Use Of Scaling Factors Research Articles

Directional Amplification at Rock Sites in Fault Damage Zones

Site effects refer to the modification of ground shaking caused by the local geological conditions that can result in the strong amplification of ground motion. The best-known cause for site effects is the presence of superficial soft soil deposits, which are considered in seismic design codes of many countries through the use of scaling factors. Rock sites are assumed to show no local site amplification. However, even at rock sites, seismic waves can be locally amplified at frequencies of engineering interest, with larger motion along one site-specific azimuth on the horizontal plane (the so called “directional site resonance or amplification”). These effects have been related to the presence of large-scale open cracks or microcracks in different geological environments (faults, landslides, volcanic areas) everywhere with a common signature: maximum amplification occurs transverse to the predominant fracture strike. In this paper, we summarize our main results obtained in the last decade with regard to several fault zones with different kinematics, where ground motion is polarized (and amplified) perpendicularly to the predominant fracture field as an effect of the stiffness anisotropy. In order to give a further constraint, we also show some cases where the directional amplification effects were compared with the S-wave splitting analysis method.

The search for a band of a defect predicted above 4000 cm-1 in diamond through infrared vibrational spectra: a quantum mechanical investigation.

For many years, the atomic structures of several defects in diamond with high wavenumber (>4000 cm-1), including "amber centers", H1b, and H1c, have been investigated, but a conclusive explanation is still lacking. In this paper, we propose a novel model for the N-H bond under repulsion, with an expected vibrational frequency exceeding 4000 cm-1. Additionally, potential defects called NVH4 are proposed to investigate their correlation with these defects. Three NVH4 defects are considered, denoting a charge of e = +1, e = 0, and e = -1 for NVH4+, NVH04, and NVH4-, respectively. Subsequently, the geometry, charge, energy, band structure, and spectroscopic characterization of the three defects NVH4+, NVH04, and NVH4- are analysed. Then, the calculated harmonic modes of N3VH defects are used as a benchmark for studying NVH4. The simulations indicate that, with the use of scaling factors, the highest NVH4+ harmonic infrared peaks are 4072 cm-1, 4096 cm-1, and 4095 cm-1 with PBE, PBE0, and B3LYP, respectively, along with a calculated anharmonic infrared peak at 4146 cm-1. These calculated characteristic peaks closely match those observed in "amber centers" (4065 cm-1 and 4165 cm-1). However, based on the additional simulated anharmonic infrared peak at 3792 cm-1, NVH4+ cannot be assigned to the 4165 cm-1 band. It is possible to assign the 4065 cm-1 band to NVH4+; even though it can remain stable in diamond at 1973 K, establishing and measuring this benchmark could be challenging. Although NVH4+ is uncertain as a structure in "amber centers", a model of the N-H bond under repulsion stretching is proposed, which can generate a vibrational frequency surpassing 4000 cm-1. It may provide a useful avenue for investigating high wavenumber defect structures in diamond.

Aspects of Continuous User Identification Based on Free Texts and Hidden Monitoring

This paper investigates some specific features of continuous user identification based on hidden monitoring of keystroke dynamics when creating a free text. Our analysis of static identification approaches does not reveal any significant limitations on their application to continuous identification. The main feature of continuous identification is the method for collecting dynamic information about key presses and the correction of templates of registered users. The effectiveness of including additional classification features in recognition algorithms, e.g., those associated with the frequency of letters in texts, is demonstrated. A software application is developed to collect and analyze keystroke rhythm samples of users. Research in the domain of users with good computer skills shows quite satisfactory user recognition accuracy (87% on average). Moreover, the accuracy does not depend on the metric distance selected for recognition and improves with the use of scaling factors for letter frequency.

