Line Mixing Research Articles

Fault location method for new distribution networks based on waveform matching of time–frequency travelling waves

AbstractSome existing fault location methods for distribution networks rely too much on the local wave head information of the time or frequency domain signals, making it difficult to adapt to the increasingly complex structure and operating conditions of the distribution network after the new energy access. For improvement, the travelling wave (TW) time and frequency ranges that can effectively avoid waveform distortion caused by new energy access are analysed. The one‐to‐one matching relationship between the TW waveforms in these ranges and the fault positions is revealed. A fault TW time–frequency matrix with specific time and frequency windows is constructed, and a new distribution network fault location method is proposed based on the matching technique of waveform features, which realises the accurate fault location by exploring the proportionality between the cumulative trend of the matrix energy amplitude deviation and the fault point position. Simulation test results show that the proposed method is not affected by the complex structure of distribution networks such as new energy access and overhead‐cable line mixing on fault location and flexibly transforms the fault location problem into a time–frequency TW waveform matching problem, which improves the accuracy and robustness of the fault location for new distribution networks to a degree.

Friend or foe: effects of social experience and genetic line on responses of young gilts in a social challenge paired interaction test

The increased focus on group housing of sows in commercial pig production emphasises the importance of saving appropriate gilts which later become sows that are well-adapted to group housing systems. This study aimed to assess the short-term effects of social mixing experience and genetic line on social and exploration responses of young gilts in standardised 3-min social challenge paired interaction tests. The study included 96 gilts, from 26 litters, of two different genetic lines (Swedish Yorkshire and Dutch Yorkshire). These lines were chosen because the dam lines have been selected in group-housed and individual stall systems, respectively, a background which was hypothesised to have modified their social behaviour over time. The gilts were subjected to different early (opportunity to co-mingle with piglets in the neighbouring farrowing pen vs. no opportunity to co-mingle) and late (mixed with unfamiliar piglets at weaning vs. kept with familiar littermates after weaning) social mixing treatments, to test whether the enhanced social experience was beneficial in a socially challenging situation. Paired interaction tests were conducted at 5 and 20 weeks of age, and social and exploration behaviour of the gilts was recorded and analysed. The results showed that Swedish Yorkshire gilts explored the pen fittings more than Dutch Yorkshire gilts during the 5-week test, whereas Dutch Yorkshire gilts explored the pen fittings more than Swedish Yorkshire gilts during the 20-week test. No differences in play behaviour were found during the 5-week test, but in the 20-week test, gilts with early social mixing experience in their farrowing pen showed more locomotor play behaviour than gilts without this experience. Overall, these results suggest that genetic line and early social mixing experience can influence the social and exploration behaviours of young gilts in paired interaction tests. There was no support for the hypothesis that genetic selection in different housing systems has altered social behaviour, but it may have affected the level of exploration behaviour. There was little support for our prediction that early social experience has beneficial effects in a socially challenging situation.

CO[formula omitted] collision-induced line parameters for the [formula omitted] band of 12CH[formula omitted] measured using a hard-collision speed-dependent line shape and the relaxation matrix formalism

Ten high resolution Fourier transform spectra of the pentad region near 3.3μm of methane diluted in carbon dioxide at total pressures up to 800 hPa have been recorded at 296.5(5) K. Including a high resolution spectrum of pure methane at low pressure, these spectra have been analyzed using multi-spectrum fitting techniques. The methane lines were modeled using hard-collision speed-dependent line profiles and line mixing was included in the strongest absorption regions, considering the first order Rosenkranz approximation and the relaxation matrix formalism. CO2 broadening and shift coefficients have been measured, together with the speed dependence of broadening. Results obtained using the two line mixing models are intercompared and compared with previous work.

Measurements and calculations of collisional line parameters for Raman lines of CO perturbed by H2

Close coupling calculations of line shape parameters have been performed for the first pure rotational Raman S0(j=0−3) lines of CO in an H2 bath. The pressure broadening coefficients obtained are in good agreement with the experimental values recently measured at 77, 180 and 298 K by some of us. The quantum dynamical calculations allow us to also determine line shift and Dicke parameters over a wide range of temperatures (20 to 400 K) for these lines. In addition, acquisitions of Raman spectra of the fundamental vibrational Q branch of CO in H2 have been performed allowing the determination of pressure broadening and line mixing coefficients for the first lines of the band at 77, 195 and 298 K. Based on our calculated pure rotational rate constants, we have also deduced pressure broadening and line mixing coefficients for these rovibrational lines. Theoretical values compare reasonably well with the set of experimental data.

