Set Of Prediction Equations Research Articles

Estimating the validity of Tanaka-Johnston and Moyer's analysis of a Saudi sample.

Accurate estimation of unerupted permanent canines and premolars is a crucial step for effective orthodontic treatment planning during mixed dentition. This study aimed to evaluate the validity of Moyers' charts and the Tanaka-Johnston equation in predicting tooth sizes in a sample of the Madina population in Saudi Arabia and propose a new regression equation. Dental casts from 219 subjects (113 males and 106 females) were analyzed. Actual mesiodistal tooth widths were measured using digital calipers with an accuracy of 0.01 mm. Moyers' and Tanaka-Johnston predictions were compared with actual measurements, and a new set of prediction equations was developed. Tanaka-Johnston predictions consistently overestimated the actual measurements, exhibiting a difference of 1.20 mm for maxillary canines and premolars and a difference of 1.25 mm for mandibular teeth. The Moyers chart showed gender-specific variations with males aligning with the 50th percentile and females aligning with the 65th percentile for upper arches and the 50th percentile for lower arches. Newly derived linear regression equations were established for predicting the sum of upper and lower canines and premolars for the Madina population. The study highlights limitations in the Moyers and Tanaka-Johnston methods used for the current sample as both methods overestimated tooth sizes. New regression equations were developed to offer a more accurate approach for predicting tooth sizes for the study sample.

A unified tensile constitutive model for mono/hybrid fibre-reinforced ultra-high-performance concrete (UHPC)

Providing a representative and reliable tensile constitutive model for ultra-high-performance concrete (UHPC) has been challenging in the past due to the absence of standardised test methods. In this paper, the authors have proposed a unified constitutive model calibrated to the most commonly used types of steel fibres within the practical range of fibre content. While the novel model serves as the core, a comprehensive experimental program and results are pivotal for validating the model’s effectiveness. In pursuit of this, the recently approved AASHTO standard test method was employed to offer standardised and comprehensive experimental insights into the direct tensile behaviour of mono/hybrid fibre-reinforced UHPC. A set of predictive equations, derived either empirically or from simple mechanics, to predict the key parameters defining the mechanical constitutive law of UHPC material subjected to uniaxial tension are introduced based on experimental findings. The proposed predictive equations and constitutive model exhibited robust predictions of tensile behaviour, aligning well with both the test results and additional independently tested UHPC specimens.

Post-fire mechanical response of high strength steels

A test programme looking into the residual mechanical properties of fire exposed high strength steels (HSS) has been presented in this study. Accurate predictions of the residual mechanical properties of fire exposed structures are necessary to develop a proper strategy for their restoration. A test programme was conducted to investigate the post-fire residual material properties of thermomechanical control processed cold-formed HSS tubular members. The nominal yield strengths of tubular members were 900 and 960 MPa. The tubular members investigated in this study were made up of square, rectangular and circular hollow sections. The tubular members were heated inside a gas furnace, where the fire exposure generally followed the heating part of the ISO-834 standard fire [1] curve. The tubular members were exposed to 4 fire exposure temperatures, i.e. 300°C, 550°C, 750°C and 900°C, followed by their natural air-cooling inside the furnace. Subsequently, at ambient temperature, a total of 80 post-fire coupons was extracted from these ISO-834 standard fire exposed tubular members. The post-fire coupons were extracted from the flat, corner and curved regions of the fire exposed tubular members. The post-fire material properties and their respective residual factors were determined using the static stress–strain curves, which were obtained from their corresponding test stress–strain curves. New prediction equations are proposed for the post-fire residual material properties using the post-fire residual factors obtained in this test programme as well as available data in the literature for steel grades more than or equal to S690. It should be noted that two sets of prediction equations are proposed in this study, first, for the flat region, and second, for the corner and curved regions. The proposed prediction equations for the post-fire residual material properties of the flat region are valid for both hot-rolled and cold-formed HSS with nominal yield strengths ranged from 690 to 1070 MPa. Whereas, the proposed prediction equations for the post-fire residual material properties of the corner and curved regions are valid for cold-formed HSS with yield strengths ranged from 900 to 1200 MPa.