Development of UV Spectrophotometric Procedures for Determination of Amlodipine and Celecoxib in Formulation: Use of Scaling Factor to Improve the Sensitivity

FDA has recently approved a new fixed-dose combination of amlodipine besylate (AMD) and celecoxib (COX) for the treatment of hypertension and osteoarthritis. No analytical method has been reported for analysis of these two analytes so far. Hence, to monitor the quality and quantity in the formulation of AMD and COX a simple, accurate, precise, economical, and eco-friendly spectroscopic analytical method has been established. The first method involves the determination of AMD and COX by the first derivative UV spectroscopic method with scaling factor 10. However, the second method was based on the direct measurement of UV absorbance of AMD at 364.3 nm and ratio first derivative UV spectroscopic method for COX. Both methods showed good linearity in the range of 5 to 40 μg/ml for COX, whereas AMD showed linearity in the range of 0.5 to 10 μg/ml in first derivative method with scaling factor 10 and 1 to 10 μg/ml in the second method with good correlation coefficient (R2 > 0.998). Both the methods were validated for LOD, LOQ, accuracy, precision, recovery studies, and stability as per the ICH guidelines, and the validated results were well within the acceptable range. Both the methods were successfully utilized for the determination of AMD and COX in the presence of each other in the formulation, and statistically compared between the proposed methods. Therefore, the proposed procedures can be utilized for regular quality control studies.

The Impact of Scaling Factor Variability on Risk-Relevant Pharmacokinetic Outcomes in Children: A Case Study Using Bromodichloromethane (BDCM).

Biotransformation rates extrapolated from in vitro data are used increasingly in human physiologically based pharmacokinetic (PBPK) models. This practice requires use of scaling factors, including microsomal content (mg of microsomal protein/g liver, MPPGL), enzyme specific content, and liver mass as a fraction of body weight (FVL). Previous analyses indicated that scaling factor variability impacts pharmacokinetic (PK) outcomes used in adult population dose-response studies. This analysis was extended to pediatric populations because large inter-individual differences in enzyme ontogeny likely would further contribute to scaling factor variability. An adult bromodichloromethane (BDCM) model (Kenyon, E. M., Eklund, C., Leavens, T. L., and Pegram, R. A. (2016a). Development and application of a human PBPK model for bromodichloromethane (BDCM) to investigate impacts of multi-route exposure. J. Appl. Toxicol. 36, 1095-1111) was re-parameterized for neonates, infants, and toddlers. Monte Carlo analysis was used to assess the impact of pediatric scaling factor variation on model-derived PK outcomes compared with adult findings. BDCM dose metrics were estimated following a single 0.05-liter drink of water or a 20-min bath, under typical (5 µg/l) and plausible higher (20 µg/l) BDCM concentrations. MPPGL, CYP2E1, and FVL values reflected the distribution of reported pediatric population values. The impact of scaling factor variability on PK outcome variation was different for each exposure scenario, but similar for each BDCM water concentration. The higher CYP2E1 expression variability during early childhood was reflected in greater variability in predicted PK outcomes in younger age groups, particularly for the oral exposure route. Sensitivity analysis confirmed the most influential parameter for this variability was CYP2E1, particularly in neonates. These findings demonstrate the importance of age-dependent scaling factor variation used for in vitro to in vivo extrapolation of biotransformation rates.

Evaluation of a pneumatic surgical robot with dynamic force feedback.

