chosen with an asymmetrical regime including a dry anode with 50% relative humidity at the inlet, and full humidification at the cathode. Polarization and impedance measurements are carried out in potentiostatic steps within 0.3–0.9 V and distribution of relaxation times analysis is utilized to deconvolute resistance contributions. The results show that the best cell performance is achieved with both electrodes utilizing an ionomer with the highest ion exchange capacity (IEC) of 2.79 meq g−1. Cells built exclusively from this ionomer achieved a peak power density of 1.01 W cm−2. Deconvolution of the resistance contributions revealed the impact of water content on the effective charge transfer resistance in both electrodes and a diffusion resistance associated with the movement of water from anode to cathode side. The higher conductivity and water uptake of the high IEC ionomer resulted in a reduction of both resistance contributions, leading to the highest performance under the conditions evaluated. These findings provide important insights into how to tailor the electrode layers for optimum fuel cell output.

Analysis of interference fringes in a long-wave infrared full Stokes polarimeter based on rotating waveplates

In the long-wave infrared (LWIR, 8–15 µm) band, the interference effect of polarization elements becomes an issue in polarimetry due to defects in the anti-reflective coatings. The paper describes an analysis and optimization method for the rotating-waveplates-based Stokes polarimeter, to eliminate interference fringes and improve polarization measurement accuracy in LWIR. An interference model was established based on the theory of polarized light and thin-film optics. Different modulation schemes were simulated and analyzed to obtain an optimized Stokes polarimeter, reducing the instrumental polarization to less than 1E-3. Furthermore, experimental validation was conducted by the Accurate Infrared Magnetic Field Measurements of the Sun (AIMS) telescope. The result shows that the instrumental polarization was less than 2E-3, consistent with the simulation.

Electrochemical, surface, and theoretical investigations of palm kernel shell extract as an effective inhibitor for carbon-steel corrosion in 1M HCl solution.

Herein, we employed palm kernel shell extract (PKSE) as an eco-friendly inhibitor for carbon steel in acidic-induced corrosion. The corrosion inhibition of PKSE on carbon steel in 1M HCI solution was investigated by electrochemical impedance spectroscopy, weight loss, and potentiodynamic polarization measurements. The surface was characterized by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. Moreover, the elastic modulus and hardness tests were conducted. Weight loss measurements revealed that the optimum concentration of inhibitors is 500ppm with 95.3% inhibition efficiency in 1M HCl solution. Electrochemical results showed that the inhibitor could exhibit excellent corrosion inhibition performance and displayed mixed-type inhibition. The electrochemical impedance spectroscopy analysis shows that the inhibition performance increases by increasing the concentration of PKSE. The surface studies ensure the PKSE effectiveness in carbon steel surface damage reduction. Also, the adsorption of PKSE molecules on the carbon steel surface occurs according to the Langmuir isotherm model. The primary goal of this investigation was the utilization of palm kernel shell extract as corrosion inhibitor for 1018 low carbon steel in 1M HCl solution, which highlights its novelty. The present results will be helpful to uncover the versatile importance of palm kernel shell compounds in the corrosion inhibition process.

Enhancing corrosion resistance of lightweight metal alloys through laser shock peening

In this study, we investigated the effects of laser shock peening (LSP) on the corrosion resistance of lightweight metal alloys, specifically AA6061 and AZ31. LSP was performed underwater, using a nanosecond pulse laser and without using a protective coating or layer on the workpiece. The corrosion behaviors of these alloys were analyzed through electrochemical tests, including open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The results demonstrated that LSP significantly improved the polarization resistance, and higher laser power intensities led to increased corrosion resistance and reduced corrosion rates. This enhancement in anti-corrosion performance is attributed to the formation of a protective oxide layer on the surface, acting as a barrier against corrosion. The findings underscore the potential of laser surface treatment as a viable technique for enhancing the corrosion resistance of lightweight metal alloys.

