Constant Values Research Articles

A systematic approach for synthesizing 3D-printable all-dielectric devices

We present a systematic approach for synthesizing 3D-printable all-dielectric devices. Inverse design approaches yield, in many cases, configurations with a continuous range of dielectric constant values. However, 3D printer resins usually provide a very limited set of such values; commonly, a single resin and air are the only available materials. We propose a methodology for transforming a device with a continuous range of material properties to a manufacturable one, while preserving the device’s performance as close as possible to the continuous case. We develop an algorithm that takes the continuous range of dielectric constant profile as input and generates a binary and connected device that can be 3D-printed using a single resin. Our methodology advances state-of-the-art algorithms by using manufacturable configurations of prescribed local air/resin composition to realize each designed dielectric material instead of being limited to a predetermined shape. The additional degrees of freedom provided by our approach may be particularly useful in devices of conformal complex-shaped dielectric constant profiles. We demonstrate the proposed methodology by designing a 3D-printable wide-angle refraction metagrating with performance very close to the inversely designed device of a continuous dielectric constant profile. The approach can be adapted to accommodate three-dimensional devices and other applications.

Spiral-Hole Moderation Enhances Borehole-Image Interpretation in Carbonates

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 23355, “Spiral-Hole Moderation Enhances High-Resolution Borehole-Image Interpretation Across Fractured Carbonate Reservoirs,” by Alawi Altarouti, Abdullah Alotaibi, SPE, and Prudencio Guerreiro, Saudi Aramco, et al. The paper has not been peer reviewed. Copyright 2024 International Petroleum Technology Conference. _ Dynamic phenomena while drilling such as borehole spiraling or corkscrewing can create a physical imprint on the borehole surface, which masks fine features of imaging. During a drilling campaign in a carbonate reservoir using logging-while-drilling (LWD) technology, corkscrewing affected ultrahigh-resolution borehole image quality severely. The complete paper presents the methodology and results of the bit-design test to mitigate the presence of borehole spiraling, resulting in a significantly improved ultrahigh-resolution borehole image. Introduction A recent drilling campaign in an offshore carbonate reservoir in horizontal wellbores required the use of resistivity-based LWD ultrahigh-resolution images (UHRI) with rotary steerable systems (RSS) to evaluate the presence of natural fractures. During LWD logging of the targeted carbonate reservoirs using water-based mud, borehole artifacts were observed as spirals around the borehole. These artifacts had an adverse effect on the borehole-log analysis and interpretation and evaluation of natural fractures, particularly partial fractures that could be masked. In some cases, it was estimated that more than 30% of the fractures could not be identified. Comparing log results of LWD with historical wireline logs run in the same formation and similar well profiles across the field indicated that the artificial spirals only were present when using LWD tools to image the wells. More commonly, borehole spiraling has been observed on a macro scale, wherein the spiraling can be measured in feet. The spiraling in this well was detected only with high-resolution LWD laterolog imaging and affected fracture interpretation. The spiraling remained undetected, below resolution, on the conventional LWD measurements. Methodology Technical Analysis. Spiraling occurred primarily while drilling across relatively soft formations with bulk density values of approximately 2.15 to 2.20 g/cm3. Intervals with higher densities were affected to a lesser extent or not at all. The spiraling occurred in a consistent manner. While downhole shocks and vibration were considered to be a possible cause of spiraling, the periodic occurrence of the traces did not align with the chaotic nature of shocks and vibration. The shape of the traces did not match with possible lateral or axial motions of the bottomhole assemblies (BHAs); however, these spirals may have been caused and aggravated by low-frequency torsional vibrations. Although the level of the stick and slips was found to be medium to high throughout the runs, no evidence supported this theory. The wide range of downhole rotational speed fluctuations could not explain the perfect shape of the spirals. It also was observed that the distance between each trace or spiral correlated with the rate of penetration (ROP) and had constant values in similar ROP ranges. It could have been suspected that the spiraling did not occur across the hard formations because of lower ROP and the overlapping between them as the result of slow drilling. However, the ROP reduced marginally compared with the drilling in the soft formations (approximately only 10%). Thus, ROP was considered one of the lowest-affecting parameters to mitigate spiraling effects.