Effects of pre-fatigue damage on mechanical properties of Q690 high-strength steel

Abstract This paper investigates the residual strength of Q690 high-strength steel previously damaged by fatigue. Pre-fatigue damage was induced by subjecting the specimens to nine different loading cycles without causing fracturing under three initial cyclic loadings, and then subsequent tensile tests were performed on these pre-fatigued specimens to obtain their stress-strain curves and associated mechanical properties (yield strength, ultimate strength, elastic modulus and ultimate elongation). Systematic comparative analyses for the evolution of residual mechanical properties of Q690 high-strength steel with different pre-fatigue damages were carried out. Significant differences are observed in the fracture position and the morphological features of fractures of Q690 high-strength steel with different pre-fatigue damages. Meanwhile, pre-fatigue damage also exerts distinct influences on yield strength, ultimate strength and ultimate elongation of Q690 high-strength steel. Specifically, the dramatic reduction is especially noted in ultimate elongation of Q690 high-strength steel due to pre-fatigue damage. In contrast, the influence of pre-fatigue damage on the elastic modulus of Q690 high-strength steel is negligible. When pre-fatigue damage is ranging from 0 to 0.6, the maximum decrease of ultimate elongation reaches up to 49.3% and the maximum reduction of yield strength is 11.1%, however the decline of elastic modulus is less than 4.0%. According to the experimental results, a new set of predictive equations were proposed to determine the mechanical properties of Q690 high-strength steel with pre-fatigue damage and to provide the fundamentals for appropriate pre-fatigue damage evaluation of Q690 high-strength steel structures.

Residual Mechanical Properties of High-Strength Steel Bolts after Exposure to Elevated Temperature

This paper presents results from experimental studies on residual mechanical properties of Grade 10.9 bolts exposed to elevated temperatures. The effects of various target temperatures on the residual mechanical properties, including ultimate and yield strengths, stress-strain response, and the failure modes of bolts, were investigated. Furthermore, the influence of temperature level, chemical composition of feedstock steels, and heat treatment parameters in the fabrication process of Grade 10.9 bolts on residual mechanical properties was studied. Data from the experiments indicate quick reduction in residual strength of the bolts when heated up to temperatures greater than 400°C, reaching to 50% of its ultimate strength when exposure temperature reaches 800°C. Tempering the temperature in the bolt manufacturing process and carbon content in steel are two other important factors besides exposure temperature that have a great influence on residual properties of Grade 10.9 bolts. Based on the experimental results, a set of predictive equations is also proposed for assessing the temperature-dependent residual mechanical properties in Grade 10.9 bolts.

Experiment of ductile fracture performances of HSSS Q690 after a fire

In this study, a total of 26 tests were conducted to investigate the post-fire properties of high strength structural steel (HSSS) Q690, including mechanical properties and ductile fracture properties. The purpose of this experimental study is to evaluate the residual properties of the HSSS Q690 after a fire. Tensile coupons obtained from the HSSS Q690 sheets were heated to various temperatures up to 900 °C, and then were cooled down in furnace to ambient temperature. Tensile coupon tests were carried out to obtain their post-fire nominal stress-nominal strain curves, post-fire true stress-true strain curves, corresponding mechanical properties (including yield stress, ultimate strength, Poisson's ratio, elastic modulus and elongation), and ductile fracture behaviors. Test results showed that the HSSS Q690 can keep the unchanged mechanical properties after it experiences temperatures up to 600 °C. And then two sets of prediction equations (one set of equations only based on test results in this study, and another set of equations based on test results of previous studies and this study) are obtained to evaluate the post-fire properties of HSSS. The results presented in this experimental study are expected to lead to accurate assessing the post-fire properties, including mechanical properties and ductile fracture properties, of the HSSS Q690.

