Single Sweep Research Articles

Mimicking somatic behavior of neurons using the integrate and fire model of 2D SnS memristive switching characteristics

This Letter presents the fabrication and characterization of a 2D SnS memristor, proposing its integrate and fire (I&F) model as a potential hardware implementation of neuronal somatic behavior. The memristor comprises a thin layer of tin (II) sulfide (SnS) sandwiched between copper (Cu) electrodes on a silicon (Si) substrate. This structure exhibits an impressive Roff:Ron ratio of 103 at a read voltage Vrd of 0.25 V with exceptionally low switching Vsw and set Vset voltages of 0.3 and 0.35 V, respectively, with ∼3 order variation between the maximum Rmax and Rmin resistances offered during single voltage sweep cycle. We have explained the memristive behavior using the dual ionic conduction mechanism in the SnS active layer. We extracted the real-time band diagram of SnS using ultraviolet photoelectron spectroscopy, explaining the low Vsw observed. We propose that the emulation of the I&F artificial neuron model exhibited by the fabricated device could serve as a promising application in the field of artificial neuron spiking.

Practical considerations for the amplification of electro-optically detected THz signals

Advances in THz methods and applications require the detection of weak THz pulsed signals. One solution to this problem is to amplify weak signals using optically biased electro-optical (EO) techniques. Several different EO amplification schemes are compared. The simplest of these involves using a non-polarizing beam splitter followed by two quarter-wave plates set to small positive and negative angles, respectively. The signals are then passed through polarizers perpendicular to the polarization of the 800 nm EO detector crystal gating beam. As long as sufficient intensity is present in the gate pulse for linear photodiode detection, amplification of up to 10 times with dynamic ranges for single sweep scans of >104 is obtained.

Genetic diversity during selective sweeps in non-recombining populations.

Selective sweeps, resulting from the spread of beneficial, neutral, or deleterious mutations through a population, shape patterns of genetic variation at linked neutral sites. While many theoretical, computational, and statistical advances have been made in understanding the genomic signatures of selective sweeps in recombining populations, substantially less is understood in populations with little/no recombination. We present a mathematical framework based on diffusion theory for obtaining the site frequency spectrum (SFS) at linked neutral sites immediately post and during the fixation of moderately or strongly beneficial mutations. We find that when a single hard sweep occurs, the SFS decays as 1/ x for low derived allele frequencies ( x ), similar to the neutral SFS at equilibrium, whereas at higher derived allele frequencies, it follows a 1/ x 2 power law. These power laws are universal in the sense that they are independent of the dominance and inbreeding coefficient, and also characterize the SFS during the sweep. Additionally, we find that the derived allele frequency where the SFS shifts from the 1/ x to 1/ x 2 law, is inversely proportional to the selection strength: thus under strong selection, the SFS follows the 1/ x 2 dependence for most allele frequencies, resembling a rapidly expanding neutral population. When clonal interference is pervasive, the SFS immediately post-fixation becomes U-shaped and is better explained by the equilibrium SFS of selected sites. Our results will be important in developing statistical methods to infer the timing and strength of recent selective sweeps in asexual populations, genomic regions that lack recombination, and clonally propagating tumor populations.

P‐23: Low Power A‐PWM μLED Pixel Circuit of Progressive‐mode Using Single Sweep Signal for Mobile Displays

An analog pulse‐width‐modulation (A‐PWM) Micro‐LED (μLED) pixel circuit based on low‐temperature‐polysilicon (LTPS) thin‐film transistors (TFTs) for mobile displays is proposed. The progressive‐emission mode is implemented using a single Sweep (SW) signal by in‐pixel logic operation circuits. By adjusting the emission time of the progressive‐emission mode, the μLED is biased with the maximum quantum efficiency (EQE). Consequently, the static power consumption of proposed pixels is reduced by 29.2%, compared with conventional schemes.