Layer-by-layer growth, apparent instability, and mound coarsening in thin film deposition controlled by thermally activated surface diffusion

Thin film deposition from vapor with adsorbate diffusion and Ehrlich-Schwoebel (ES) barriers at step edges is studied by kinetic Monte Carlo (KMC) simulations and scaling approaches. Mound coarsening with slope selection is shown at the largest thicknesses, where roughness (W) and correlation length (ξ) scale in time with exponents β≈n≈0.25, consistently with theoretical works but contrasting with previous simulations that systematically showed temperature-dependent exponents. At a given film thickness, we show that the mounded morphology is independent of the ES barrier, so that interlayer transport is suppressed, while the temperature increase of W and ξ is consistent with intralayer transport limited by adatom detachment from flat terrace borders. Initial layer-by-layer (LBL) growth occurs above a characteristic temperature that increases with the activation energies of terrace diffusion and of ES barrier, but weakly depends on the external flux. Subsequently, as the surface roughness is near the atom/molecule size, there is rapid roughening where, counterintuitively, larger effective growth exponents (β>0.5, suggesting unstable growth) are correlated with longer LBL regimes. Similar LBL-rough transitions were reported in organic film deposition and the model application to diindenoperylene films suggests a large ES barrier ∼0.4eV. In the mound coarsening regime, W/ξ and θ1/2/Wξ converge to constant values dependent on surface diffusion coefficients (θ is the film thickness). This convergence suggests mound coarsening with slope selection in SnTe films whose effective β is anomalously large, showing how film morphology can be interpreted beyond exponent measurements.

Capillary Electrophoresis-Frontal Analysis (CE-FA) and Molecular Docking Studies on the Albumin-Binding Properties of Dopamine and Serotonin.

Dopamine and serotonin are neurotransmitters that are crucial for numerous physiological processes, including mood regulation, reward, and motor function. Dysregulation of these neurotransmitters is associated with various neuropsychiatric disorders. Albumin in plasma modulates the bioavailability of drugs and free concentrations of bioactive constituents. This study aimed to characterize the interactions of dopamine and serotonin with bovine serum albumin. Capillary electrophoresis in the frontal analysis mode was utilized as an effective method to assess dopamine-bovine serum albumin and serotonin-bovine serum albumin affinity. The free neurotransmitter plateaus were distinctly separated from the bovine serum albumin-neurotransmitter complex plateaus. Free dopamine and serotonin concentrations were determined by monitoring the heights of their respective plateaus. In contrast, the bound concentrations were calculated from the difference between the total and free plateau heights. Dopamine and serotonin were found to bind to bovine serum albumin at independent sites with binding constant values of 1.90×103 and 2.90×103L/mol, respectively. Additionally, an in silico molecular docking approach revealed the binding sites for dopamine and serotonin near the glutamic acid-291 and serine-428 residues of bovine serum albumin, respectively.

Characterization of the Dust and Sodium Tails of Comet C/2020 F3 (NEOWISE) from Parker Solar Probe and Amateur Observations

Comet C/2020 F3 (NEOWISE) reached perihelion on 2020 July 3 at 0.29 au and exhibited a highly structured dust tail. Using a simplified Finson–Probstein model, structures such as striae, observed in the tail in images obtained by the Parker Solar Probe spacecraft and amateur observers, are characterized in this work and parameterized in terms of dust ejection dates and dust β values. Other dust tail features are syndynic bands: bright, curved regions of the dust tail that lie within constant values of dust β. This study is the first in-depth analysis of these structures. Analysis revealed that the dust β distribution in the tail was approximately bimodal, corresponding to the two syndynic bands observed in the tail. The region between these bands, bounded by the β = 0.82 ± 0.02 and β = 1.20 ± 0.02 syndynes, appeared to have a reduced dust population, suggesting that dust grains of these β values were produced at a much lower rate. The alignments of the striae in the tail were measured and compared to the interleaved striae seen in C/2006 P1. C/2020 F3 was found to have no interleaved striae, which is possibly due to the timing of the comet’s heliospheric current sheet crossing, not coinciding with, the main period of dust ejection.