An Antiferroelectric‐Coated Metal Foam Infiltrated with Liquid Metal as a Dielectric Capacitor

Nickel metal foams serve as both a substrate and bottom electrode for a dielectric capacitor using atomic‐layer deposition (ALD) and a eutectic gallium–indium (EGaIn) liquid metal (LQM) counter electrode. The conformal dielectric has a composition of 6.25% Al–HfO2 in the antiferroelectric phase, confirmed with polarization versus electric field measurements. Liquid EGaIn is pressure‐infiltrated within the coated foams to form the dielectric capacitor. Capacitances up to 4 μF are realized. Calorimetry of the infiltrated capacitor shows a 60 J g−1 latent heat upon melting a frozen EGaIn electrode, suggesting that the phase change can alleviate thermal deviations from pulsed power capacitor operation. Infiltrated capacitors are also shown to survive bending and freeze–thaw cycles. The metal foam–ALD dielectric–LQM capacitor shows a combined set of thermal and electrical properties not available in other classes of capacitors.

Hardness and corrosion resistance of Zn coatings on mild steel obtained by electrodeposition and hot-dip galvanization

The purpose of this work is a comparative study of the characteristics of the layers of Zn on a substrate of mild steel from two different processes (electrodeposition and galvanizing), and to review the progress that has been made in understanding the intermetallics phases’ effect on the corrosion behavior. The obtained Zn-containing film was investigated using diverse instrumental methodologies such as microhardness, X-ray diffraction, and potentiodynamic polarization measurements. This study allows the conclusion that the layers of Zn developed have: a homogeneous structure and good hardness. The corrosion test results showed an improvement in corrosion resistance for electrodeposition coatings compared with galvanizing coatings. XRD results identify that the electrodeposition and the galvanizing coatings have similar phases and the maximum hardness is obtained for the galvanizing process. Intermetallic phases were found to influence the corrosion behavior of mild steel. The results show that the size of Fe–Zn particles gradually decreases with the immersion time.

Polarization enhancement based on holographic recording modulation in rubidium vapor

Spin polarization is an important parameter of magnetometers, and is essential for enhancing the stability and sensitivity of magnetic field measurements. The interference light field formed by the small angle interference of two right-handed circularly polarized beams remains right-handed circularly polarized, which can polarize alkali metal atoms and enable holographic recording. To analyze the effect of holographic modulation on spin polarization, we first performed holographic recordings in two cells: one containing pure 87Rb vapor, and the other containing 87Rb atoms, N2 and He, which is commonly used in atomic magnetometers. Holographic recordings from the optical field amplification and the influences of signal light detuning and temperature on the hologram were experimentally studied. The diffraction efficiency can be obtained by detecting the intensity of the diffracted beam, and the diffraction efficiency reached 5% in the 87Rb-He-N2 cell. Measurements of the spin polarization, demonstrated that holographic record modulation effectively enhanced spin polarization in the two cells, and the presence of a buffer gas contributed to spin polarization. This method increased the polarizability of the signal light to the atoms by 4.3% and is expected to achieve higher polarizability through the fine-tuning of the light field. The results show that the holographic light field may aid in further improving the sensitivity of atomic magnetometers under the premise of constant signal intensity.

Fluorescence Polarization Assay for Infection Diagnostics: A Review

Rapid and specific diagnosis is necessary for both the treatment and prevention of infectious diseases. Bacteria and viruses that enter the bloodstream can trigger a strong immune response in infected animals and humans. The fluorescence polarization assay (FPA) is a rapid and accurate method for detecting specific antibodies in the blood that are produced in response to infection. One of the first examples of FPA is the non-competitive test for detecting brucellosis in animals, which was followed by the development of other protocols for detecting various infections. Fluorescently labeled polysaccharides (in the case of brucellosis and salmonellosis) or specific peptides (in the case of tuberculosis and salmonellosis, etc.) can be used as biorecognition elements for detecting infections. The availability of new laboratory equipment and mobile devices for fluorescence polarization measurements outside the laboratory has stimulated the development of new fluorescence polarization assays (FPAs) and the emergence of commercial kits on the market for the detection of brucellosis, tuberculosis, and equine infectious anemia viruses. It has been shown that, in addition to antibodies, the FPA method can detect both viruses and nucleic acids. The development of more specific and sensitive biomarkers is essential for the diagnosis of infections and therapy monitoring. This review summarizes studies published between 2003 and 2023 that focus on the detection of infections using FPA. Furthermore, it demonstrates the potential for using new biorecognition elements (e.g., aptamers, proteins, peptides) and the combined use of FPA with new technologies, such as PCR and CRISPR/Cas12a systems, for detecting various infectious agents.