Measurements of H2O-O2 line shape parameters and the determination of the intermolecular potential for modified complex Robert-Bonamy calculations

A series of spectra, one pure H2O and four H2O-O2 mixtures, were measured for the ν2 band in the 1200–1950 cm−1 region at room temperature using a single-pass copper cell housed in the Bruker 125HR high-resolution Fourier transform spectrometer (FTS) at Jet Propulsion Laboratory (JPL). All the five spectra were fit simultaneously using a multispectrum non-linear least-squares fitting software, Labfit programme suite, which adopts a speed-dependent Voigt line shape profile using full line mixing taken into account through a relaxation matrix operation. O2-broadened half-width and O2-induced frequency shift coefficients were determined for more than 350 transitions of H2 16O. These data were then checked using the smooth variation and paring rules [Brown et al. J Mol Spectrosc. 2007;246:1-21, Ma et al. Mol Phys. 2011;109:1925-41] and 186 transitions that obey the rules with less than 3% difference were chosen. Using these selected data, Modified Complex Robert-Bonamy calculations were made to determine the intermolecular potential for the H2O-O2 collision system. Some 93 potential were investigated resulting in a final potential (potential 74) that agrees with the selected half-width measurements having an average percent difference of 0.052 and a standard deviation of 5.108% between measurement and calculations.

A modified projection approach to line mixing

This paper presents a simple approach to combine the high-resolution narrowband features of some desired isolated line models together with the far wing behavior of the projection based strong collision (SC) method to line mixing which was introduced by Bulanin, Dokuchaev, Tonkov and Filippov. The method can be viewed in terms of a small diagonal perturbation of the SC relaxation matrix providing the required narrowband accuracy close to the line centers at the same time as the SC line coupling transfer rates are retained and can be optimally scaled to thermalize the radiator after impact. The method can conveniently be placed in the framework of the Boltzmann–Liouville transport equation where a rigorous diagonalization of the line mixing problem requires that molecular phase and velocity changes are assumed to be uncorrelated. A detailed analysis for the general Doppler case is given based on the first order Rosenkranz approximation, and which also provides the possibility to incorporate quadratically speed dependent parameters. Exact solutions for pure pressure broadening and explicit Rosenkranz approximations are given in the case with velocity independent parameters (line frequency, strength, width and shift) which can readily be retrieved from databases such as HITRAN for a large number of species. Numerical examples including comparisons to published measured data are provided in two specific cases concerning the absorption of carbon dioxide in its infrared band of asymmetric stretching, as well as of atmospheric water vapor and oxygen in relevant millimeter bands.

Navigating pharmaceutical product decisions: A comprehensive review

Product management in the pharmaceutical industry is a complex and challenging role that involves overseeing the entire life cycle of a drug product, from development through commercialization and beyond. It requires a deep understanding of the regulatory environment, market dynamics, and patient needs, as well as strong leadership and management skills By classifying product decisions into these categories, businesses can prioritize their efforts and allocate resources effectively. Strategic decisions, for example, may require more resources and involve more stakeholders than operational decisions, but they can also have a greater impact on the success of the product. By making informed product line and product mix decisions, businesses can effectively meet customer needs and grow their market share. By using product portfolio analysis, businesses can make informed decisions about which products to invest in, which to divest or improve, and which new products or markets to pursue. This analysis helps businesses align their product offerings with their overall business strategy and maximize their profitability and growth potential.

The influence of line mixing on the j and k dependencies of halfwidths and temperature exponents in N2-broadening coefficients of CH3F spectral lines

The N2-broadening halfwidths of CH3F in the ν5 and ν6 perpendicular bands have been calculated, along with their temperature exponents. These calculations utilize a modified and refined version of the Robert-Bonamy formalism, developed by the current authors within a semi-classical line shape framework. Extensive comparisons between the predicted halfwidths from the model and experimental measurements at 296 K and 183 K are presented. Our latest model accurately predicts the dependencies of the halfwidths on both the j and k quantum numbers. Furthermore, by extending our calculations to two additional temperatures, namely 240 K and 350 K, the temperature exponent N is determined for various sub-branches. The dependencies of N on j and k are analyzed, and theoretical explanations are provided to elucidate the predicted behaviors of N.