Robot-assisted surgery is limited by the lack of haptic feedback and increased operating times. Force scaling adjusts feedback transmitted to the operator through the use of scaling factors. Herein, we investigate how force scaling affects forces exerted in robotic surgery during simple and complex tasks, using a pneumatic surgical robot, IBIS VI. Secondary objectives were to test the effects of force scaling on operating time, depth of needle insertion and user satisfaction. Two novice males performed simple (modified block transfer) and complex (needle insertion) tasks under four scaling factors: 0.0, 0.5, 1.0 and 2.0. Single-blind experiments were repeated five times, with alternating scaling factors in random order. Increasing the scaling factor from 0.0 to 2.0 reduces forces in block transfer (p = 0.04). All feedback conditions reduce forces in needle insertion compared to baseline (0.5: p < 0.001, 1.0: p = 0.001, 2.0: p = 0.001). Time to complete block transfer is shorter for scaling factor 0.5 (p = 0.02), but not for 1.0 (p = 0.05) or 2.0 (p = 0.48), compared to baseline. Depth of needle insertion decreases consistently with incremental scaling factors (p < 0.001). Further reductions are observed upon augmenting feedback (0.5-2.0: p = 0.02). User satisfaction in block transfer is highest for intermediate scaling factors (0.0-1.0: p = 0.01), but no change is observed in needle insertion (p = 0.99). Increments in scaling factor reduce forces exerted, particularly in tasks requiring precision. Depth of needle insertion follows a similar pattern, but operating time and user satisfaction are improved by intermediate scaling factors. In summary, dynamic adjustment of force feedback can improve operative outcomes and advance surgical automation.

Anisotropic Cosmological Models with Two Fluids

Anisotropic dark energy cosmological models have been constructed in a Bianchi V space-time, with the energy momentum tensor consisting of two noninteracting fluids, namely, bulk viscous fluid and dark energy fluid. Two different models are constructed based on the power law cosmology and de Sitter universe. The constructed model was also embedded with different pressure gradients along different spatial directions. The variable equation of state (EoS) parameter and skewness parameters for both models are obtained and analysed. The physical properties of the models obtained with the use of scale factors of power law and de Sitter law are also presented.

Improving on equilibrium isotropic nuclear shielding constants

AbstractIsotropic nuclear shielding constants at the equilibrium molecular structure σeq and zero‐point vibrational corrections (ZPVCs) to σeq are evaluated using the B3LYP/aug‐cc‐pVTZ level of theory, as well as the KT2/aug‐cc‐pVTZ level of theory. Various scaling factors and systematic corrections are obtained by linear regression to experimental shielding constants. Comparisons of the scaled and systematically corrected equilibrium and vibrationally averaged shielding constants reveal that, at the 99% confidence level, the ZPVCs via second‐order perturbation theory do not improve the agreement of B3LYP/aug‐cc‐pVTZ and KT2/aug‐cc‐pVTZ calculated shielding constants with experiment. This holds true when the same analysis is applied to CCSD(T)/aug‐cc‐pCV[TQ]Z calculated σeq of Teale et al. [Journal of Chemical Physics 2013, 138, 024111]. In addition, at the 99% confidence level, B3LYP/aug‐cc‐pVTZ and KT2/aug‐cc‐pVTZ scaled and systematically corrected shielding constants are found to be statistically no different from CCSD(T)/aug‐cc‐pCV[TQ]Z calculated σeq. The use of scaling factors and systematic corrections could thus provide a cheaper but yet reasonably accurate alternative for the study of nuclear shielding constants of larger systems.

Procedure to estimate ammonia loss after N fertiliser application to moist soil

Decision support systems (DSS) that provide advice on best N fertiliser management practice ideally need to assess the effect that fertiliser type, rate and management have on N loss. Currently only nitrate leaching and denitrification losses can be assessed in Australian DSS that use output from the Agriculture Production Simulator (APSIM). This paper describes a simple spreadsheet-based model for estimating NH3 loss from urea, urea ammonium nitrate and ammonium sulfate that can be used in conjunction or independent of current DSS. The use of scaling factors that reduce NH3 emission on the basis of factors known to be key determinants of NH3 loss, including type of fertiliser used, rate of fertiliser applied, management of fertiliser, rainfall and crop development was found to account for 85% of the variance between predicted and observed values when tested against 40 case studies. The model also had good predictive power with a root mean square error (RMSE) equivalent to 4.8% of N applied.