Studies of the Novel Bioactive Acridine‐1,3‐thiazolidin‐4‐one Derivatives With Human Serum Albumin Using Fluorescence Spectroscopy and Molecular Modelling

ABSTRACTIn this study, we employ spectroscopic, thermodynamic and molecular docking approaches to identify the mechanism by which thiazolidinone derivatives 4a–4d bind with human serum albumin. It has been suggested that the affinity of the interaction of derivatives 4a–4d with HSA is within the optimal range necessary for the transportation and distribution of compounds within the organism. The binding constant values for the derivative/HSA complexes were found to be 0.03–5.87 × 105 M−1. Both ΔH0 and ΔS0 values were negative, which indicates that binding occurs mainly through van der Waals forces and hydrogen bonding. The negative values calculated for ΔG0 indicate that the binding of derivatives 4a–4d with HSA is a spontaneous process. Our study also reveals that derivatives 4a–4d bind to the subdomain IB (Site III) of HSA and that this binding alters the conformation and thermodynamic stability of HSA. Molecular docking simulations suggest that the main binding forces are van der Waals interactions, hydrophobic interactions and hydrogen bonds. The studied compounds showed weak DPPH‐scavenging activity at all of the tested concentrations. The results suggest that compound 4b with a phenyl substituent at the nitrogen atom of the 1,3‐thiazolidin‐4‐one moiety can be considered the most potent antioxidant in the series.

Correlation and application of thermal expansion coefficient/elastic modulus for co-sintered composite cermet/ceramic materials

Deformation and stress concentration appearing during high-temperature sintering process significantly affect production quality of solid oxide cell (SOC), due to mismatched mechanical and thermophysical properties of the sintered electrode and electrolyte. In this study, a coarse-grained molecular dynamics (CG-MD) method is developed to evaluate and correlate coefficient of thermal expansion (CTE) and elastic modulus during the entire co-sintering process (including temperature-increasing, −insulation, and -decreasing stages). It is revealed that, in the sintered porous cermet electrode, CTE primarily exhibits an increasing trend until temperature-decreasing stage. Compared to the constant values commonly applied in the literature, the elastic modulus experiences a decay trend with a reduction of 32.14 % in the porous electrode and 9.68 % reduction in the dense electrolyte. The obtained CTE and elastic modulus are correlated with the sintering parameters and further applied to a macroscopical model for predicting overall sintering warpage and stress in a co-sintered SOC half-cell composed of a thick porous electrode and a thin dense layer. The varied CTE is identified as the main factor influencing warpage deformation, while the elastic modulus as a more significant impact on the von Mises stress during the co-sintering of the half-cell. Analysis is further conducted by orthogonal testing method for sintering temperature, sintering time, material content and diameter ratio of the porous cermet nanoparticles, aiming to optimize the varied CTE and elastic modulus, particularly during the temperature-insulation process. Subsequently, the optimized properties are implemented, and it is found that, after sintering insulation for 120 min, the maximum warpage displacement is about 7.34 mm, which represents a decrease of approximately 14.11 %; while the von Mises stress is observed to be 379.24 MPa, which indicates a reduction of around 37.33 % compared with the predictions by the constant properties.

Designing ZrO2-blended nanocomposite MIM capacitors for future OFET applications and their characterizations

Organic field-effect transistors (OFETs) have been exploited as sensors for a variety of applications due to their excellent advantages over diodes and other electronic devices. Capacitors are one of the key components of the OFET designs that consist of a dielectric layer sandwiched between two parallel metal plates. The dielectric layer should be thin and/or have a high k constant value to achieve a high capacitance value (Ci, areal capacitance), so more charge carriers can be accumulated at the interface between the dielectric and the organic semiconductor, for OFETs to operate under low voltage (< 3 V). In this study, high-k nanocomposites (NCs) of ZrO2 metal oxide ceramic nanoparticles (NPs) in varying concentrations blended in two different polymer matrixes, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cyanoethyl cellulose (CEC) have been utilised as the dielectric layer in metal-insulator-metal (MIM) capacitors. The physical and electrical properties of fabricated MIM capacitors were evaluated. The measured areal capacitance, Ci, values demonstrated a gradual rise with increasing ZrO2 metal oxide content in both polymer matrixes. ZrO2-PVDF-HFP-based capacitors exhibited a two-fold increase in Ci, 91.86 ± 6.1 nF/cm2 (a 140 % increase) for 10 wt % NP content. Similarly, areal capacitance values of 76 ± 3.03 nF/cm2 (a 45 % rise) was measured on MIMs using CZ10 dielectric layer. High average dielectric constant (k) values of 28.61 and 35.68 for CZ5 and PZ5, respectively) were obtained. As expected, leakage current density increased for higher NP % in polymer matrixes. Nevertheless, all MIMs yielded average leakage current density < 1.75 × 10−6 (A/cm2) at 2 V. Therefore, the reported nanocomposites are suitable dielectric layers for OFETs and as platforms for gas, chemical and photoactivated sensing devices.