Laser-sound reproduction by pulse amplitude modulation audio streams

Recently, the possibility to reproduce complex continuous acoustic signals via pulsed laser-plasma sound sources was demonstrated. This was achieved by optoacoustic transduction of dense laser pulse trains, modulated via single- or multi-bit Sigma–Delta, in the air or on solid targets. In this work, we extend the laser-sound concept to amplitude modulation techniques. Particularly, we demonstrate the possibility of transcoding audio streams directly into acoustic pulse streams by analog pulsed amplitude modulation. For this purpose, an electro-optic modulator is used to achieve pulse-to-pulse amplitude modulation of the laser radiation, similarly to the multi-level Sigma–Delta method. The modulator is directly driven by the analog input stream through an audio interface. The performance of the system is evaluated at a proof-of-principle level for the reproduction of test audio signals such as single tones, double tones and sine sweeps, within a limited frequency range of the audible spectrum. The results are supported by computational simulations of the reproduced acoustic signals using a linear convolution model that takes as input the audio signal and the laser-generated acoustic pulse profile. The study shows that amplitude modulation allows for significant relaxation of the laser repetition rate requirements compared to the Sigma–Delta-based implementation, albeit at the potential cost of increased distortion of the reproduced sound signal. The nature of the distortions is analyzed and a preliminary experimental and computational investigation for their suppression is presented.

Single Voltammetric Sweep Calibration-Free Interrogation of Electrochemical Aptamer-Based Sensors Employing Continuous Square Wave Voltammetry.

Continuous square wave voltammetry (cSWV) is a technique that enables the continuous collection of current data (at 100 kHz) to maximize the information content obtainable from a single voltammetric sweep. This data collection procedure results in the generation of multiple voltammograms corresponding to different effective square wave frequencies. The application of cSWV brings significant benefits to electrochemical aptamer-based (E-AB) sensors. The E-AB sensor platform permits continuous real-time monitoring of small biological molecules. Traditionally, E-AB sensors report only on changes in analyte concentration rather than absolute quantification in matrices when basal concentrations are not known a priori. This is because they exhibit a voltammetric peak current even in the absence of a target. However, using a dual-frequency approach, calibration-free sensing can be performed effectively, eliminating the sensor-to-sensor variation by taking ratiometric current responses obtained at two different frequencies from two different voltammetric sweeps. In employing our approach, cSWV provides a great advantage over the conventionally used square wave voltammetry since the required voltammograms are collected with a single sweep, which improves the temporal resolution of the measurement when considering the current at multiple frequencies for improved accuracy and reduced surface interrogation. Moreover, we show here that using cSWV provides significantly improved concentration predictions. E-AB sensors sensitive to ATP and tobramycin were interrogated across a wide range of concentrations. With this approach, cSWV allowed us to estimate the target concentration, retaining up to an ±5% error of the expected concentration when tested in buffer and complex media.

The Effect of Swirl Number on Lean Blow Out Limits of Lean Direct Injection Combustors

Abstract This is the first study where a single variable sweep of SN is conducted to assess its impact on lean blowout limits (LBO) in a liquid-fueled lean direct injection (LDI) combustor. This study uses a scaled NASA SV-LDI (Swirl Venturi—Lean Direct Injection) hardware and is concerned with the impact of swirl number on the lean blow-out limit of a single-element LDI system at atmospheric pressure. The swirl numbers (SN) were varied from 0.31 to 0.66 using continuously variable active swirl number control system that was developed in-house. It is shown that the minimum operating equivalence ratio is a linearly increasing function of swirl number. While previous literature agrees with the positive slope for this correlation, past work has suggested that the LBO limit is proportional to the swirler vane angle which is shown to be untrue for LDI systems. By actively varying the swirl number, it is proven that LBO is proportional to SN, and it is well known that SN is not proportional to swirler vane angle. Increased SN reduces LBO margin because the better-mixed, high swirl dilutes locally rich pockets of fuel–air mixture in a globally lean flow. In addition to a baseline venturi, which was scaled from NASA's geometry, two other venturis were tested. A low-pressure loss venturi with a large throat diameter showed poor blow-out performance whereas a parabolically profiled venturi improved LBO over the baseline for the same swirl number.