Mechanical and ductile fracture performances of high strength structural steel Q690 after a fire: experimental investigation

Abstract In this study, a total of 26 tests were conducted to investigate the post-fire mechanical and ductile fracture performances of high strength structural steel (HSSS) Q690. The purpose of this experimental research is to evaluate the residual strength and residual ductility of the HSSS Q690 after a fire. Tensile coupons obtained from the HSSS Q690 sheets were heated to various temperatures up to 900℃, and then were cooled down in air to ambient temperature. Tensile coupon tests were carried out to obtain their post-fire nominal stress-nominal strain curves, post-fire true stress-true strain curves, corresponding mechanical properties (including yield stress, ultimate strength, Poisson’s ratio, elastic modulus and elongation), and ductile fracture behaviors. Test results showed that the HSSS Q690 can keep the unchanged mechanical performances after it experiences temperatures up to 600℃. And then a set of prediction equations are obtained to evaluate the post-fire mechanical performances of such high strength steels. The results presented in this experimental study are expected to lead to accurate assessing the post-fire performances, including mechanical performances and ductility performances, of the HSSS Q690.

A Practical Method for Assessing the Energy Consumption and CO2 Emissions of Mass Haulers

Mass hauling operations play central roles in construction projects. They typically use many haulers that consume large amounts of energy and emit significant quantities of CO2. However, practical methods for estimating the energy consumption and CO2 emissions of such operations during the project planning stage are scarce, while most of the previous methods focus on construction stage or after the construction stages which limited the practical adoption of reduction strategy in the early planning phase. This paper presents a detailed model for estimating the energy consumption and CO2 emissions of mass haulers that integrates the mass hauling plan with a set of predictive equations. The mass hauling plan is generated using a planning program such as DynaRoad in conjunction with data on the productivity of selected haulers and the amount of material to be hauled during cutting, filling, borrowing, and disposal operations. This plan is then used as input for estimating the energy consumption and CO2 emissions of the selected hauling fleet. The proposed model will help planners to assess the energy and environmental performance of mass hauling plans, and to select hauler and fleet configurations that will minimize these quantities. The model was applied in a case study, demonstrating that it can reliably predict energy consumption, CO2 emissions, and hauler productivity as functions of the hauling distance for individual haulers and entire hauling fleets.

A stochastic ground motion accelerogram model for Northwest Europe

This article presents a stochastic ground-motion accelerogram model for Northwest Europe which simulates accelerograms compatible with seismic scenarios defined by earthquake magnitudes 4<Mw<6.5, distance-to-site 10km<Repi<100km and different types of soil (rock, stiff and soft soil). This model is developed based on Rezaeian and Der Kiureghian (2008, 2010) [1,2] and is a set of predictive equations that define a time-modulated filtered white-noise process. Such predictive equations were calibrated by means of the random-effects regression technique using a subset of the European database of accelerograms. The model is validated in terms of PGA, PGV and spectral accelerations using GMPEs for the UK, Europe and Middle East, and other Stable Continental Regions. This model is the first of its kind for NW Europe.

Development of reference equations for spirometry in japanese children aged 6–18 years

Spirometry is the most widely used pulmonary function test and the measured values of spirometric parameters need to be evaluated using reference values predicted for the corresponding race, sex, age, and height. However, none of the existing reference equations for Japanese children covers the entire age range of 6-18 years. The Japanese Society of Pediatric Pulmonology had organized a working group in 2006, in order to develop a new set of national standard reference equations for commonly used spirometric parameters that are applicable through the age range of 6-18 years. Quality assured spirometric data were collected through 2006-2008, from 14 institutions in Japan. We applied multiple regression analysis, using age in years (A), square of age (A(2)), height in meters (H), square of height (H(2)), and the product of age and height (AH) as explanatory variables to predict forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV(1)), peak expiratory flow (PEF), forced expiratory flow between 25% and 75% of the FVC (FEF(25-75%)), instantaneous forced expiratory flow when 50% (FEF(50%)) or 75% (FEF(75%)) of the FVC have been expired. Finally, 1,296 tests (674 boys, 622 girls) formed the reference data set. Distributions of the percent predicted values did not differ by ages, confirming excellent fit of the prediction equations throughout the entire age range from 6 to 18 years. Cut-off values (around 5 percentile points) for the parameters were also determined. We recommend the use of this new set of prediction equations together with suggested cut-off values, for assessment of spirometry in Japanese children and adolescents.