One-dimensional time-domain finite-element modelling of nonlinear wave propagation for non-destructive evaluation

This one-dimensional time-domain finite-element model achieves accurate quantitative modelling of ultrasonic wave propagation in multi-layered structures. First, a sinusoidal wave toneburst is sent into a single layer of material exhibiting inherent material nonlinearity characterised by the nonlinear parameter β and thick enough for the toneburst received in through transmission to be resolved. The signal processing protocol that yields the theoretically correct quantitative value of β involves measuring the received toneburst for several propagation distances as well as the use of scaling factors taking into account the fast Fourier transform implementation, input signal windowing and material damping. Using that model configuration, model parameters (element size, time step, frequency step, input pressure, etc.) are then optimised and chosen quantitatively to generate accurate results. Finally, these model parameters are used for cases of interest where the configuration is not such that the exact β value can be obtained – e.g. thinner sample, pulse-echo etc. but where confidence in the results remains. This quantitative model that can be used for multi-layered structures provides a tangible resource useful to NDE engineers: a new prediction tool expected to enable them to choose the experimental set-up, driving frequency and post-processing method that would optimise kissing bond detection capability.

Sizing of Reverse Micelles in Microemulsions using NMR Measurements of Diffusion

This paper reports the size of reverse micelles (RMs) in AOT/octane/H(2)O and CTAB/hexanol/H(2)O microemulsions using magnetic resonance (MR) pulsed field gradient (PFG) measurements of diffusion. Diffusion data were measured using the pulsed gradient stimulated echo (PGSTE) experiment for surfactant molecules residing in the RM interface. Inverse Laplace transformation of these data generated diffusion coefficients for the RMs, which were converted into hydrodynamic radii using the Stokes-Einstein relation. This technique is complementary to those previously used to size RMs, such as dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS), but also offers several advantages, which are discussed. RM sizes, determined using the PGSTE method, in the AOT (sodium bis(2-ethylhexyl) sulfosuccinate) and CTAB (cetyltrimethylammonium bromide) microemulsions were compared with previous DLS and SAXS data, showing good agreement. Methods for determining number distributions from the PGSTE data, through the use of scaling factors, were investigated.

Measuring Particle Size Distribution Using Laser Diffraction

Methods to predict soil hydraulic properties frequently re- quire information on the particle size distribution (PSD). The objectives of this study were to investigate various protocols for rapidly measuring PSD using the laser diffraction technique, compare the obtained PSD with those determined using the traditional hydrometer-and-sieves method (HSM), and assess the accuracy of soil hydraulic properties pre- dicted from the measured PSD. Ten soil samples encompassing a wide textural range were analyzed using the l-1SM and 3 different laser dif- fraction methods (LDM 1, LDM2. and (DM3). In (DM1, the soil sam- ple was thoroughly mixed before analysis. In LDM2, the sand fraction was sieved out and analyzed separately from the silt-clay fraction. l.DM3 was similar to LDM2 except that the silt-clay fraction was diluted so that a large sample volume could he used while maintaining an acceptable level of obscuration. (DM'_' and (DM3 improved the agreement be- tween the PSD with the IISM in comparison to LDM1, without the need of altering the Mie theory parameters or the use of scaling factors. Moreover, a reasonable prediction of measured saturated hydraulic con- ductivity and water retention curve was achieved when using the PSD from LDM2 and (DM3, in conjunction with bulk density information.

