Slope Of Straight Line Research Articles

Manifestation of the normal intensity distribution law (NIDL) in the rovibrational emission spectrum of hydroxyl radical

The latest experimental [Noll et al. Atmos. Chem. Phys. 20, 5269 (2020)] and theoretical [Brooke et al. J. Quant. Spectr. Rad. Transfer 168, 142 (2016)] data on the OH emission intensities are analysed with use of the NIDL. It is found that the calculated intensities of the Δ v > 6 transitions should not be trusted. The analysis of the OH data revealed that the NIDL theory is not applicable to the satellite bands. The effect of small reduced mass previously discovered in H 2 [Ushakov et al. J. Mol. Spectrosc. 399, 111863 (2024)], causing the NIDL straight-line slope to be larger than the one associated with the repulsive branch of the potential, is demonstrated in OH, and the same should be true of all the diatomic hydrides. We performed ab initio calculations of the OH repulsive branch and compared it with the one of Brooke et al. and the other due to Varandas and Voronin [Chem. Phys. 194, 91 (1995)]. We found that the ab initio PEF closely follows the Varandas-Voronin potential in the repulsive region important for calculating the overtone intensities [Medvedev, J. Chem. Phys. 137, 174307 (2012)].

Analyzing impact of network constraints on feasible operation region of the radial distribution networks

Recently, there has been lot of research on finding the feasible operating region (FOR) of the active distribution network (ADN) to provide ancillary services to the transmission grid. The current focus of research is on finding methods that can accurately determine the shape of the FOR and have fast computation time. However, there is little focus on analyzing how network constraints impact the shape of the FOR. This paper attempts to address this issue and provides a mathematical derivation of how network constraints, such as cable loading and voltage limits, would influence FOR. The approach is based on a linear distflow mathematical analysis. The relations derived in the analysis are verified with numerical simulation on radial low-voltage (LV) and medium-voltage (MV) networks. The results show that cable loading constraints cut the FOR in a circular way and voltage constraints cut the FOR with a straight line of slope −ϵ, which is the ratio Rn/Xn of the path from root node to the node under analysis of the radial distribution network.

Mass‐Independent Moisture Percentage Measurements of Flour Using Amplitude Attenuation and Phase Shift Correlation

We performed mass‐independent moisture percentage measurements of flour by using a resonant cavity at 3.9 GHz. The method evaluated the straight line slope that linearly approximates the relationship between the amplitude attenuation and phase shift at a specific frequency for multiple masses of sample. Fifty types of flour with moisture percentage ranging from 9.3% to 17.4% and mass up to 0.3 g were used in this experiment. The standard error of the estimation of the calibration curve for the moisture percentage was 0.42%, which was approximately half of that of the conventional method. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Trajectory and effectiveness of film cooling in endwall crossflow

The crossflow, one of the most important flow structures in the turbine endwall, has significant effects on the endwall film cooling. However, there is a lack of quantitative analysis on it due to the complexity of the endwall flow field. In the current study, a turning channel is utilized to generate the crossflow free from vortex structures. Experiments are conducted and numerical results are utilized to supplement flow-field details. Effects of the momentum ratio (I), crossflow intensity, and main-flow Reynolds number (ReD) are analyzed. Theories of three-dimensional boundary layer flow are introduced to help reveal underlying mechanisms. It is observed that coolant trajectories obey linearity in the cylindrical coordinate. Then, the deflection of coolant can be quantified using the straight-line slope, and I is demonstrated to well scale the coolant migration under the crossflow, which guides predictions on coolant trajectories. Reversely, the disturbance of cooling injections on the crossflow is non-negligible, mainly suppressing the crossflow development. Besides, the crossflow enhances the coolant spreading, and improves the cooling performance. ReD has non-negligible effects on the cooling performance by altering the crossflow profile in the boundary layer. Lower ReD leads to a distorted coolant spatial distribution, resulting in a severer main gas/coolant mixture.