Direct observation of coherence transfer and rotational-to-vibrational energy exchange in optically centrifuged CO2 super-rotors

Optical centrifuges are laser-based molecular traps that can rotationally accelerate molecules to energies rivalling or exceeding molecular bond energies. Here we report time and frequency-resolved ultrafast coherent Raman measurements of optically centrifuged CO2 at 380 Torr spun to energies beyond its bond dissociation energy of 5.5 eV (Jmax = 364, Erot = 6.14 eV, Erot/kB = 71, 200 K). The entire rotational ladder from J = 24 to J = 364 was resolved simultaneously which enabled a more accurate measurement of the centrifugal distortion constants for CO2. Remarkably, coherence transfer was directly observed, and time-resolved, during the field-free relaxation of the trap as rotational energy flowed into bending-mode vibrational excitation. Vibrationally excited CO2 (ν2 > 3) was observed in the time-resolved spectra to populate after 3 mean collision times as a result of rotational-to-vibrational (R-V) energy transfer. Trajectory simulations show an optimal range of J for R-V energy transfer. Dephasing rates for molecules rotating up to 5.5 times during one collision were quantified. Very slow decays of the vibrational hot band rotational coherences suggest that they are sustained by coherence transfer and line mixing.

A Topological Charge Continuously Tunable Orbital Angular Momentum (OAM) Electromagnetic Wave Generation Method Based on Fixed-length Delay Line Mixing Circuit

To overcome the drawback of complex structure and high cost attributed from the utilization of phase shifters to generate OAM in the conventional schemes, this paper proposes a new method for generating OAM based on a fixed delay line. By deriving the proposed system with fixed delay line theoretically, the relationship between the frequency of the input signal on the delay line and the topological charge of the OAM is obtained, and the topological charge of the generated OAM can be controlled by controlling the frequency. Furthermore, this paper proposes a vortex beam pointing control method based on phased array scanning, so as to realize the beam steering of OAM. It is then verified by using electromagnetic simulation, and the simulation results show that the proposed method is feasible. The proposed method not only has the advantages of simple structure and low cost, but also can generate OAM with continuously adjustable topological charge by controlling the frequency, which has the functions of topological charge reconstruction and dynamic adjustment.

Evaluation of spectral line mixing models and the effects on high pressure radiative heat transfer calculations

At higher pressures, the spectral lines in a gas spectrum can become more broadened and shifted due to collisional effects, leading to increased spectral line mixing. In the present study, we have reviewed different line mixing models for modeling the absorption spectra for three gases of CO2, CO, and H2O and applied these models to simulate radiative spectra for pressures within approximately 5–100 bar. The simulated data were compared with the yet-published high-pressure spectral experimental data as well as experimental data published in the literature. It has been found that the empirical “pseudo-Lorentz” line shape model considering the line mixing effects shows the best performance for modeling high-pressure gas spectra for the tested conditions, which is easy to be implemented and relatively accurate, thus is recommended for high-pressure radiative heat transfer calculations in engineering applications. Based on the selected “pseudo-Lorentz” line mixing model, we have constructed a high-pressure absorption coefficients database for CO2, CO, and H2O for pressure ranging from 1 bar to 80 bar. The newly generated database considering the spectral line mixing effects was tested for radiative heat transfer calculations, and the results were compared with the ones without considering the line mixing effects. The significance of ignoring the line mixing effects on radiative heat transfer calculations under different pressures was evaluated with one-dimensional radiative heat transfer benchmark cases. The high-pressure absorption coefficients database is available from the corresponding author upon request.

Temperature-dependent CO2 line mixing models using dual frequency comb absorption and phase spectroscopy up to 25 bar and 1000 K

We perform dual frequency comb laser absorption spectroscopy of CO2 at high pressure and temperature, and use the spectra to test and improve CO2 line mixing models and their temperature dependence. The dual-comb spectrometer spans 6800–7000 cm−1 with 0.0066 cm−1 point spacing, and is coupled to a specialized, high-pressure, high-temperature gas cell providing conditions up to 977 K and 25 bar. We compare our measurements to spectra calculated using an advanced line mixing model for pure CO2 based on the energy-corrected sudden (ECS) approximation. We determine a new set of temperature-dependent ECS model parameters, and show that the new parameters significantly improve the accuracy of the ECS line mixing model over a temperature range spanning 298–977 K. We also compare the measured spectra to a simpler line mixing model developed using the modified exponential gap (MEG) scaling law, and report the temperature and pressure dependence of the MEG model parameters required to scale the model across wide ranges of conditions. Finally, we report high-pressure, ambient-temperature measurements of CO2 spectra in both amplitude (absorption) and phase using the dual-comb spectrometer. We use these measured absorption and phase spectra to assess the performance of the ECS and MEG line mixing models at high densities near room temperature. To the best of our knowledge, these results represent the first study of line mixing using phase spectroscopy. Overall, the results of this study significantly expand line mixing models for CO2 at high pressure and temperature and improve the accuracy and availability of absorption models for harsh conditions encountered in laser-based sensing and planetary science.