Scaling property of regional floods in New South Wales Australia

Regional flood frequency analysis (RFFA) is often used in hydrology to estimate flood quantiles when there is a limitation of at-site recorded flood data. One of the commonly used RFFA methods is the index flood method, which is based on the assumptions that a region satisfies criterion of simple scaling and it can be treated homogeneous. Another RFFA method is quantile regression technique where prediction equations are developed for flood quantiles of interest as function of catchment characteristics. In this paper, the scaling property of regional floods in New South Wales (NSW) State in Australia is investigated. The results indicate that the annual maximum floods in NSW satisfy a simple scaling assumption. The application of a heterogeneity test, however, reveals that NSW flood data set does not satisfy the criteria for a homogeneous region. Finally, a set of prediction equations are developed for NSW using quantile regression technique; an independent test shows that these equations can provide reasonably accurate design flood estimates with a median relative error of about 27%.

Prediction of RBC aggregability and deformability by whole body bioimpedance measurements analyzed according to Hanai's mixture conductivity theory

Bioelectrical impedancemetry (BIA) has been used to evaluate hemorheological parameters in vitro, and whole body impedance measurements are also correlated to some hemorheologic factors, due to their close relationship with determinants of electric properties of blood. In previous studies, we have determined a set of predictive equations for hematocrit, whole blood viscosity and plasma viscosity in both sedentary and trained individuals. Recent developments of the interpretation of BIA analysis based on Hanai's mixture conductivity theory allows a more interpretative analysis of the relationships between these electric measurements and body composition. Impedance can be analyzed in terms of resistance and resistivity of the whole body and even more, assuming some simplifications, resistance R and resistivity ρ of total body water (TBW), extracellular water (ECW) and intracellular water (ICW). In this study we thus investigated relationships between blood rheology and these calculations of R and ρ in a sample of 83 subjects (age: 9-64 yr; BMI: 17-44 kg/m(2)). BIA was performed with a multifrequency bioelectrical impedancemeter using low intensity at the following frequencies: 1, 5, 10, 50 and 100 kHz. Viscometric measurements were done with a falling ball viscometer. Hematocrit was measured with microcentrifuge. We found a new prediction of Quemada's viscometric index of RBC rigidity "k" which was positively correlated to the resistance of ECW (R(e)) and even more if it was related to this volume: k = 0.005809 R(e)/ECW + 1.1784 (r = 0.487; Bland-Altman mean difference: 0.0124; range: -0.00481 to 0.00296). A new finding was that red blood cells (RBC) aggregability, that in the previous studies was not related to whole body impedance, despite its in vitro measurability with such measurements, was correlated to extracellular resistance and resistivity. The Myrenne index "M" was negatively correlated to the resistivity of the extracellular fluid ρe and is predicted by: M = -27.4755 ρ(e) + 1121.57029 (r = 0.463; Bland-Altman mean difference: 0.00194; range: -0.842 to 0.842). Furthermore, the SEFAM index "S(10)" is correlated to the ρe and is predicted by S(10) = -59.38579 (ρ(e)-40) + 63.083 (r = 0.761; Bland-Altman mean difference: 0.000722; range: -1.77 to 1.77). Therefore, a more in-depth analysis of electric properties of the body provides a closer approach of RBC rheology, although, of course, most remains to be understood in this intriguing domain.

Prediction of lean and fat composition in swine carcasses from ham area measurements with image analysis