Free-energy differences of OPC-water and SPC/HW-heavy-water models using the Bennett acceptance ratio

Surface tension, vapor density of OPC-water and SPC/HW-heavy-water models have been estimated at low temperatures using the scaled model. The free-energy difference, -ΔF, of n-molecules and (n-1)-molecules plus a free probe has been calculated using the Bennett acceptance ratio with the aid of Monte-Carlo simulations. Our results show that the relation between the free-energy difference divided by kBT and the number of molecules to the power minus one-third is linear for n>6. Consequently, the surface tension can be extracted from the straight line slope, whereas the vapor density can be extracted from the intercept, which is proportional to the logarithmic ratio of liquid density to that of vapor density. By scaling the free-energy differences, for at least three different temperatures, to TCT−1, we estimated the critical temperature and hence the surface tension and the vapor density at a wide range of temperatures. The free-energy differences have been calculated at 240K, 260K, and 280K for OPC-water, and at 260K, 280K, and 300K for the SPC/HW-heavy water model.

(Keynote) Interpretation of Oxygen Reduction Activity Volcano Correlations for MN4 Molecular Catalysts Compared to Those for Metallic Electrodes

A classical well-known reactivity index in electrocatalysis is the binding energy of key intermediates to the active sites. For example, this is well documented for the catalytic activity of metal electrodes for the oxygen reduction reaction (ORR)[1], alloys and metal oxides and less studied for molecular catalysts [2]. The activity at constant potential (log(i)E) plotted versus the M-O2 binding energy has the shape of a volcano. This is well documented in several papers, especially by the group of Norksov for metallic electrodes [1] and can be applied to many electrochemical reactions. This has been extended to MN4 molecular catalysts. In contrast to metallic electrodes MN4 molecular catalysts have discrete energy levels and the active site is the central metal, surrounded by an organic ligand with an MN4 central moiety. Essentially one of the key intermediates is the binding of the reacting O2 molecule to the active sites at the rate determining step as: [MN4]ad + O2(aq) + e- ↔ [RMN4O2 -]ad where MN4 is a surface confined macrocyclic complex or a pyrolyzed catalysts bearing a MN4 active moiety embedded in a graphene or graphitic structure. As the ORR reaction involves the transfer of several electrons ( 2, 2+2 or 4 electrons), several adsorbed intermediates can be involved. If the controlling step is the first step, it is expected that for the binding step when DGad = 0 a maximum activity should be observed and the partial coverage of adsorbed intermediate is = 0.5. On thermodynamic ground this corresponds to a thermoneutral condition for the best catalyst. In this work we have tested this hypothesis by studying ORR in alkaline media using several iron porphyrins and iron phthalocyanines as catalysts immobilized on graphite and carbon nanotubes. The trends in reactivity versus the Fe(III)/(II) redox potential for ORR describe a typical volcano correlation. However if the currents are divided by the θFe(II), the fraction of active sites calculated at E=-0.24 V vs SCE using the Nernst equation, log(i/ θFe(II),)E vs. E°Fe(III)/(II) gives a straight line of slope -0.120V/decade. The maximum corresponds to θFe(II) = 0.5 and occurs at a potential close to that used for comparing the activities. A similar behaviour is observed for the oxidation of hydrazine but the continuation of the straight line is observed at potentials more positive than that of the maximum. Again the maximum is observed at the potential chosen for comparison. Those catalysts having Eº’ Fe(III)/(II) >> θFe(II) higher than -0.56V (for hydrazine oxidation) are in the Fe(III) state as predicted by the Nernst equation. That oxidation state Fe(III) is inactive for both reactions studied as OH- ions are strongly bound to Fe(III), especially in alkaline media. So the falling of the activities in the strong binding side of the volcano can be attributed preferentially to a gradual decline in the number of Fe(II) active sites and not to gradual decrease of the fraction (1-θ ) of empty or available active sites due to occupancy by intermediates. Schmickler and Santos [3] have shown that some volcano correlations for HER on metals that are in an oxidized form, and then inactive for this reason.We conclude that even though there are similarities between the volcano correlations for metallic and molecular catalysts, there some differences in the interpretation of the activity maximum that might not correspond to a thermoneutral condition. Acknowledgements: This work was supported by ANID, Anillo Project ACT 192175 and Fondecyt, Project 1181037

Advances on the Fragmentation-Energy Fan Concept and the Swebrec Function in Modeling Drop Weight Testing

