Straight-line Extrapolation Research Articles

Decision support system (DSS) for facilities rehabilitation and management (part 2): development of optimized intervention strategy

PurposeThis paper (Part 2 of 2) aims to expand the previously developed performance assessment model (PAM) into a decision support system (DSS) to produce optimized decisions on rehabilitation of facilities.Design/methodology/approachThe research includes a comprehensive PAM that integrates analytical hierarchy process-multi attribute utility theory methods for the physical, operational, and environmental aspects of the mosque, as described in Part 1 of the study. An optimized intervention tool is added to the PAM to complete the DSS development. The tool determines the optimum maintenance decisions that are in line with the budget and condition criticality. The deterioration measures are created using a deterministic straight-line extrapolation technique, and the intervention actions used in the optimization are specified through literature review and in-depth interviews with 11 experts. The optimization model was simplified into a user-friendly visual basic application and applied to an existing facility case study depicting its useful functionality.FindingsThe optimization model recommendation of interventions recovered the overall condition rating index (CRI) of the facility while maintaining budget constraints. The CRI in the first approach (minimum budget to achieve acceptable overall performance) was improved from 6.5 to 7.76, costing 275,850 SAR. While the second approach (Maximum recovery with a selected budget constraint, 300,000 SAR in this case) CRI was improved from 6.5 to 8.3, costing 299,850 SAR.Originality/valueThe presented DSS in this paper offers a tool that enables the rehabilitation and overall management of any facility by its managers. The DSS can also be further customized to fit the facility manager’s specific strategies and achieve desired objectives.

John - Sivanandan Achari Isotherm Method for the Determination of Surface Area of Porous Materials: Analysis of Granular Activated Carbons

John –Sivanandan Achari isotherm equationlog log Ce= C+n log qe,has many advantages for the structural characterization of porous materials. Linear plot of log logCe versus log qe conform to a straight line and subsequent extrapolation of amount adsorbed (qe), to the xaxis. This way one can directly determine the monolayerqm(J-SA) and hence the specific surface area (SA m2 /g) of the material.This can be analytically proved by applying the method in any type of solid-liquid equilibrium adsorption data. In this study, adsorption of methylene blue (MB) dye molecules on modified granular activated carbon (GAC) has been attempted to determine the porosity, and surface area by the new method. The solids are GAC 383 (native carbon- coconut shell based), GACO383 (native carbon oxidized) and a new carbon (GACOLaO1273). This carbon is prepared in the laboratory by steam activation after incorporating GAC383with Lanthanum(La 3+) ions. Carbons are tested in batch reactors with fixed MB concentrations by adsorptive techniques. The isotherm model behavior of the carbons are hereby reported using John - Sivanandan Achari isotherm (J-SA) equation using specific adsorption data. Porous material category as IUPAC type, constants and parameters are further evaluated with Langmuir, Freundlich, Dubinin - Radushkevich isotherms. It is seen that the isotherm followed the features of micro porous materials on using John – Sivanandan Achari (J-SA) isotherm. Porosity and surface area determined are found to give agreeing results on comparing with other isotherm models. This research is intended to highlight the significance of John and John-Sivanandan Achari (J-SA) isotherms as a tool for material characterization studies- a model originated as Indian analytical scientific skill.

Production Data Analysis Techniques for the Evaluation of the Estimated Ultimate Recovery (EUR) in Oil and Gas Reservoirs

The calculation of oil reserves (estimate ultimate recovery, EUR) is required for reservoir management. It is important to differentiate between oil reserves and oil resources. The latter is roughly defined as the sum of recoverable and unrecoverable volumes of oil in place; whereas, the oil reserves can be defined as those amounts of oil anticipated to be commercially recoverable from a given date under defined conditions. However, there is always uncertainty when making reserve estimates, and the main source of uncertainty is the lack of available geological data. Depending on the quantity and quality of the available data, different methods are used for the evaluation of the EUR. A number of essentially straight-line extrapolation techniques (production data analysis) have been proposed to estimate the EUR for oil and gas wells. Thus, a detailed analysis of past performance of oil and water production data is required in order to predict the future performance of the oil and gas wells. This work utilized seven straight-line extrapolation techniques to estimate and compare the values of EUR of three oil wells from the same reservoir. The comparison shows very similar estimated EUR. Doi: 10.28991/HIJ-2022-03-01-09 Full Text: PDF

Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing.