Line-shape parameters and line mixing for the low-intensity high-J oxygen transitions

We present the results of investigations of the oxygen B-band R-branch transitions with intensities in the range from 1.5×10−26 to 2.5×10−28 cm−1/(molecule/cm2) and the total angular momentum quantum number for the lower state, J”, up to 38. High resolution CRDS laboratory spectra were fitted with the Voigt profile as well as with advanced line-shape functions consistent with the Hartmann–Tran profile, that is the speed-dependent Voigt profile and speed-dependent Nelkin–Ghatak profile using the multispectrum fitting technique. The line positions, line intensities and other line-shape parameters, together with our previous data, were collated to show trends for the whole R branch. Using the determined frequencies of the B-band transitions, the Dunham fit was performed to obtain spectroscopic parameters for both ground and excited states. Newly recorded spectra at the band head, with the signal-to-noise ratio above 20000, were analyzed with line profiles including also the line mixing. First-order line mixing determined directly from the line shape fitting at relatively low pressure (32 Torr) is in good agreement with values calculated by Sung et al. [1].

A quantum study of argon induced line mixing in ammonia doublets

We present a theoretical study of pressure broadening and coupling coefficients for selected doublets of the ν 4 band of ammomia in argon bath. Generalized spectroscopic kinetic energy dependent cross sections are determined quantum mechanically making use of available NH3-Ar potential energy surfaces. Thermally averaged values at various temperatures are also provided. Results are in overall good agreement with data available in the literature. A further study focusses on the speed dependence of the corresponding line shape parameters. The pressure broadening coefficients are found to have a well marked speed dependence while the intradoublet coupling terms show a small speed dependence at room temperature.

Performance evaluation and optimization of process parameters for a polypropylene unit in naphtha cracker plant using PSO algorithm

The purpose of this case study is to evaluate the performance of assets in oil and gas industry. The study is carried out in polypropylene unit of naphtha cracker plant. The unit produces plastic granules from polypropylene gas and comprises number of subsystems which are complex system in nature. It consists of five important subsystems which are arranged in series and parallel configuration; Pre-contacting pot, In line mixing unit, Flash loop (Heater), Flash drum (Dynamic separator) and Bag filter. The Markov process is used to review the availability of system in the plant with the collected data. In current paper, Chapman-Kolmogorov differential equations are developed with the assistance of mnemonic rule from transition diagram of polypropylene unit. Further, the process parameters are optimised to get optimum value of availability using particle swarm optimisation algorithm tool in MATLAB (R2017a) software. The fruitful results have been observed that maximum availability 95.16 % could be achieved at particle size of 45 and 95.16 % at 70th iteration size. The results of the study are shared with maintenance personnel for setting the maintenance strategy which will helps in production enhance or increasing plant availability.

Quantitative volumetric laser absorption imaging of methane and temperature in flames utilizing line-mixing effects

A mid-infrared volumetric laser absorption imaging technique was developed for quantitative three-dimensional measurements of methane concentration and temperature in combustion flows. The spectroscopic method utilizes temperature-dependent collisional line mixing amongst a cluster of rovibrational transitions of the R(15) maniold of the v3 asymmetric stretch band of methane. Notably, line mixing effects are shown to increase sensitivity of the ratiometric thermometry, and a first-order model enables quantitative inference of species. 3D volumetric imaging is demonstrated experimentally on a methane-oxygen laminar flame doublet (<cm) backlit with tunable radiation from an interband cascade laser near 3.16 μm. 2D images were collected at six different projection angles on a high-speed mid-infrared camera, yielding an aggregate of 27,648 unique lines of sight capturing the scene with a pixel resolution of ∼70 μm. A linear tomographic reconstruction of spectrally-resolved absorbance with a 3D masked Tikhonov regularization method was performed to obtain methane spectra at every grid point, which enables subsequent interpretation of local gas properties. Importantly, this method enables quantitative temperature and species imaging in the fuel decomposition regions of flames.

Line mixing study of carbon monoxide near [formula omitted] broadened by nitrogen, helium, and hydrogen