Nonlinear frequency modulation for Fourier transform ion mobility mass spectrometry improves experimental efficiency

Through optimization of terminal frequencies and effective sampling rates, we have developed nonlinear sawtooth-shaped frequency sweeps for efficient Fourier transform ion mobility mass spectrometry (FT-IM-MS) experiments. This is in contrast to conventional FT-IM-MS experiments where ion gates are modulated according to a linear frequency sweep. Linear frequency sweeps are effective but can be hindered by the amount of useful signal obtained using a single sweep over a large frequency range imposed by ion gating inefficiencies, particularly small ion packets, and gate depletion. These negative factors are direct consequences of the inherently low gate pulse widths of high-frequency ion gating events, placing an upper bound on FT-IM-MS performance. Here, we report alternative ion modulation strategies. Sawtooth frequency sweeps may be constructed for the purpose of either extending high-SNR transients or conducting efficient signal-averaging experiments for low-SNR transients. The data obtained using this approach show high-SNR signals for a set of low-mass tetraalkylammonium salts (<1000 m/z) where resolving powers in excess of 500 are achieved. Data for low-SNR obtained for multimeric protein complexes streptavidin (53 kDa) and GroEL (800 kDa) also reveal large increases in the signal-to-noise ratio for reconstructed arrival time distributions.

Study on the combined influence of aerodynamic sweep and casing treatment in a transonic compressor rotor

Casing treatment and three-dimensional blade design are effective techniques to remedy the deficiency of compressor stability margin, yet their combined effects on compressor performance are seldom studied. With the help of URANS simulations, this paper explored the combined influence of aerodynamic sweep and casing treatment in a transonic compressor rotor. Compared with the configurations of single sweep and single casing treatment, the combined configuration presented an outstanding advantage for improving compressor performance. For compressor overall performance, the stall margin improvement of combined configuration was up to 11.8%, larger than single forward sweep and single casing treatment. Meanwhile, peak efficiency penalty of combined configuration (−1.02%) was significantly lower than that of single casing treatment. Under the effect of casing treatment, the results showed that the pulsating axial velocity could effectively delay the interface of the tip leakage flow and main flow, preventing the overflow of tip leakage flow. The distributions of blockage coefficient and loading coefficient indicated that combined configuration was more effective due to tip unload by casing treatment and blockage resistance ability by forward sweep. Furthermore, the spatial and temporal evolutions of axial velocity at slot opening surface were discussed in detail. Compared with the single casing treatment, higher positive axial velocity excitation and smaller range of negative axial velocity were introduced by combined configuration, which contributed to better stability enhancement.

Novel method for prediction of combinatorial phase-variable gene expression states

Short sequence repeat mediated phase variation results in diverse phenotype presentation in many bacteria including Campylobacter and Neisseria species. Current methods for identifying the expression states of phase-variable genes involve taking a high number of single colonies. This approach is subject to bias, sampling effects and high workloads that reduce the ability to perform intermediary sampling. The use of high concentration colony sweeps provides a work around but reduces the resolution of combinatorial expression profiles (termed phasotypes). A parsimonious approach combining both single colony and sweep data was developed to overcome these limitations. The critical methodological advance is the use of an algorithm that utilises the experimental data from the two sample types and a parsimonious, iterative mathematical analysis that outputs the phasotype distribution with the highest likelihood of underpinning the experimental data sets. The advantages of this unified method are increased resolution and accuracy of gene expression state combinations as compared to conventional single colony sampling, reduced requirement for sampling large numbers of colonies leading to reduced costs, and a higher capacity for collecting samples and replicates.•Inputting of sweep and single colony data into an algorithm for a rapid determination of the combinatorial phase variation states (phasotypes) for repeat-mediated phase-variable bacterial genes•This method reduces the number of single colony samples required to produce accurate estimates of phasotypes•This method will reduce the costs of phasotype analyses and increase potential to analyse more time points or sample sites leading to an improved understanding of how phase variation contributes to bacterial host persistence and the ability to cause disease

