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This study explores the application of machine learning algorithms—gene expression programming (GEP), adaptive neuro-fuzzy inference system (ANFIS), and artificial neural networks (ANN)—to predict machining responses during the milling of Inconel 690, a superalloy known for its exceptional mechanical properties and oxidation resistance. Machining Inconel 690 presents significant challenges due to its toughness and work-hardening tendencies, which can lead to rapid tool wear and poor surface finish. Traditional optimization methods often rely on empirical models and trial-and-error approaches, which are time-consuming and costly. In contrast, machine learning techniques can effectively model complex, nonlinear relationships between machining parameters and performance outcomes, such as surface roughness, cutting force, and cutting temperature. This study employs statistical metrics, including Root mean square error (RMSE), coefficient of determination (R2), and mean absolute percentage error (MAPE), to determine the predictive performance of the models. The results show that the GEP model achieved an R2 ranging from 0.944 572 to 0.992 999, with an RMSE between 0.015 527% and 0.694 523% and a MAPE ranging from 1.452 397% to 4.947 892%. ANFIS and ANN also demonstrated strong predictive capabilities, although GEP outperformed them. The importance of this study lies in its demonstration of advanced AI techniques as effective tools for optimizing machining processes, ultimately contributing to improved efficiency and quality in manufacturing superalloys. [ABSTRACT FROM AUTHOR]

The electronic absorption spectrum of N,N-dimethylformamide (DMF) is studied in the 45 000-80 000 cm-1 (5.6-9.9 eV) region using synchrotron radiation. The vacuum ultraviolet (VUV) spectrum comprises mostly of Rydberg series of ns, np, and nd types converging to the first two ionization potentials (IPs). Quantum defect values obtained are consistent with excitation of an electron from the highest occupied molecular orbitals localized on nitrogen (4a″) and oxygen (16a′); in addition, the 3s Rydberg transition converging to the third IP (3a″) is observed at 8.95 eV. A reinvestigation of the infrared spectrum of DMF in the 500-4000 cm-1 region with the help of density functional theory (DFT) calculations establishes the planarity of the ground state and leads to revision of several vibrational assignments. Vertical excited state energies and their valence/Rydberg character are predicted using time dependent DFT calculations; excellent correlation is achieved between theoretical results and experimentally observed spectral features. Potential energy curves of the first few excited states give additional insights into the nature of the excited states and their role in photodissociation dynamics. The absorption spectrum of DMF in the region >63 400 cm-1 (7.85 eV) as well as a complete set of spectral assignments in the VUV region (45 000-80 000 cm-1) is reported for the first time. This work represents a comprehensive study of the absorption spectra of DMF in the VUV and infrared regions. [ABSTRACT FROM AUTHOR]

Following the recent identification of ethanethiol in the interstellar medium (ISM) we have carried out Vacuum UltraViolet (VUV) spectroscopy studies of ethanethiol (CH3CH2SH) from 10 K until sublimation in an ultrahigh vacuum chamber simulating astrochemical conditions. These results are compared with those of methanethiol (CH3SH), the lower order thiol also reported to be present in the ISM. VUV spectra recorded at higher temperature reveal conformational changes in the ice and phase transitions whilst evidence for dimer production is also presented. [ABSTRACT FROM AUTHOR]

We report a bandpass ultraviolet photon detector for inverse photoemission spectroscopy with energy resolution of 82 ± 2 meV. The detector (Sr0.7Ca0.3F2/acetone) consists of Sr0.7Ca0.3F2 entrance window with energy transmission cutoff of 9.85 eV and acetone as detection gas with 9.7 eV photoionization threshold. The response function of the detector, measured using synchrotron radiation, has a nearly Gaussian shape. The n = 1 image potential state of Cu(100) and the Fermi edge of silver have been measured to demonstrate the improvement in resolution compared to the CaF2/acetone detector. To show the advantage of improved resolution of the Sr0.7Ca0.3F2/acetone detector, the metal to semiconductor transition in Sn has been studied. The pseudogap in the semiconducting phase of Sn could be identified, which is not possible with the CaF2/acetone detector because of its worse resolution. [ABSTRACT FROM AUTHOR]

A modified design of a CaF2/acetone bandpass photon detector that uses Kr as a filter gas to tune the energy resolution is presented. Our design combines two standard single window detector tubes to build the Kr filter gas chamber. Synchrotron radiation has been used to determine the energy resolution of the detector, as a function of Kr pressure. The improvement in the detector energy resolution by 250 meV compared to the CaF2/acetone detector is better than that reported earlier. Substantial variation in the shape of the CaF2/acetone detector response functions is observed for different acetone pressure (≤3 mbar), and anode voltage (≤800 V). Our analysis reveals that the changes in the shape of the detector response function are associated to different regions of the detector operation. [ABSTRACT FROM AUTHOR]

This paper reports on an ultrasonic waveguide sensor for liquid level measurements using three guided wave modes simultaneously. The fundamental wave modes longitudinal L(0,1), torsional T(0,1), and flexural F(1,1) were simultaneously transmitted/received in a thin stainless steel wire-like waveguide using a standard shear wave transducer when oriented at an angle of 45° to the axis of the waveguide. Experiments were conducted in non-viscous fluid (water) and viscous fluid (castor oil). It was observed that the flexural F(1,1) wave mode showed a change in both time of flight (due to the change in velocity and dispersion effects) and amplitude (due to leakage) for different levels (0-9 cm) of immersion of the waveguide in a fluid medium. For the same level of immersion in the fluid, the L(0,1) and the T(0,1) modes show only a relatively smaller change in amplitude and no change in time of flight. The experimental results were validated using finite element model studies. The measured change in time of flight and/or the shift in central frequency of F(1,1) was related to the liquid level measurements. Multiple trials show repeatability with a maximum error of 2.5% in level measurement. Also, by monitoring all three wave modes simultaneously, a more versatile and redundancy in measurements of the fluid level inside critical enclosures of processing industries can be achieved by compensating for changes in the fluid temperature using one mode, while the level is measured using another. This ultrasonic waveguide technique will be helpful for remote measurements in physically inaccessible areas in hostile environments.