Fluorescent sensing copolymers: Synthesis, nanofiber fabrication and application in picric acid sensors

Increasing attention has been paid to the detection of explosives due to the occurrence of terrorist attacks around the world. Here, we used free radical polymerization to develop two different types of fluorescent copolymers for use in detecting picric acid. One exhibits aggregation-caused quenching (ACQ) and is called PNNS [poly (N-isopropyl acrylamide-co-N-hydroxymethyl acrylamide -co-styrene-pyrene), poly (NIPAAm-co-NMA-co-St-Py)]. The other possesses aggregation-induced emission (AIE) properties and is called PNNP [poly (N-isopropyl acrylamide-co-N-hydroxymethyl acrylamide-co-2-(1,2,3,4,5-pentaphenyl-1H-silol-1-yloxy) ethyl methacrylate), poly (NIPAAm-co-NMA-co-PPS-HEMA)]. Nanofibrous thin films of these copolymers were obtained by electrospinning. Upon interaction with picric acid, the fluorescence intensity of each copolymer was quenched due to photo-induced electron transfer (PET). The average diameters of PNNS and PNNP nanofibers were 179 ± 28 nm and 235 ± 143 nm, respectively. Sensing performance was evaluated by Stern-Volmer analysis. The Stern-Volmer constant (Ksv) values for PNNS and PNNP nanofibers were 0.012 μΜ−1 and 0.119 μΜ−1, respectively. Since the aggregated state of PNNP nanofibrous thin films can increase dramatically, the AIE property of this material provides a large dynamic range. Finally, the reusability of water- and methanol-washed nanofiber thin films was tested, revealing that the nanofiber sensors were reusable for detecting picric acid.

Effect of grinding methods on slime dissociation characteristics and flotation kinetics of coking coal

Despite extensive research on the connection between coal flotation kinetics and particle size, little is known about the shape effect. To fill this gap, this study aims not only to explore dissociation characteristics and particle shape properties resulting from the grinding of coking coal in a planetary ball mill (PBM) and a vertical shaft impact crusher (VSIC) but also to investigate their effects on flotation kinetics. Moreover, for the first time in the literature, shape, kinetic rate constant, and bubble loading capacity (hydrophobicity) properties of coking coal products ground in two different mills were compared by shape characterization, flotation kinetics, and single bubble loading tests, respectively. The findings are: (1) Compared to PBM, VSIC produced rounder-shaped particles with a better communition selectivity, (2) Since PBM's flotation rate constant values (Km) were higher than VSIC's, the particles produced by the PBM exhibit a favorable aspect ratio for faster flotation.

Estimation of multicomponent reactions’ yields from networks of mechanistic steps

This work describes estimation of yields of complex, multicomponent reactions (MCRs) based on the modeled networks of mechanistic steps spanning both the main reaction pathway as well as immediate and downstream side reactions. Because experimental values of the kinetic rate constants for individual mechanistic transforms are extremely sparse, these constants are approximated here using Mayr’s nucleophilicity and electrophilicity parameters fine-tuned by correction terms grounded in linear free-energy relationships. With this formalism, the model trained on the mechanistic networks of only 20 – but mechanistically- and yield-diverse MCRs – transfers well to newly discovered MCRs that are based on markedly different mechanisms and types of individual mechanistic transforms. These results suggest that mechanistic-level approach to yield estimation may be a useful alternative to models that are derived from full-reaction data and lack information about yield-lowering side reactions.