Raman and Infrared Fingerprint Spectroscopy of Peroxide-Based Explosives

A comparative study of the vibrational spectroscopy of peroxide-based explosives is presented. Triacetone triperoxide (TATP) and hexamethyl-enetriperoxide-diamine (HMTD), now commonly used by terrorists, are examined as well as other peroxide-ring structures: DADP (diacetone diperoxide); TPTP [3,3,6,6,9,9-Hexaethyl-1,2,4,5,7,8-hexaoxo-nonane (tripentanone triperoxide)]; DCypDp {6,7,13,14-Tetraoxadispiro [4.2.4.2]tetradecane (dicyclopentanone diperoxide)}; TCypDp {6,7,15,16,22,23-Hexaoxatrispiro[4.2.4.2.4.2] henicosane (tricyclopentanone triperoxide)}; DCyhDp {7,8,15,16-tetraoxadispiro [5.2.5.2] hexadecane (dicyclohexanone diperoxide)}; and TCyhTp {7,8,14,15,21,22-hexaoxatrispiro [5.2.5.2.5.2] tetracosane (tricyclohexanone triperoxide)}. Both Raman and infrared (IR) spectra were measured and compared to theoretical calculations. The calculated spectra were obtained by calculation of the harmonic frequencies of the studied compounds, at the density functional theory (DFT) B3LYP/cc-pVDZ level of theory, and by the use of scaling factors. It is found that the vibrational features related to the peroxide bonds are strongly mixed. As a result, the spectrum is congested and highly sensitive to minor changes in the molecule.

Anharmonic Force Fields of Naphthalene-h 8 and Naphthalene-d 8

The cubic and the quartic semidiagonal anharmonic force fields of naphthalene-h8 and -d8 are obtained using density functional theory (DFT) with the B9-71 functional and a triple-zeta plus double polarization (TZ2P) basis set. The fundamental frequencies computed by second-order vibrational perturbation theory are in very good agreement with the experimental data, with a mean absolute deviation (MAD) of 4 cm(-1) for C(10)H(8) and 6 cm(-1) for C(10)D(8). Some of the fundamental frequencies have been reassigned on the basis of the present results. Only CH stretchings seem to be significantly affected by Fermi resonances, with two shifts larger than 10 cm(-1). Calculated infrared harmonic intensities reproduce the experimental data within 15%, with the exception of CH stretchings affected by a larger error. Scale factors from C(10)H(8) have been tested by deriving the fundamental frequencies of C(10)D(8) from the theoretical harmonic ones. These fundamentals are in nice agreement with those obtained from the C(10)D(8) anharmonic force field. These results support the use of scale factors to calculate the vibration spectra of larger polycyclic aromatic hydrocarbons of great astrophysical interest.

Scale factors as effective parameters for correcting nonempirical force fields

Sources of uncertainties that arise in the search for scale factors used to systematically correct theoretical quantum-mechanical force fields in the harmonic approximation are considered. The special features of various approaches to the traditional procedure for scaling according to Pulay are analyzed. It is suggested that scale factors be determined as quotients obtained by dividing the diagonal elements of the approximation to the exact matrix of force constants by their quantum-mechanical analogues. Using this approach obviates the necessity of solving the inverse problem. Perturbation theory is used to show that, when molecular geometric parameters and scale factors are varied jointly, an exact correlation can appear, which substantiates the effective character of force field corrections with the use of scale factors. The procedure for the scaling of generalized quantum-mechanical force fields based on the transition from the normal-coordinate to natural-coordinate representation is considered.

BFW: A Density Functional for Transition Metal Clusters

Ionization potentials (IPs) or electron affinities (EAs) for transition metal clusters are an important property that can be used to identify and differentiate between clusters. Accurate calculation of these values is therefore vital. Previous attempts using a variety of DFT models have correctly predicted trends, but have relied on the use of scaling factors to compare to experimental IPs. In this paper, we introduce a new density functional (BFW) that is explicitly designed to yield accurate, absolute IPs for transition metal clusters. This paper presents the numerical results for a selection of transition metal clusters and their carbides, nitrides, and oxides for which experimental IPs are known. When tested on transition metal clusters, the BFW functional is found to be significantly more accurate than B3LYP and B3PW91.