To improve the predictive capability of long-term stress relaxation of elastomers during thermo-oxidative ageing, a method to separate reversible and irreversible processes was adopted. The separation is performed through the analysis of compression set after tempering. On the basis of this separation, a numerical model for long-term stress relaxation during homogeneous ageing is proposed. The model consists of an additive contribution of physical and chemical relaxation. Computer simulations of compression stress relaxation were performed for long ageing times and the results were validated with the Arrhenius treatment, the kinetic study and the time-temperature superposition technique based on experimental data. For chemical relaxation, two decay functions are introduced each with an activation energy and a degradative process. The first process with the lower activation energy dominates at lower ageing times, while the second one with the higher activation energy at longer ageing times. A degradation-rate based model for the evolution of each process and its contribution to the total system during homogeneous ageing is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing a straight-line extrapolation.

The Evolution of Interfacial Strength as a Way to Characterize a Low-Temperature Limit of the Surface Glass Transition of an Amorphous Polymer

The evolution of autoadhesive strength, σ, with healing temperature, T h, at the symmetric amorphous polystyrene (PS)−PS interfaces of the samples with vitrified bulk has been used to characterize a low-temperature limit of the surface glass transition temperature T g surface(low). The existence of a linear relationship between the square root of σ and T h has been found for both polydisperse and monodisperse polymers. By the extrapolation of straight lines σ 1/2 − T h to σ 1/2 = 0, the values of T g surface(low) have been determined and compared with those of a high-temperature limit of T g surface, T g surface(high), measured earlier. The differences between T g surface(low) and T g surface(high) have been found to be insignificant, 10–20°C. Using an average value of the shift of T g surface(low) with healing time, t h, the quasi-equilibrium value of the surface glass transition temperature of amorphous PS T ∞ surface has been estimated to be 10–15°C.

A new technique for extracting the red edge position from hyperspectral data: The linear extrapolation method

The position of the inflexion point in the red edge region (680 to 780 nm) of the spectral reflectance signature, termed the red edge position (REP), is affected by biochemical and biophysical parameters and has been used as a means to estimate foliar chlorophyll or nitrogen content. In this paper, we report on a new technique for extracting the REP from hyperspectral data that aims to mitigate the discontinuity in the relationship between the REP and the nitrogen content caused by the existence of a double-peak feature on the derivative spectrum. It is based on a linear extrapolation of straight lines on the far-red (680 to 700 nm) and NIR (725 to 760 nm) flanks of the first derivative reflectance spectrum. The REP is then defined by the wavelength value at the intersection of the two lines. The output is a REP equation, REP = − ( c 1 − c 2) / ( m 1 − m 2), where c 1 and c 2, and m 1 and m 2 represent the intercepts and slopes of the far-red and NIR lines, respectively. Far-red wavebands at 679.65 and 694.30 nm in combination with NIR wavebands at 732.46 and 760.41 nm or at 723.64 and 760.41 nm were identified as the optimal combinations for calculating nitrogen-sensitive REPs for three spectral data sets (rye canopy, and maize leaf and mixed grass/herb leaf stack spectra). REPs extracted using this new technique (linear extrapolation method) showed high correlations with a wide range of foliar nitrogen concentrations for both narrow and wider bandwidth spectra, being comparable with results obtained using the traditional linear interpolation, polynomial and inverted Gaussian fitting techniques. In addition, the new technique is simple as is the case with the linear interpolation method, but performed better than the latter method in the case of maize leaves at different developmental stages and mixed grass/herb leaves with a low nitrogen concentration.

Oxidation induction time studies on the thermal degradation behaviour of polyoxymethylene

The thermo-oxidative stability of two types of commercially available polyoxymethylene (POM) in various ageing conditions has been studied by applying the Oxidation Induction time (OIt) method, which is a special technique of conventional differential scanning calorimetry (DSC). The results reveal that the proposed method is appropriate to characterise the stabiliser consumption in POM during thermal ageing. It is found that the OIt event is predominately based on endothermic processes under the applied experimental conditions, which is in clear contrast to polyolefins. However, the ability to differentiate different processed and aged POM samples decreases significantly with increasing OIt test temperature. Corresponding Arrhenius plots of the OIt results for POM reveal that straight line extrapolation from high to low temperatures is not feasible due to the two segment nature of the OIt.