We present quantitative, broadband absorbance measurements of the fundamental rovibrational band of carbon monoxide (CO) between 1965 and 2230 cm−1 in bath gases of nitrogen (N2), helium (He), and hydrogen (H2). These measurements are then compared to two constructed models capable of reproducing the effects of line mixing present in our measured results. The static cell measurements were taken using a narrow-linewidth, broad-scan external-cavity quantum-cascade laser at pressures of 15–35 atm and temperatures of 293, 453 (CO/H2) and 802 K (CO/N2, CO/He). Our first line mixing approach, based on the modified exponential gap (MEG) law with a fitted inter-branch factor, shows improved agreement with the measured spectra across different pressures and broadening partners relative to purely Lorentzian models. At the elevated temperatures, similar agreement is observed; however, a mismatch is present between extrapolated HITRAN broadening parameters and those observed in the measured spectra. This is likely due to the known deficiency of the single power law over large temperature ranges, and hence a minor scaling of the line-by-line temperature-dependence exponents is incorporated that is supported by previous studies in the literature. Our second, more empirical line mixing approach involves extracting MEG line mixing parameters through a direct fit to the measured spectra. The Direct Fit method bypasses the need for known line shape parameters and produces even stronger agreement with measured data, with a CO/H2 root-mean-square error of 0.4% at the highest-number-density condition of 293 K and 35 atm. The line mixing models presented and discussed will be useful for interpreting future satellite and telescope observations of CO from deeper, higher-number-density layers of exoplanetary gas-giant atmospheres, consisting of mainly H2 and He.

Plasticity for the kin and conspecific preferences in the frog tadpoles (Rana ornativentris).

In vertebrates, little is known of kin recognition systems and their plasticity. Even in well-studied anuran larvae (tadpoles), the determinants and effects of prior experience have not been clarified. This study evaluates the plasticity of kin and conspecific discrimination in tadpoles of the Japanese montane brown frog Rana ornativentris. We raised tadpoles under two different sibship conditions: the pure line, comprising only siblings, and the mixed line, comprising both siblings and non-siblings. The association preference by a subject tadpole to unfamiliar ("stimulus") tadpoles was assessed through binary-choice tests using a 2 × 2 × 2 factorial design among each kinship line (pure and mix), subject ontogeny/size (early stage/small and late-stage/large), and stimuli ontogeny/size. Contrary to our expectations, kin preference was confirmed only in early developmental small tadpoles from mixed line, and only with a small stimulus. Furthermore, tadpoles from mixed line did not exhibit size preference for unrelated conspecifics. These results suggest that different prior associations have modulated kin templates along tadpole ontogeny and that the presence of non-kin would enhance the learning of kin/non-kin. This study provides the first example that plasticity of kin recognition affects not only kin-biased association but also conspecific recognition along ontogeny in tadpoles.

Line coupling and line mixing effects on calculated widths of symmetric-top molecules with the k-degeneracy: A theoretical study of N2-, O2-, and air-broadened lines of CH3I

Calculations of the N2-, O2-, and air-broadened widths, together with their temperature dependence exponents have been made for transitions of CH3I in the ν5 and ν6 bands. The calculations are based on a semi-classical line shape formalism developed by the current authors through modifying and refining the Robert-Bonamy formalism. In recent years, we have applied this formalism for linear molecules, symmetric-top molecules with inversion symmetry, and asymmetric-top molecules. For symmetric-top molecules with the k degeneracy such as CH3I, the formalism has a new feature. In this case, one should consider each of the CH3I transitions labeled by ki or f ≠ 0 as a doublet. Then, one needs to consider the effects of the line mixing process between these two components. Comparisons of our theoretical predictions with some data available demonstrate a very reasonable agreement. Finally we propose new experiments at higher perturber pressures that would enable one to check the theoretically calculated relaxation matrices and to extend the analysis to the inter-doublet mixing effects.

Changes in healthcare spending attributable to obesity and overweight: payer- and service-specific estimates

BackgroundNational efforts to control US healthcare spending are potentially undermined by changes in patient characteristics, and in particular increases in rates of obesity and overweight. The objective of this study was to provide current estimates of the effect of obesity and overweight on healthcare spending overall, by service line and by payer using the National Institutes of Health classifications for BMI.MethodsWe used a quasi-experimental design and analyzed the data using generalized linear models and two-part models to estimate obesity- and overweight-attributable spending. Data was drawn from the 2006 and 2016 Medical Expenditures Panel Survey. We identified individuals in the different BMI classes based on self-reported height and weight.ResultsTotal medical costs attributable to obesity rose to $126 billion per year by 2016, although the marginal cost of obesity declined for all obesity classes. The overall spending increase was due to an increase in obesity prevalence and a population shift to higher obesity classes. Obesity related spending between 2006 and 2016 was relatively constant due to decreases in inpatient spending, which were only partially offset by increases in outpatient spending.ConclusionsWhile total obesity related spending between 2006 and 2016 was relatively constant, by examining the effect of different obesity classes and overweight, it provides insight into spend for each level of obesity and overweight across service line and payer mix. Obesity class 2 and 3 were the main factors driving spending increases, suggesting that persons over BMI of 35 should be the focus for policies focused on controlling spending, such as prevention.