The breakage index equation (BIE), or t10 model from drop weight testing (DWT) data for rocks and ores is used in the design of crushers and mills. Such models are becoming increasingly difficult to visualize as the number of variables increases. The so-called double fan BIE, combined with the Swebrec distribution’s accurate description of the sieving curves, is applied to the modelling of drop-weight test fragmentation. The key parameters are geometric properties visible in the fan plot; slopes of straight lines and their point of convergence. The ability of the double fan BIE to reproduce DWT data had been previously established for 8 rocks with 480 DWT data sets. Here the fidelity of the double fan BIE is further evaluated for 18 new materials, based on 281 data sets. The fidelity of the double fan BIE with three fan lines is on par with the fidelity of the current state-of-the-art models for the new materials. Besides the breakage index equation, the new double fan BIE’s t10 equation produces, without additional parameters or fitted constants, the general breakage surface equation tn for an arbitrary n value as a bonus. The specific sieving curve for any combination of particle size and impact energy is also contained in the same formula. The result is an accurate, compact and transparent model.

Origin of the Maximum in the Activity Volcano Correlations for MN4 Molecular Catalysts Compared to That for Metallic Electrodes

A classical reactivity descriptor in electrocatalysis is the binding energy of key intermediates to the active sites. This is well documented for the catalytic activity of metal electrodes [1], alloys and metal oxides and less studied for molecular catalysts [2]. The activity at constant potential plotted versus these descriptors has the shape of a volcano. This is explained by the classical Sabatier principle, which states that there is an optimum “bond strength” (not too strong, not too weak) establishing the best catalyst for a given reaction. Essentially one of the key intermediates is the binding of the reacting molecule “R” to the active sites at the rate determining step as: [MN4]ad + R(aq) ↔ [RMN4+]ad + e- for oxidations and [MN4]ad + R(aq) + e- ↔ [RMN4-]ad for reductions where MN4 is surface confined macrocyclic complex. If the reaction involves the transfer of several electrons, several adsorbed intermediates can be involved. If the controlling step is the first step, it is expected that for the binding step when Gad = 0 a maximum activity should be observed and the partial coverage of adsorbed intermediate is  = 0.5. This implies an equilibrium constant equal to one for the first step and for the best catalyst. In this work we have tested this hypothesis by studying hydrazine electrooxidation and glutathione in alkaline media using several iron porphyrins and iron phthalocyanines as catalysts immobilized on graphite and carbon nanotubes. Figure A shows the trends in reactivity versus the Fe(III)/(II) redox potential for the oxidation of glutathione describing a typical volcano correlation. However if the currents are divided by the θFe(II), the fraction of active sites calculated at E=-0.3 V vs SCE using the Nernst equation, log(i/ θFe(II),)E vs. E° Fe(III)/(II) gives a straight line of slope -0.140V/decade. The maximum corresponds to θFe(II) = 0.5 and occurs at a potential equal to that used for comparing the activities. A similar behaviour is observed for the oxidation of hydrazine but the continuation of the straight line is observed at potentials more positive than that of the maximum. Again the maximum is observed at the potential chosen for comparison. Those catalysts having Eo’ Fe(III)/(II) >> θFe(II)) than -0.56V are in the Fe(III) state as predicted by the Nernst equation. That oxidation state Fe(III) is inactive for the reaction as OH- ions are strongly bound to Fe(III), especially in alkaline media. So the falling of the activities in the strong binding side of the volcano can be attributed preferentially to a gradual decline in the number of Fe(II) active sites and not to gradual decrease of the fraction (1-θ ) of empty or available active sites due to occupancy by intermediates. This phenomena has also been observed for ORR and for thiols oxidation and seems to be a unique feature of molecular catalysts compared to metal catalysts even though Schmickler and Santos [3] have shown that some volcano correlations for HER on metals that are in an oxidized form, and then inactive for this reason.Acknowledgements: This work was supported by Anillo Project ACT 192175, Fondecyt, Projects 1181037 & 1171408 C.G.C is grateful to a Posdoctoral Fellowship from Dicyt-USACH.