Hf0.4Zr0.6O2 Thickness-Dependent Transfer Characteristics of InxZn1-xOy Channel Ferroelectric FETs.

We investigate how the threshold voltage (VT) is adjusted to create a memory window (MW) in ferroelectric field-effect transistors (FeFETs) composed of ferroelectric Hf0.4Zr0.6O2 and InZnO (In2O3:ZnO = 9:1 wt %). Temperature-dependent polarization measurements reveal a dipole switching in Hf0.4Zr0.6O2. The properties of the n-type InZnO channel are examined by fabricating an oxide transistor with an HfO2 gate dielectric. Upon replacement of HfO2 with Hf0.4Zr0.6O2 in the oxide transistor, a counterclockwise MW is observed. Specifically, as the Hf0.4Zr0.6O2 thickness increases from 16 to 24 nm, the VT of the FeFET after a + gate voltage (VG) sweep remains nearly constant, while the VT after a -VG sweep shifts significantly from -0.9 to 0.5 V. The enlarged MW of approximately 2 V, which is proportional to the Hf0.4Zr0.6O2 thickness in the FeFET, can be explained by considering the balance between VG controllability across the gate stack and the ferroelectric switching of Hf0.4Zr0.6O2.

Probing Magnetic Fields in Young Supernova Remnants with IXPE

Synchrotron emission from the shocked regions in supernova remnants provides, through its polarization, crucial details about the magnetic field strength and orientation in these regions. This, in turn, provides information on particle acceleration in these shocks. Due to the rapid losses of the highest-energy relativistic electrons, X-ray polarization measurements allow for investigations of the magnetic field to be carried outvery close to the sites of particle acceleration. Measurements of both the geometry of the field and the levels of turbulence implied by the observed polarization degree thus provide unique insights into the conditions leading to efficient particle acceleration in fast shocks. The Imaging X-ray Polarimetry Explorer (IXPE) has carried out observations of multiple young SNRs, including Cas A, Tycho, SN 1006, and RX J1713.7−3946. In each, significant X-ray polarization detections provide measurements of magnetic field properties that show some common behavior but also considerable differences between these SNRs. Here, we provide a summary of results from IXPE studies of young SNRs, providing comparisons between the observed polarization and the physical properties of the remnants and their environments.

X-Ray and Multiwavelength Polarization of Mrk 501 from 2022 to 2023

We present multiwavelength polarization measurements of the luminous blazar Mrk 501 over a 14 month period. The 2–8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100 ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR, Swift/XRT, and/or XMM-Newton. Complementary optical–infrared polarization measurements were also available in the B, V, R, I, and J bands, as were radio polarization measurements from 4.85 GHz to 225.5 GHz. Among the first five IXPE observations, we did not find significant variability in the X-ray polarization degree and angle with IXPE. However, the most recent sixth observation found an elevated polarization degree at >3σ above the average of the other five observations. The optical and radio measurements show no apparent correlations with the X-ray polarization properties. Throughout the six IXPE observations, the X-ray polarization degree remained higher than, or similar to, the R-band optical polarization degree, which remained higher than the radio value. This is consistent with the energy-stratified shock scenario proposed to explain the first two IXPE observations, in which the polarized X-ray, optical, and radio emission arises from different regions.