Elastic waves scattering by the schoty in microscopic system 2D

We investigate the scattering phenomenon at the non-uniform crystalline surface. Localized modes emerge in its vicinity due to the inhomogeneity-induced breakdown of translation symmetry. The phonon scattering mechanisms at the inhomogeneity are investigated by means of the Newton equation and matching approach. Numerical findings are presented across a wide range of scattering energies, together with the estimation of the transmission and reflection probabilities and the elastic wave average transmittance across the defect. This shows how the softening, homogeneity, and hardening characteristics of the perturbed defect vary in their scattering spectra. Fano resonances in the spectra are caused by the coherent coupling between the localized modes created by the defect and the propagating mode of the ideal waveguide. For a variety of values of the elastic constants in the bulk and inhomogeneous domain, a comprehensive explanation is given. The features of the system model and the stimulating dimensionless frequencies are used to calculate the conductance of the system.

Adoption of Multiphase and Variable Flux Motors in Automotive Applications

This paper investigates the incorporation of multiphase (MP) and variable flux (VF) permanent magnet motors to electric vehicles (EVs). A literature review is carried out first, which covers the characteristics, benefits and challenges of both motor configurations. MP motors, with their increased phase number, offer enhanced fault tolerance, reduced torque ripple, and improved efficiency, among other benefits. VF technology allows for dynamic adjustment of the magnetic field, optimising motor performance across various operating conditions. By integrating these technologies, this study aims to harness the benefits of both MP configurations and VF capabilities. For this reason, the Finite Element Method (FEM) is used with three-phase, MP, VF, and VF-MP motors. The main contribution is that both technologies have been implemented in a single motor to evaluate and quantify their impact together, obtaining higher torque and constant power values, lower torque ripples, and higher efficiencies in the whole working range.

Crystallographic Profiling, Core-Shell Electronic Configurations, and Investigations of Frequency-Dependent Dielectric Characteristics of Sb2O3-V2O5 Micro Ceramics

A series of V2-xSb2xO5-δ (Sb-V-O) ceramic powder samples with molar concentrations ranging from 0.05 to 0.08 were synthesized using a solid-state reaction method. Crystallographic analysis conducted through Rietveld refinement indicates that at a molar fraction of x=0.05, the orthorhombic V₂O₅ phase is observed. Conversely, at molar concentrations of x=0.06, 0.07, and 0.08, the orthorhombic phase of V2O5 and the tetragonal phase of SbVO4 are present simultaneously. X-ray photoelectron spectroscopy (XPS) was employed to ascertain the elemental oxidation states, revealing the presence of V5+, V4+, Sb3+ ions, and Sb0 metal atoms, along with O1s photoelectron peaks. The photoluminescence (PL) emission spectrum suggests transitions from a shallow donor level to the valance band. The room temperature AC conductivity and dielectric property results reveal a systematic decrease in the dielectric constant. The AC conductivity experimental data was accurately modeled using the Almond-West formalism, yielding high R2 values (0.9968–0.9986) and low chi-square errors (1.157×10⁻11–9.42×10⁻12) obtaining hopping frequency values for each composition (x = 0.05–0.08). AC conductivity (σac) decreased from 5.08×10⁻⁴ S/m to 2.40×10⁻⁴ S/m at 10 MHz, while DC conductivity (σdc) dropped from 7.22×10⁻⁵ S/m to 1.55×10⁻⁵ S/m. This reduction in conductivity is attributed to structural changes from Sb³⁺ substitution, which disrupts polaronic conduction by reducing the number of available O2⁻ ions and promoting SbVO₄ phase formation, hindering charge transport. The Sb₂O₃-V₂O₅ ceramics exhibit promising potential for energy storage applications, particularly in capacitors requiring high dielectric constants at low frequencies. At lower frequencies, grain boundaries inhibit conduction, enhancing dielectric constant values; at elevated frequencies, grain conduction predominates, lowering dielectric constant in accordance with Koop’s phenomenological theory, favoring applications in multi-layer ceramic capacitors. A notably higher dielectric loss factor (εr'') at low frequencies (10 Hz–1 kHz) indicates lossy behavior, beneficial for microwave absorption, while its stabilization above 10 kHz suggests minimal energy dissipation, ideal for high-frequency electronic and dielectric devices.