(Invited) Lithium-Ion Transfer Kinetics through Solid Electrolyte Interphase on Graphite Electrodes

For the development of lithium-ion batteries (LIBs) for EV, the internal resistances of LIBs should be required for rapid charge. We have focused on the elucidation of the active sites for lithium-ion intercalation/deintercalation reaction on the graphite negative electrodes. In this study, the influence of the SEI on active sites for lithium-ion intercalation/deintercalation at highly oriented pyrolytic graphite (HOPG) and graphite composite electrode was investigated. We clarified the relation between the standard rate constant (k 0) of [Ru(NH3)6]3+/2+ that is a parameter for edge site of graphite and the interfacial lithium-ion transfer resistance (R ct) in various electrolyte solutions. In plots of k 0 vs. 1/R ct, slopes of straight lines varied with electrolyte solutions. This means that the SEI partly blocked the active site, since the activation energies were not dependent on the SEIs. As a result , we could conclude that the number of the active sites for lithium-ion intercalation/deintercalation strongly depend on the kind of SEIs.

A new test analysis procedure for pressure drawdown test of a horizontal well in an infinite-acting reservoir

This paper develops a new well test analysis procedure of a horizontal well in an infinite-acting reservoir. Hitherto, horizontal well pressure drawdown test analysis during infinite-acting flow was accomplished based on a straight line method obtained from a plot of flowing wellbore pressure versus log of flow time. In that procedure, only limited system characterization was possible. Furthermore, the rigorous type curve matching was resorted to when a straight line did not appear. In the method developed here, a plot of flowing wellbore pressures, pwf, against dimensionless wellbore pressures, pD, is made for analysis. Results show that a straight line relationship exists between the two plotted parameters on a linear paper. The straight line slope across the middle time region can be taken to perform test analysis. From the plot, reservoir pressure, near wellbore permeability, reservoir capacity, fluid mobility and transmissibility can be calculated. Mathematical procedure leading to this method of analysis is based on selection of relevant source and Green’s functions for a horizontal well during infinite-acting flow and purely as a line source. A case pressure test selected for analysis using the method developed here yielded very close reservoir character compared to the reservoir being characterized
 Keywords: Dimensionless pressure, dimensionless derivatives, infinite-acting, horizontal well, early radial flow

Application of Decline Curve Analysis for Estimating Different Properties of Closed Fractured Reservoirs for Vertical Wells

In this paper, decline curve analysis is used for estimating different parameters of bounded naturally fractured reservoirs. This analysis technique is based on rate transient technique, and it is shown that if production rate is plotted against time on a semi-log graph, straight lines are obtained that can be used to determine important parameters of the closed fractured reservoirs. The equations are based on Warren and Root model. The comparison between the results of this technique and those of the conventional methods confirms its high proficiency in transient well testing. It should be noted that in conventional decline curve methods, parameters such as interporosity flow parameter and storage capacity ratio must be first obtained by previous methods like the build-up analysis, but in the proposed method all the main reservoir parameters can be calculated directly, which is one of the advantages of this method. This paper focuses on the interpretation of rate tests, and the starting points and slopes of straight lines are utilized with proper equations to solve directly for various properties. The main important aspect of the presented method is its accuracy since analytical solutions are used for calculating reservoir parameters.

Emergence of a linear slope region of the isotherm in the first-order liquid-expanded–liquid-condensed phase transition in Langmuir monolayers

A nonhorizontal slope in the isotherm has been observed in the two-phase coexisting region of the first-order liquid-expanded (LE)-liquid-condensed (LC) phase transition in Langmuir monolayers for many decades. We show that the simple analysis of a phenomenological Landau free energy involving the coupling-energy contributions of molecular lateral density (ρ) with spontaneous collective chain tilt (θ) and two-dimensional strain (ɛ_{s}) inside the LC domain enables one to understand the origin of a nonhorizontal straight-line slope in the LE-LC phase coexistence region of the isotherm. The presence of ρ-ɛ_{s} coupling must be essential for the appearance of the straight-line shape of a nonhorizontal plateau in the isotherm. Moreover, it is found from the comparison of the two-dimensional contour plots of the free energy that an LE phase may persist significantly even at the later stage of the straight-line regime beyond a transition midpoint surface pressure in the presence of this coupling. The persistence of the LE phase may lead to the delay of transition progress as manifested more clearly by the appearance of a compressibility plateau in the coexistence region that indicates the existence of persistent equilibrium density fluctuations in the monolayer.