Video images of ham cross-sections were recorded from 71 pork carcasses (ranging in weight from 72 to 119kg). Three sets of prediction equations were developed to estimate pork carcass lean and fat composition from video image analysis (VIA) of ham cross-sectional area measurements, 10th rib back fat depth (TENFAT) and hot carcass weight (HCKg). Carcass data of dissected lean and fat in the four primal cuts (ham, loin, Boston button and picnic shoulder) were used as dependent variables in establishing regression equations. The first set of equations combined VIA ham measurements and total ham weight (HTKg). Regression models containing the single variable HTKg times ham percentage lean area (Vol. 1) or HTKg times ham percentage fat area (Vol. 2) accounted for 88% and 68% of the variation in total carcass lean weight (CLKg) and total carcass fat weight (CFKg) from the right side of each carcass, respectively. The second set of equations combined VIA ham measurements and TENFAT (cm). Multiple regression models involving TENFAT, Vol. 1, and Vol. 2 accounted for 91% and 90% of the variation in CLKg and CFKg. The third set of equations used VIA ham measurements, TENFAT and HCKg. Carcass lean weight was best predicted by HCKg, TENFAT, and ham lean area (HLA) (R(2)=.92). Carcass fat weight was best predicted by HCKg, TENFAT, and Vol. 2 (R(2)=.91). Overall correlations showed a high association between Vol. 1 and CLKg (r=.94, P<.0001) and Vol. 2 and CFKg (r=.83, P<.0001). Ham lean area was related to CLKg (r=.74, P<.0001) and ham fat area to CFKg (r=.81, P<.0001). The results of this study indicated video image analysis of ham cross-section slices combined with backfat depth at the 10th rib can be used for accurate estimation of total carcass lean or fat composition.

Probabilistic seismic hazard assessment in Greece – Part 2: Acceleration response spectra and elastic input energy spectra

Abstract. This second part of the study, deals with the evaluation of the earthquake hazard in Greece in terms of the response spectral acceleration and the elastic input energy equivalent velocity. Four sets of predictive equations were selected, two for each type of spectra. Probabilistic hazard maps were created by determining the seismic hazard at grid points covering the region of interest. The maps are presented for the dominant periods of 0.2 s and 1.0 s for each spectrum. Uniform hazard response spectra (UHRS) for six cities located in the regions of highest estimated hazard are also presented. The comparison with elastic design spectra proposed by the latest national building code, has shown that the UHRS values exceed the design values at almost all periods.

Interaction of the properties of individual cotton fibres in a blend

Yarn engineering plays an important role in producing fabric for particular use. It is a common practice that yarn properties are predicted from constituent fibre properties. Cotton properties being highly variable in nature attracted various scientists from all over the world to derive prediction equations. More than 200 articles have been published in this area. Most of these predictions are based on single cotton, whereas in practice, more than one cotton is mixed together to optimise cost and quality. This study reports the accuracy of using weighted average method to determine the properties of blended cottons. Also, a set of prediction equations, derived for single cotton, tried to predict the properties of blended cotton yarns. To increase the accuracy of predictions, a new set of equations have been derived for binary cotton-blended yarns.

Clarification of vehicle cone index with reference to mean maximum pressure

The US Army developed Vehicle Cone Index (VCI) as a metric for directly quantifying the ability of vehicles to traverse soft-soil terrain. In order to ensure minimum soft-soil performance capabilities for their new military vehicles, the US Army has used VCI for many years as a performance specification. The United Kingdom’s Ministry of Defence (UK MOD) has used the Mean Maximum Pressure (MMP) parameter for many years as a performance specification. It has been demonstrated that the MMP parameter relates to soft-soil performance capabilities, and hence, the UK MOD has ensured minimum performance capabilities for their new military vehicles by using MMP specifications. Both the VCI and MMP specification approaches have served their users well, but fundamental differences in the two specification approaches have produced some misunderstandings concerning what VCI really is and how it relates to MMP. This article clarifies that VCI is a performance metric, not a set of predictive equations, explains how VCI is measured, and compares different methods of predicting VCI for one-pass performance (i.e., VCI 1) of wheeled vehicles in fat clay soils. It is further clarified that MMP should not be compared with VCI but instead with Mobility Index (MI), which is the principal parameter used by the US Army for predicting VCI. Relationships are presented for using MMP to predict VCI 1 for wheeled vehicles in clay, and the resulting relationships allow comparison between MMP and MI in terms of their ability to predict VCI. Seventy-nine VCI 1 performance measurements were used for the comparison, and they demonstrate that MI describes the historical performance data somewhat better than MMP.

Prediction of nutritive values in grass silages: II. Degradability of nitrogen and dry matter using digestibility, chemical composition, and fermentation data.