The Hard Palate Sweep: a multiplanar 2-dimensional sonographic method for the prenatal detection of cleft palate

Prenatal diagnosis of cleft palate is challenging. Numerous 2-dimensional and 3-dimensional methods have been proposed to assess the integrity of the fetal palate, yet detection rates remain relatively low. We propose the "Hard Palate Sweep," a novel 2-dimensional method that enables clear demonstration of the entire fetal palate throughout pregnancy, in a single sweep, avoiding acoustic shadows cast by surrounding bones. This study aimed to assess the feasibility and performance of the Hard Palate Sweep, performed throughout pregnancy. This was a prospective cross-sectional study performed between 2018 and 2022 in pregnant patients referred for a routine or targeted anomaly scan between 13 and 40 weeks of gestation. The presence or absence of a cleft palate was determined using the "Hard Palate Sweep." This was compared with the postnatal palate integrity assessment. Test feasibility and performance indices, including sensitivity, specificity, and positive and negative predictive values were calculated. Offline clips were reviewed by 2 investigators for the assessment of inter- and intraoperator agreement, using Cohen's kappa formula. The study protocol was approved by the institutional ethics committee. All participating patients were informed and provided consent. A total of 676 fetuses were included in the study. The Hard Palate Sweep was successfully performed in all cases, and 19 cases were determined to have a cleft palate. Of these, 13 cases were excluded because postmortem confirmation was not performed, leaving 663 cases available for analysis. Six cases determined to have a cleft palate were confirmed postnatally. In 655 of 657 cases prenatally determined to have an intact palate, this was confirmed postnatally. In the 2 remaining cases, rare forms of cleft palate were diagnosed postnatally, rendering 75% sensitivity, 100% specificity, 100% positive predictive value, and 99.7% negative predictive value for the Hard Palate Sweep (P<.001). There was complete intra- and interoperator agreement (kappa=1; P<.0001). The Hard Palate Sweep is a feasible and accurate method for prenatally detecting a cleft palate. It was successfully performed in all attempted cases between 13 and 40 weeks of gestation. This method is reproducible, offering high sensitivity and specificity. Implemented routinely, the Hard Palate Sweep is expected to increase the prenatal detection of cleft palate.

Impact of Ignition Assistant on Combustion of Cetane 30 and 35 Jet-Fuel Blends in a Compression-Ignition Engine at Moderate Load and Speed

Abstract This study investigates the use of a commercial-off-the-shelf (COTS) ceramic glow-plug to assist ignition of jet fuel blends with cetane numbers of 30 and 35, below the minimum cetane number of 40 for #2 diesel. Experiments were carried out on a single-cylinder compression-ignition engine operating at 1200 RPM for single and dual-injection (pilot + main) timing sweeps. The COTS glow-plug, termed the ignition assistant, was operated at varying input power levels between 0 and 70 W (stock maximum power input is 30 W) at each SOI. Results demonstrate that the use of an ignition assistant at the higher input powers (50 and 70 W) enables operation over a wider range of SOI timings where more advanced times are limited by high pressure-rise rates and more retarded times are limited by rapidly increasing coefficient of variation of gross indicated mean effective pressure. Use of the ignition assistant enables stable combustion at later injection timings increasing the operable range of SOI timings. For the CN 30 fuel, at earlier injection timings, pressure traces, and heat release analysis demonstrated the advancement of start of combustion and combustion phasing with the ignition assistant on. At retarded injection timings where combustion would not otherwise occur completely for the CN 30 fuel, operating the ignition assistant at the higher powers enabled combustion phasing to be advanced and combustion to be stabilized at conditions where, with the ignition assistant off, misfire (flameout) would occur. Furthermore, the ignition assistant enabled combustion phasing to follow an approximately linear response with respect to SOI timing over a wider range of SOI times.