Slope Of Straight Line In Ladder: A Learning Trajectory

This research is driven by students’ difficulties in the slope of straight line. The formula of the slope of straight line tends to be taught directly without involving the conceptual basis and the slope of straight line are separated from student’s daily experiences. For this reason, the research was a design research which aims to find out the role of the ladder context in supporting mathematics learning on the slope of straight line topic at the eighth grade. The method has three stages namely preparing for the experiment, the design experiment, and the retrospective analysis. However, in this research, the stage of the design experiment was until the pilot experiment. The techniques of this research used for collecting data were by conducting written tests which included five essay questions, interviews, observation and document reviews. This research involved 12 students who have various capabilities. This research which was conducted produced learning trajectory that consisted of a series of learning in three mathematics activities. Based on the research result, it’s indicated that by using the ladder context plays a significant role in helping students to understand slope of straight line concept and can solve the problems dealing with the slope of straight line in daily life by using PMRI Approach.

Mathematical-physical imperfections in frequently used models for analyzing glass crystallization and glass transition processes

In this paper, the modified Kissinger equation and the Ozava type equation were obtained by using a process of homogenization from dimensional analysis, thus making them correct in relation to the application of a logarithmic function. An equation that holds at maximum reaction rate is applied for the chosen reference heating rate βr and also for a heating rate βi that was used. In that way the modified Kissinger equation lnTmr2Tmi2βiβr=−ER1Tmi+ER1Tmr was obtained. The modified Ozava type equation was obtained in the form.lnβiβr=−mEnR1Tmi+mEnR1Tmrwhere Tmr and Tmi are the temperatures of the maximum obtained with βr and βi respectively. In these equations, free terms are explicitly defined and from their values it is possible to calculate the value of activation energy E, as from the slope of straight lines. The main advantage of the modified equations compared to the original Kissinger equation and the Ozava type equation is not the more accurate value of the activation energy, but the more precise form of the equation.With the goal to overcome all imperfections of the Lasocka equation, we propose the modified relationship Tg = Ag + Bg log(β/βr + 1) between the glass transition temperature Tg and the heating rate β. In this equation, the logarithm is calculated from dimensionless values, where βr is the chosen reference heating rate. In contrast to the original Lasocka equation, the modified Lasocka equation parameters Ag and Bg have the same units. The temperature Tg0 = Ag can be obtained by extrapolation of experimental results to β = 0. This is impossible to get from the original Lasocka equation, but it can be obtained from the modified one.

A modified D-max method to estimate heart rate at a ventilatory threshold during an incremental exercise test.

The purpose of this study was to design a modified D-max method to determine heart rate at a ventilatory threshold (HRVT) and to investigate whether this method would be valid during incremental exercise tests. The HRVT was estimated from a new parameter defined as HR at the maximal difference point between linearly- and quadratically approximated HR trends (modified D-max method). HR and ventilatory gas data for 105 subjects (53 males and 52 females; 38.26 ± 12.06 years; 166.62 ± 8.21 cm; 65.31 ± 11.10 kg) were simultaneously collected during an incremental treadmill test to evaluate the validity of the modified D-max method. Reference HRVTs were manually identified from the ventilatory gas data by an experienced sports physiologist and compared with those estimated by the HR parameter. A strong positive correlation (r = 0.71, p <; 0.01) and a low HR difference of 9.94 ± 7.10 bpm between the reference and estimated HRVTs were obtained. The results indicate that the modified D-max method outperforms the conventional D-max method (r = 0.53, p <; 0.01), the three-piece linear regression lines method (r = 0.42, p <; 0.01), and the parallel straight line slope method (r = 0.57, p <; 0.01). Furthermore, the modified D-max method improves the predictive accuracy of HRVTs by combining its result with subject's age. The combined parameters have a strong positive correlation with the reference HRVTs (r = 0.74, p <; 0.01) and a lower HR difference of 9.40 ± 6.91 bpm. The results suggest that the modified D-max method is highly applicable to predicting HRVTs during incremental exercise tests and also improves HRVT detection accuracy by combining its result with the subject's age.