One hundred thirty-six perennial rye-grass silages with wide variations in quality were evaluated for N and DM degradability in three beef steers offered grass silage of medium quality ad libitum. The silages were incubated in the rumen of each animal in triplicate for 0, 6, 12, 24, 48, and 72 h, respectively. The disappearance rates of N or DM were used to calculate the readily soluble fraction ("a" value), potentially degradable fraction ("b" value), and the fractional degradation rate of"b" ("c" value). The effective degradability (P) of N or DM was then estimated assuming a ruminal outflow rate of 0.02, 0.05, or 0.08/h (P0.02, P0.05, or P0.08). The objective was to use these data to develop prediction equations for N and DM degradability in grass silages. There were considerable variations in "a," "b," and "c" values and the P0.02, P0.05, or P0.08 of N and DM (e.g., the P0.02 of N ranged from 75.0 to 93.4% and the P0.02 of DM from 51.5 to 82.5%). The P0.02, P0.05, or P0.08 of N and DM were negatively related (P < 0.001) to ADF, NDF, and lignin concentrations but positively related (P < 0.001) to protein fractions (CP, soluble CP, and true protein concentrations) and digestibility of DM, OM, GE, CP, and NDF and digestible OM in the total DM (measured with sheep). The N and DM degradability data were also positively related to silage lactic acid concentration, but the relationships between DM degradability data and pH, ammonia N/total N, and VFA concentration in silages were negative (P < 0.05). Several sets of prediction equations (linear and multiple) were thus developed for N and DM degradability using CP or NDF concentration, "a" value or digestibility data as primary predictors, together with or without other nutrient concentration and silage fermentation variables. All these relationships were highly significant (P < 0.001), and each predictor had a significant effect on the relationship (P < 0.05). The R2 values in multiple regression for N and DM degradability were generally over 0.70 and higher than in linear regression equations. Four equations were also developed to convert N and DM degradability at a given ruminal outflow rate, predicted using the above-mentioned equations, to their counterparts at any ruminal outflow rate (0.02 to 0.10/h), respectively.

References values for forced spirometry. Group of the European Community Respiratory Health Survey.

The European Coal and Steel Community (ECSC) prediction equations exemplify a significant effort carried out approximately 15 yrs ago to provide uniform standards for lung function testing, but this set of equations has not been properly validated as yet. The present study evaluates the ECSC reference values and four other sets of prediction equations, using spirometric data collected in 12,900 nonasthmatic subjects (43% lifetime nonsmokers and 36% active smokers) aged 20-44 yrs from the European Community Respiratory Health Survey (ECRHS). Standardized spirometric measurements were obtained using a common protocol in 34 centres in 14 countries. For each prediction equation, the prediction deviations (i.e. observed minus predicted value) for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were examined for the whole study population and for each centre. For the age range included, the errors about the ECSC equations showed the most prominent underestimation of both predicted FVC (+355 and +360 mL on average in males and females, respectively) and predicted FEV1 (+211 and +200 mL, respectively) among the five studies examined. As expected, FVC and FEV1 in active smokers from the ECRHS were significantly lower than in lifetime nonsmokers (each p<0.01). We conclude that the present European recommendations on lung function reference values should be reconsidered, but further data for nonsymptomatic subjects above the age of 44 yrs are needed.

Improved equations for JPEG's blocking artifacts reduction approach

In this paper, we derive a new set of prediction equations for the block smoothing method of JPEG for reduction of blocking artifacts. We also devise some simple metrics to measure the effects of edging and ringing artifacts. Experiments show that at the bit rate of 0.3 b/p or less, images reconstructed using the proposed equations have significantly fewer number of artifacts compared to the images reproduced using the original set of equations.

Improved image reproduction from dc components

The Joint Photographic Expert Group standard provides a block smoothing method, that can be used to improve the visual quality of images reproduced from the dc coefficients alone. The method predicts ac coefficients of a block in terms of the dc values of the surrounding blocks. This note presents a new set of prediction equations. Experiments show that the proposed equations produce noticeable improvements in the visual quality of the reconstructed images.