The ab-plane optical conductivity of overdoped La 2− xSr xCuO 4 for x=0.184 and 0.22: evidence of a pseudogap

The reflectance of high-quality single crystals of La 2− x Sr x CuO 4, with x=0.184 and 0.22, has been measured with the electromagnetic radiation polarized along the ab-plane for frequencies between 30 cm −1 and 9000 cm −1 (0.004–1.1 eV) and for temperatures varying from 10 K to 300 K. In the normal state, the overdoped samples develop a gap-like depression below T* in both the conductivity and the scattering rate. A signature of the pseudogap state is a depression of 1/ τ( ω, T) below the high-frequency straight-line extrapolation. This feature can be seen for temperatures below the superconducting transition all the way up to room temperature for the material with the nominal Sr concentration of 0.184. In the case of La x Sr 2− x CuO 4+ δ with x=0.22 the pseudogap state exists below 200 K.

Temperature evolution of the pseudogap state in the infrared response of underdopedLa2−xSrxCuO4

The ab-plane optical spectra of two single crystals of underdoped La_(2-x)Sr_xCuO_4 were investigated. The reflectivity of La_(1.87)Sr_(0.13)CuO_4 has been measured in the frequency range 30- 9,000 cm-1 (0.004 -- 1 eV) both parallel and perpendicular to the CuO_2 planes, whereas La_(1.86)Sr_(0.14)CuO_4 was studied only in the ab-plane. The extended Drude model shows that the frequency-dependent effective scattering rate 1/tau(omega)is strongly suppressed below the high-frequency straight-line extrapolation, a signature of the pseudogap state. This suppression can be seen from temperatures below the superconducting transition up to 400 K. In the case of underdoped LSCO the straight-line extrapolation is temperature independent below 200 K, whereas above 200 K there is a strong temperature dependence of the high-frequency 1/tau(omega,T). The out-of-plane direction is also examined for evidence of the pseudogap state.

Three scenarios for the future of China

As we begin to think about the twenty-first century, we are entering a time of fundamental global change. the most dramatic shift will be the movement of China to the status of great power. Yet, the only specific forecast for the future of China that we can make with confidence is that a straight-line extrapolation is most unlikely to occur. China will not continue to grow at double digit rates for the coming decade. Nor is the rest of Southeast Asia going to grow at the 8 percent that has been registered for the past decade and more. Nor is everything going to go smoothly.

Response of random dielectric composites and earthquake models to pulses: prediction possibilities

Following the success of the study of response to local short-duration pulses (of magnetic field, additional ‘sands’, etc.) on magnetic systems and the BTW (sand-pile) model, to locate accurately the respective critical points, the responses to similar short duration pulses (of electric field, of ‘mechanical pushes’ on tectonic plates, etc.) have been studied here numerically for metal-insulator composites before dielectric breakdown and the Burridge-Knopoff (earthquake) model before the critical avalanches. The breakdown susceptibility (defined in the text), obtained from such response behaviour, indicates universal behavior near the catastrophic breakdown or the self-organised critical points. We show that the breakdown (electric) feld for random metal-dielectric composites can be located accurately much before the breakdown, by extrapolating the inverse breakdown susceptibility to its vanishing point. Similarly, the growth of the susceptibility, coming from the stress correlations, in the Burridge-Knopoff model of earthquakes is shown to be exponential in time. Prediction of the earthquake point (in time) is also possible in the model from the study of its inverse logarithm with straight-line extrapolation to its vanishing point.

Have Animal Data Been Used Inappropriately to Estimate Risks to Humans from Environmental Trichloroethylene?

Trichloroethylene (TCE) is widely viewed as an environmental hazard. Its major metabolite, chloral hydrate, is a currently used medicine. Regulation of TCE is based on a linear extrapolation from effects of high doses in rodents to risks for humans at low doses. However, metabolic, toxicologic, and epidemiologic data on trichloroethylene and chloral hydrate as well as water chlorination studies call this approach into question. The mechanism of carcinogenesis of TCE and chloral hydrate in rodents is nonlinear: very high doses, sufficient to cause cellular necrosis, are necessary. Malignancy arises from repeated cycles of necrosis and regeneration with the ultimate emergence of hyperplasia and then neoplasia. Metabolites of TCE, trichloroacetic acid and dichloroacetic acid, mediate this toxic effect of TCE. These chloroacetic acids also induce similar lesions in rodents given high doses of the medicine, chloral hydrate. Human epidemiologic data show no increase in mortality or malignancy from substantial chronic exposure to trichloroethylene. Chlorination of drinking water produces much higher levels of chloroacetic acids than could be obtained from metabolizing TCE under current regulations. We conclude that the assumptions underlying current regulations are not applicable to TCE. Instead of a straight-line extrapolation model, a threshold model may be more appropriate. The data suggest that it is possible to increase substantially the allowable trichloroethylene in drinking water without increasing health hazards.