Synthesis, growth and characterization of amino acid based semiorganic crystal bis-thiourea l-lysine monohydrochloride

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;We report on synthesis, growth and characterization of Bis-thiourea L-lysine monohydrochloride (BTLM) crystal.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Bis-thiourea L-lysine momohydrochloride (BTLM) crystal were grown by solution growth method in the molar ratio 1:1 at room temperature.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Transparent and defect free crystal of BTLM were harvested in the period of 40-45 days with dimension 7mm × 4mm × 2mm. Single crystal XRD analysis revealed that the crystal system belongs to Orthorhombic with cell parameters a= 14.41 Å, b= 5.89 Å and c= 15.52 Å. The sharp and well defined Bragg peaks observed in the powder XRD pattern confirm the crystalline nature of BTLM crystal. The presences of functional groups in the grown crystal BTLM were identified by FT-IR analysis. The fluorescence spectral study was carried out in the range of 280–500 nm. Second harmonic generation (SHG) of powdered BTLM sample was tested using Nd: YAG laser and is found to be 0.55 times that of potassium dihydrogen orthophosphate. The mechanical strength of the BTLM crystal was evaluated and it describes that the Vickers hardness number of BTLM is found to be increase with the applied load. The work hardening co-efficient (n) has been calculated from the slope of straight line between log P and log d. &lt;sup&gt; &lt;/sup&gt;The dielectric study of BTLM was carried out as a function of frequency at different temperature.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;From the result we confirm that the BTLM crystals have good physicochemical properties. So, the grown BTLM crystal was suitable candidate for nonlinear optical applications.&lt;/p&gt;

Spontaneous magnetization reversal caused by magnetic fluctuation in GaMnSb thin films

Time dependences of the magnetic moment m(t) in GaMnSb thin films with MnSb clusters are measured. The m(t) dependences are straightened in semi-logarithmic coordinates m(lnt). The field dependences of magnetic viscosity S(H) corresponding to the slope of straight lines m(lnt) are studied. It is demonstrated that the behaviour of dependences S(H) is governed by the magnetic moment fluctuations of MnSb clusters with lognormal distribution of the magnetic anisotropy energy.

Fast lane detection based on bird’s eye view and improved random sample consensus algorithm

In order to ensure the safety of drivers, Advanced Driving Assistance System (ADAS) has drawn more and more attention. The Lane Departure Warning system is one of the most important parts of ADAS. However, fast and stable lane marking detection is the precondition of it under complex background. In this paper, we proposed a new lane detection method through bird's eye view and improved RANSAC (Random Sample Consensus) algorithm based on the inspiration that extraction of road features from remote sensed images. According to the bird's eye view of the road image, we can recognize the line marking through Progressive Probabilistic Hough transform instead of lane detection. Then, the detected lines are grouped by a new distance-based weighting scheme and we can get the fields of candidate lanes. For each of the fields, lanes are refined through improved RANSAC algorithm and fitted by double models. Hence, the road orientation can be predicted by the curvature and straight line's slope. At last, our experimental results indicated that the lane detection algorithm has good robustness and real-time under various road environment.

Effect of the magnetic anisotropy energy distribution of MnSb clusters on spontaneous magnetization reversal of GaMnSb thin films

Temperature m(T) and time m(t) dependences of the magnetic moment of GaMnSb thin films with MnSb clusters have been measured. The m(t) dependences are straightened in semilogarithmic coordinates m(lnt). The temperature dependences of magnetic viscosity S(T) corresponding to the slope of straight lines m(lnt) have been studied. It have been demonstrated that the behavior of dependences S(T) is governed by the lognormal distribution of the magnetic anisotropy energy of MnSb clusters. It have been found that the behavior of dependences m(T) measured after the films were cooled in zero magnetic field and in magnetic field H = 10 kOe is also governed by the lognormal distribution of the magnetic anisotropy energy of MnSb clusters.

Prediction of free field heave using CW and CH indices

Abstract Prediction of free field heave using CW and CH indices. In order to predict free heave in expansive silty clays two methods were applied: CLOD test and double-swelling methods. In both methods CW and CH indices are required respectively to determine the soil heave. The CW index is determined as a slope of straight line of shrinkage curve obtained with a use of CLOD test. In case of double-swelling method two oedometer tests were carried out to determine CH index: constantvolume and consolidation-swell oedometer tests. Comparison between heave values calculated using CW and CH indexes indicated slight differences.