New initialization methods for discrete coefficient FIR filter design with coefficient scaling and the use of scale factor in the design process

The initialization of filter coefficients in discrete-coefficient finite-impulse-response (FIR) filter design (with coefficient scaling) using coefficient-value-assignment-based optimization techniques is considered. A common weakness of existing initialization measures, a total-square-error (TSE) measure and a maximum-error (ME) measure, is described. New TSE and ME measures that overcome the weakness are introduced. As opposed to the current knowledge, it is revealed that TSE and ME measures do not necessarily provide different initial coefficient set information and that the initial coefficient set information by the ME measure is not unique in general. On a parallel track, the treatment of coefficient scaling in the optimization process is considered. The closed-form expression of the objective function normalized peak ripple magnitude (NPRM), which was defined implicitly in the literature, is given. In contrast to existing methods, the computation of NPRM accordingly does not require a scale-factor parameter independent of filter coefficients although coefficient scaling persists. Then, TSE and ME measures become practically equivalent (although, in general, they indicate different initial scale factors) since an explicit scale factor parameter is no longer needed.

About the benzotriazole tautomerism: an ab initio study

The tautomeric equilibrium of benzotriazole was investigated using Hartree–Fock (HF), MP2, B3LYP and coupled cluster methodologies with a series of basis set. The HF and MP2 results present a clear preference for the 1H and 2H tautomers, respectively, while with B3LYP and coupled cluster both structures have a very similar energy. The inclusion of zero point energy was proved to be necessary when using B3LYP and coupled cluster methods, leading to a preference for the 1H tautomer. The geometric parameters obtained with MP2 and B3LYP using aug-cc-pVTZ basis set are very similar to experimental data of 1H. The frequencies also provided a great concordance with experimental data with the correct use of scale factor. Dipole moment and rotational constants were also analysed.

Assessing the dose-dependency of allometric scaling performance using physiologically based pharmacokinetic modeling

The performance of allometric scaling of dose as a power of body weight under a variety of extrapolation conditions with respect to species, route, exposure intensity, and mechanism/mode of action, remains untested in many cases. In this paper, animal–human internal dose ratio comparisons have been developed for 12 chemicals (benzene, carbon tetrachloride, chloroform, diisopropylfluorophosphate, ethanol, ethylene oxide, methylene chloride, methylmercury, styrene, tetrachloroethene, trichloroethene, and vinyl chloride). This group of predominantly volatile and lipophilic chemicals was selected on the basis that their kinetics have been well-studied and can be predicted in mice, rats, and humans using physiologically based pharmacokinetic (PBPK) models. PBPK model predictions were compared to the allometric scaling predictions for interspecies extrapolation. Recommendations for the application of the allometric scaling are made with reference to internal dose measure (mode of action) and concentration level. The results of this assessment generally support the use of scaling factors recommended in the published literature, which includes scaling factors of 1.0 for risk assessments in which toxicity is attributed to the parent chemical or stable metabolite, and −0.75 for dose–response assessments in which toxicity is attributed to the formation of a reactive metabolite from an inhaled compound. A scaling factor of 0.75 is recommended for dose–response assessments of orally administered compounds in which toxicity is attributed to the parent chemical or stable metabolite and 1.0 for risk assessments in which toxicity is attributed to the formation of a reactive metabolite from a compound administered by the oral route. A dose-dependency in the results suggests that the scaling factors appropriate at high exposures may differ from those at low exposures, primarily due to the impact of saturable metabolism.

Analysis of vibrational spectra of naphthalene, deuterionaphthalenes, and chromium (η6-naphthalene)tricarbonyl based on density functional calculations

The vibrational frequencies and force constants for naphthalene (C10H8), 1,4,5,8- and 2,3,6,7-tetradeuterionaphthalenes (C10H4D4), octadeuterionaphthalene (C10D8), and chromium (η6-naphthalene)tricarbonyl were calculated by the DFT method using the PBE approximation in extended and split bases. The results calculated without the use of scaling factors are in good agreement with the IR and Raman experimental data. All vibrational frequencies for the free ligand and π-complex molecules were assigned. The influence of coordination to the transition metal on the frequencies and force field of the naphthalene molecule (both for the free ring and the ring coordinated to the transition metal) was discussed.