High Resolution Rovibrational Spectroscopy of the ν6 and ν3 + ν7 Bands of H2CCCH.

The molecular ion H2CCCH+ has been further investigated in a 4 K cryogenic ion trap instrument employing the leak-out spectroscopy (LOS) method. Transitions within two perpendicular bands, the fundamental ν6 (antisymmetric H-C-H stretch) and the combination band ν3 + ν7 (C≡C stretch and CH2 rock), have been measured in high resolution for the first time. The spectral analysis was aided by high level quantum chemical calculations and by our previous study of the parallel ν1 and ν3 + ν5 bands [Silva, W. G. D. P. ; Mol. Phys. 2023, e2296613]. The novel results presented here have allowed for a seventy-fold improvement on the accuracy of the value of the A0 rotational constant of this near-prolate asymmetric top.

Normalization of the Constant score in the Spanish population

BackgroundNormal Constant score values for healthy shoulders can vary between regions and change over the years as life expectancy increases and physical condition improves. Spain’s population is one of the healthiest and has one of the highest life expectancies in the world, which could be reflected in its normal Constant score values. The purpose of this study is finding the normal Constant score values in the Spanish population. MethodsCross-sectional study completed between 2023-2024, including subjects older than 18 years of age without any previous or ongoing shoulder condition. Constant score was taken for both shoulders of every subject. A stratified analysis of total and subtotal scores was performed, grouping subjects by age and sex. ResultsA total of 505 subjects and 1010 shoulders were included, with a mean age of 52.3 ± 18.6 years and men/women ratio of 39.6%/60.4%. Five groups were formed according to age: 18-30 years-old (18.4%), 31-45 years-old (16.4%), 46-60 years-old (29.8%), 61-75 years-old (23.7%), and over 75 years-old (11.7%). Each of these groups were divided in two groups according to sex, making a total of 10 groups. Mean Constant score was 88.9 ± 10.9, the group of men between 18-30 years-old having the highest mean score (99.2 ± 3.0) and the group of women over 75 years-old having the lowest mean score (75.3 ± 8.8). A statistically significant inverse correlation was found between total score and age (r = -.47, p < .001). Total score was also significantly lower in the women (84.5 ± 8.2 vs 92.6 ± 8.5, p < .001). The decrease in mobility (r = -.45, p < .001) and strength (r = -.40, p < .001), and the difference in strength between the men and the women (10.6 ± 3.8 vs 6.0 ± 2.0, p < .001) were the main underlying causes of the difference in total Constant score between groups. ConclusionNormal values of the Spanish version of the Constant score in healthy shoulders of the Spanish population decrease with age and are lower in women, the main differences being found in shoulder mobility and strength. Global scores found in this population are higher than those previously published for English, American, and Swiss populations.

A hysteretic water retention model incorporating the soil deformability and its application to rainfall-induced landslides

Traditional water retention models often overlook the dynamic interplay between soil structure and moisture content, leading to inaccurate predictions of unsaturated soil behaviors. In this research, based on laboratory data, van Genuchten’s soil water characteristic (van Genuchten, 1980) is modified to establish two bounding surfaces that define the permissible range of soil states in terms of the void ratio (e), suction (s), and degree of saturation (Sl). Considering a bounding surface technique, the model effectively captures hysteresis in the soil water retention behavior, encompassing main curves and scanning paths. This approach presumesthat within the permissible range of soil states, which is included between two main surfaces, the derivative of the degree of saturation by void ratio and suction relieson the soil state’s proximity to the main bounding surface. This hypothesis guarantees that the wetting–drying or compressing-swelling scanning curves transit smoothly toward their corresponding main surfaces. The derived equations for Sl are integrated into closed forms, allowing all scanning curves to be distinguished by varying values of the integration constant. Model necessitates the determination of two parameters (b and β) related to the slope and intercept of the linear line interpolating experiments in the ln(s)-ln(eSl/s) plane, which can be defined based on at least a single wetting–drying test. The model predictions are validated against various data sets, including sands and clayey soils, published in the literature. This validation demonstrates the model’s ability to reflect the behavior observed in experimental tests accurately. This new technique offers a significant advantage in the simplicity of parameter determination. Finally, this hysteretic water retention procedure is implemented into a finite element program (Code_Bright), and its performance is evaluated by simulating the behavior of a representative slope subjected to rainfall conditions.