Digital Fabrication and Reliability Evaluation Method for G-Band TWT Electron Optical System

Terahertz traveling wave tubes (THz-TWTs) electron optical system (EOS) has strict fabrication accuracy requirements. The low reliability of traditional manual assembly always is the direct problem hindering the development of TWT to high frequency, high power, high efficiency, and high reliability. In this article, a digital fabrication and reliability evaluation method for THz-TWTs EOS was presented. First of all, through improving the gun shell structure and sealing molds, developing automatic and semi-automatic assembly methods, writing automatic geometric measure programs, measuring the thermal deformation of cathode and focusing electrode (FE) under working temperature, etc., the implementation of digital fabrication technology was completed, which promoted the fabrication accuracy (1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma \text{)}$</tex-math> </inline-formula> to 3–10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m and 0.05 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> –0.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> . Then, in order to find the tolerance limit to keep the electronic trajectory stable and the balance between design reliability and fabrication reliability, the CST particle solver single and multi-parameter sweep function was used to analyze the EOS of a 0.22 THz-TWT. Based on the digital fabrication technology process capability, 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $</tex-math> </inline-formula> quality management theory, and equal proportion compress single parameter tolerance limit method, we defined four independent sensitive parameters, and calculated the reliability of THz-TWT EOS digital fabrication was not less than 72.47% by MINITAB software. This method can be used as a quantitative calculation of whether the TWT EOS design and fabrication are matched, and give appropriate tolerance and compensation range in the actual TWT fabrication process.

Geometric regularity in webs of non-orb-weaving spiders.

Geometric regularity of spider webs has been intensively studied in orb-weaving spiders, although it is not exclusive of orb weavers. Here, we document the geometrically regular, repetitive elements in the webs of the non-orb-weaving groups Leptonetidae and Telemidae for the first time. Similar to orb weavers, we found areas with regularly spaced parallel lines in the webs of Calileptoneta helferi, Sulcia sp., and cf. Pinelema sp. Furthermore, we provide a detailed account of the regular webs of Ochyrocera (Ochyroceratidae). The sections of the web with regularly disposed parallel lines are built as U-shaped modules reminiscent of orb webs. It has been suggested that the regularly spaced parallel lines in the webs of Ochyroceratidae and Psilodercidae may be produced in a single sweep of their posterior lateral spinnerets, which have regularly spaced aciniform gland spigots, perhaps involving expansion of the spinnerets. To test this hypothesis, we compared the spacing between parallel lines with the spacing between spigots, searched for expansible membranes in the spinnerets, and examined the junctions of regularly spaced lines. The distance between parallel lines was 10-20 times the distance between spigots, and we found no expansible membranes, and the intersection of parallel lines are cemented, which opposes the single sweep hypothesis. Furthermore, we found cues of viscid silk in the parallel lines of the psilodercid Althepus and broadened piriform gland spigots that may be responsible of its production. Finally, we evaluated the presence or absence of geometrically regular web elements across the spider tree of life. We found reports of regular webs in 31 spider families, including 20 families that are not orb weavers and hypothesize that the two basic aspects of regularity (parallel lines spaced at regular intervals, and radial lines spaced at regular angles) probably appeared many times in the evolution of spiders.

Accurate determination of elastic anisotropy to detect internal microstructures using resonant ultrasound spectroscopy

Elastic constants are of great significance, because they are fundamental thermodynamic susceptibilities that connect directly to thermodynamics and electronic structure, as well as to mechanical properties. Resonant ultrasound spectroscopy (RUS) measures non-destructively all fundamental elastic properties by determining the natural frequencies at which a 3D object resonates when is mechanically excited (normal modes). By using an inversion scheme, it is possible to extract the entire elastic tensor of a material with extreme sensitivity in a single frequency sweep using only one, small sample. This makes RUS particularly advantageous to study physical properties of low-symmetry single crystals and textured bulk materials. I will present recent RUS measurement examples of its applications to thermodynamic and materials science problems. I will focus on the effect of texture in elastic constants as a result of mechanical or growth processes and the robustness of results obtained by RUS. In materials such as aluminum that is often considered isotropic but shows clear anisotropy when it is extruded, or 3D printed. Similar but much larger effect is found in additive manufactured stainless steel where the growth process leads to a large anisotropy with a softening of 40%–50% along the build direction.