High precision measurement of the Tc99β spectrum

Highly precise measurements of the Tc99β spectrum were performed in two laboratories using metallic magnetic calorimeters. Independent sample preparations, evaluation methods, and analyses yielded consistent results and the spectrum could be measured down to less than 1keV. Consistent β spectra were also obtained via cross evaluations of the experimental data sets. An additional independent measurement with silicon detectors in a 4π configuration confirms the spectrum shape above 25keV. Detailed theoretical calculations were performed using the nuclear shell model and including atomic effects. The spectrum shape was found to be sensitive to the effective value of the axial-vector coupling constant. Combining measurements and predictions, we extracted Qβ=295.82(16)keV, gVeff=0.376(5), and gAeff=0.574(36), which seems to solve an inconsistency of the quenched coupling constants between first and higher forbidden nonunique transitions. Furthermore, we derived the mean energy of the β spectrum, E¯β=98.51(23)keV, logf=−0.47660(22), and logft=12.3478(23). Published by the American Physical Society 2024

Role of [formula omitted] gravity with class one space-time in constructing new spherically symmetric stellar solutions

This paper aims to investigate the possibility of generating exact solutions for appropriate anisotropic spherically symmetric systems in F(Q,T) gravity where Q and T are non-metricity and the trace of the energy-momentum tensor respectively. These solutions involve embedding a spherically symmetric static metric into a five-dimensional pseudo-Euclidean space. To solve Einstein's field equations and ensure that the solution is free of center singularities, a physically plausible selection of the metric coefficient grr is used. With the help of the Karmarkar condition, we compute the gtt component of the metric tensor using the metric coefficient grr. At the boundary of the compact star, we match interior spacetime with the exterior spacetime to find the values of unknown constants. To make the solution match the measured mass and radius, we have tuned up the solution for compact star PSRJ1614-220. The behavior of the solution has been thoroughly examined for the same star. By examining the necessary physical characteristics, such as energy conditions, causality condition, hydrostatic equilibrium, pressure-density ratio, Herera Cracking criterion, etc., the physical acceptability of the model in the context of F(Q,T) has been investigated. It is observed that the present solution allows viable modeling of stellar objects in F(Q,T) gravity.

PENGUJIAN CUTTER ENDMILL HSS DIAMETER 12 MM DENGAN PEMOTONGAN DEPT OF CUT TERHADAP BAJA AMUTIT DI MESIN MILLING LAGUN FU 100 (LFR 25)

This study aims to analyze the relationship between machining parameters and tool wear (flank wear) in the milling process of amutite steel (SKS3) using a 12 mm diameter High-Speed Steel (HSS) endmill cutter. The machining parameters studied included cutting speed (Vc = 14 m/min and 18 m/min), feed rate (F = 30 mm/min and 75 mm/min), and depth of cut (Doc = 0.5, 1, 1.5, 2 and 2.5 mm). The linear regression method was used to build a mathematical model relating these parameters to tool wear. Experimental data were obtained through a series of machining tests with predetermined parameter variations. The regression analysis results showed that tool wear or flank wear (Vb) was significantly affected by cutting speed (Vc), feed rate (F), and depth of cut (Doc), with constant and exponent values obtained through logarithmic transformation and regression analysis. The regression model obtained has a good level of accuracy in predicting tool wear, although there is a difference between the theoretical and actual Vb values. This discrepancy may be caused by factors not measured in the experiment, such as variations in workpiece material or environmental conditions. This research also provides that the 12 mm diameter HSS endmill cutter is proven to be capable of carrying out the depth-of-cutting process on amutite steel material in the Lagun FU 100 milling machine with the specified depth-of-cut.