Multi-sweep 3-dimensional ultrasound is accurate for in vivo muscle volume quantification, expanding use to larger muscles

Muscle volume is an important parameter in analyzing three-dimensional structure of muscle–tendon units. Three-dimensional ultrasound (3DUS) enables excellent quantification of muscle volume in small muscles; however, when a muscle’s cross sectional area is larger than the field of view of the ultrasound transducer at any point along its length, more than one sweep is necessary to reconstruct muscle anatomy. Confounding image registration errors have been reported between multiple sweeps. Here, we detail imaging phantom studies used to (1) define an acquisition protocol that reduces misalignment in 3D reconstruction caused by muscle deformation, and (2) quantify accuracy of 3DUS for measures of volume when phantoms are too large to be fully imaged via a single transducer sweep. Finally, we (3) establish the feasibility of our protocol for in vivo measures by comparing biceps brachii muscle volumes using 3DUS and magnetic resonance imaging (MRI). Phantom studies indicate operator intent to use constant pressure across multiple sweeps effectively mitigates image misalignment, yielding minimal volume error (1.70 ± 1.30%). Intentional application of different pressure between sweeps replicated discontinuity observed previously, leading to larger errors (5.30 ± 0.94%). Based on these findings, we adopted a gel bag standoff and acquired in vivo images of biceps brachii muscles using 3DUS and compared this volume to MRI. We did not observe misalignment errors and there were no significant differences between imaging modalities (-0.71 ± 5.03 %), indicating 3DUS can reliably be used to quantify muscle volume in larger muscles requiring multiple transducer sweeps.

Near infrared voltage sensitive dyes based on chromene electron donors.

Excellent hemicyanine voltage sensitive dyes (VSDs) are available for optical electrophysiology over a wide spectral range out to the far red. Near infrared fluorescent VSDs would be advantageous because they allow deeper light penetration into tissue because of decreased light scattering and also because they can be used in combination with other fluorescent indicators or optogenetic actuators. The usual approach to constructing long wavelength chromophores is to lengthen the π-system; however, this is generally accompanied by a significant decrease in fluorescence quantum efficiency and can also decrease aqueous solubility, making it difficult to deliver the probes to the target tissue. The VSDs developed in our lab are generally composed of an amino-naphthyl electron donor moiety linked to a pyridinium acceptor. Here we show that replacing the naphthalene with chromene induces a 60-80 nm red-shift in the absorption and emission spectra while maintaining the structure at the same size and fluorescence quantum yield at the same level. The voltage sensitivity of these chromene-based VSDs is also comparable to our older VSDs and they display opposite polarity sensitivity when excited at the short and long wavelength edges of the absorbance spectra; thus they can be used in dual wavelength ratio measurements to eliminate artifacts from motion and bleaching. We have tested one of these VSDs in voltage imaging of a whole murine heart at 730 nm, by far the longest wavelength reported in voltage imaging. It resolves action potentials in single sweep scans with 10.1% ΔF/F per action potential. Chromene-based electron donors are likely to find wide applications in generating long wavelength hemicyanines or cyanines. (Supported by NIH grant MH116830. Conflict of Interest statement: LML, CDA, and PY are founders and owners of Potentiometric Probes LLC.)

Effectiveness of multiple versus once-only membrane sweeping at term in preventing prolonged pregnancy: A randomised controlled trial

BackgroundBetween 4 and 18% of pregnancies are prolonged. Prolonged pregnancy is associated with adverse maternal and perinatal outcomes. ObjectivesTo compare the effectiveness of once-only versus multiple (weekly) membrane sweeping in reducing the incidence of prolonged pregnancy. Materials and methods: This randomised controlled trial was conducted over a two-year period, from January 2018 to December 2019, at the Federal Medical Centre and Diete-Koki Memorial Hospital, both in Yenagoa, Bayelsa State, Nigeria. Seven hundred and eighty-six women were equally randomized into two groups: once-only and multiple membrane sweeping, initiated at 39 weeks’ gestational age, but 742 women were included in the analysis. Data obtained was analysed using the Statistical Package for Service Solutions for Windows® version 20, SPSS Inc.; Chicago, USA). Associations between categorical independent and outcome variables were assessed, where applicable, using Chi square test at 95% confidence interval. A P-value of <0.05 was considered statistically significant. ResultsThere were no statistically significant differences between the two groups in terms of time interval between membrane sweeping and delivery (P = 0.85), spontaneous onset of labour (P = 0.21), induction of labour (P = 0.21) and Caesarean section rate (P = 0.68). The maternal complications of vaginal bleeding and pre-labour rupture of membranes following membrane sweeping in the two groups were also comparable (P = 0.45 each). All the women were satisfied and membrane sweeping was acceptable to all of them. ConclusionOnce-only membrane sweeping at 39 weeks’ gestational age is as effective as multiple membrane sweeping for the prevention of prolonged pregnancy. Multiple membrane sweeping does not confer any added advantage/benefit over a single sweep.

Fast Flexible Direct Power Flow for Unbalanced and Balanced Distribution Systems

The study proposes a fast flexible direct power flow solution for radial distribution systems and a fast flexible direct weakly meshed power flow solution for weakly meshed distribution systems. The algorithm is based on the direct forward sweep power flow solution, which is an updated version of the backward/forward sweep solution. The fast flexible direct power flow uses a unique conversion matrix (CM) to rapidly determine the power flow solution. The inverted conversion matrix and its slide-modified matrix are used to solve the power flow problem in a single forward sweep step, which is a novel feature of this work. To ensure the invertibility of the conversion matrix, it is constructed to have a small condition number and a determinant of minus one, and all of its eigenvalues must be equal to that of minus one. Additionally, by modifying the conversion matrix to accommodate the loop branch using the break-point idea, a new weakly meshed conversion matrix (WMCM) is generated with the same following modification as for the radial network and employed in the fast flexible direct weakly meshed power flow (FFDWMPF) solution for the weakly meshed distribution network. The usage of a single matrix in the power flow solution and advanced direct techniques decreases the number of iterations and CPU execution time when MATLAB programming is executed. Furthermore, the proposed method is flexible enough to incorporate any changes in the radial or weakly meshed distribution system just by incorporating the changes in the CM and WMCM for any radial or weakly meshed system. Moreover, the robustness of FFDPF and FFDWMPF is evaluated under various loading scenarios on balanced radial and weakly meshed distribution networks. Finally, to validate the proposed algorithm, the proposed strategy is applied to numerous balanced and unbalanced distribution systems.

Emergence of considerable thermoelectric effect due to the addition of an underlayer in Pt/Co/Pt stack and its application in detecting field free magnetization switching

Application of sufficient lateral current to a heavy metal (HM) can switch the perpendicular magnetization orientation of an adjacent ferromagnetic layer through spin–orbit torques (SOTs). The choice of the HM and its arrangement plays a major role for the SOT induced magnetization switching in magnetic heterostructures. Generally, thin Ta is used as an underlayer to the HM layer for better adhesion and smoothness of the HM layer. Here, we show that Ta addition to the asymmetric stack Pt/Co/Pt gives rise to several compelling effects, viz., thermoelectric effects [particularly, anomalous Nernst effect (ANE)], and enhanced perpendicular magnetic anisotropy which was negligible in a Pt/Co/Pt stack. For this Ta/Pt/Co/Pt stack, the antidamping-SOT values are evaluated after carefully removing the contribution from the ANE and it is found to match the AD-SOT of the Pt/Co/Pt stack. We have observed current-induced field-free magnetization switching Ta/Pt/Co/Pt stack with Co thickness gradient. Furthermore, we have utilized the thermoelectric effects to develop a technique to detect the field-free magnetization switching. This technique detects the second harmonic ANE signal as a reading mechanism. Using ANE symmetry with the applied current, the switching can be detected in a single current sweep which was corroborated to the conventional DC Hall method.