A Simplistic Evaluation of Over 30 Years' Horizontal Hydrocarbon Solvent Flood Performance In Alberta

Abstract The following discussion will examine the trends in performance shown by mature projects in an attempt to expose reasons for encouraging/discouraging results. Inferences drawn from the information presented are those of the author. The reader is left with the responsibility of building them into useful conclusions. Data Resources Bias in the interpretation of the performance of the 10 project areas studied was avoided by limiting the data used to Alberta Energy Resources Conservation Board (AERCB) records:Defined project areas and the wells within themAverage reservoir factors and discovery datesInitial oil in placeProduction and injection history filesExecutive summaries and maps in operations reports The parameters used in relation to the performance analysis are presented in Table I. Analysis Concepts As a start, a small set of key performance measuring parameters was sought. After examining alternatives oil rate performance was perceived to be the most useful parameter, particularly with regard to establishment of stable decline to ultimate recovery and reaction to changes in reservoir depletion process. Producing water-oil and gas-oil ratios were included, indicating ability to keep injected fluid in the reservoir and success of management strategies. Total liquid production completes the set used giving information about reflection of wells to changes in reservoir depletion process and operations aimed at reducing production of injected fluids. The selection of study variables immediately led into a "decline curve" approach, so that plots against a reservoir dependent parameter could be extrapolated to yield inferences about future performance and ultimate expectations. Cumulative oil production since discovery was selected as a common yardstick, to avoid the impact of difference in reservoir quality and depletion rate strategies. Cumulative oil production was divided by rated initial oil in place, and became "depletion", plotting between 0.0 and 1.0. Oil and total liquid production rates were divided by the peak value attained, plotting between 0.0 and 1.0. Producing gas-oil ratio was divided by initial solution gas-oil ratio, plotting between 1 and the chosen practical or "economic" limit of 15. Water-oil ratio is already normalized, plotting between 0.0 and the chosen practical or "'economic" limit of 20. Space does not permit printing the entire set of performance plots developed. Their salient features are discussed below, and the slopes for the straight line extrapolations are presented in Table 2. Capability to re-create the plots from the public data is within reach of anyone desiring to do so. The plots for Fenn-Big Valley South Lobe Project 338 and Kaybob South Triassic "A" Project 165 are presented as Figures 1–4 to show favorable and unfavorable changes in reservoir behavior resulting from horizontal solvent flood. Project Performance Reviews The projects are presented in alphabetical order by pool name to avoid ordering bias. Wherever practical, more than one parameter is extrapolated to show the range of possible outcomes for a project. Ante Creek Project 2 The Ante Creek Beaverhill Lake "A" Pool carbonate reef was discovered in 1962. The location was remote from gas processing and transportation facilities.

A study of the mechanics of microindentation using finite elements

In this paper the finite element method is used to explore the mechanics of the microindentation process. In the simulations discussed, aluminum and silicon are investigated both in their bulk forms and in thin film-substrate combinations. Among the quantities readily computed using this approach and given in this paper are hardness (computed using actual contact area), contact stiffness, effective composite modulus, and surface profile under load. Importantly, this investigation builds on previous work by providing a more critical examination of the amount of pileup (or sink-in) around the indenter in the fully loaded configuration, as well as the variation of the actual contact area during indenter withdrawal. A key conclusion of this study is that finite element simulations do not support the widely used assumption of constancy of area during unloading (for either bulk materials or thin film systems). Furthermore, the amount of pileup or sink-in can be appreciable. The implication of these findings is that for many situations the commonly used straight-line extrapolation of a plastic depth may render an estimate for the contact area that is quite distinct from the actual area. This assertion is demonstrated herein through comparison of hardnesses calculated using actual contact area with values calculated using the straight-line extrapolation of plastic depth.

Parameter Estimation for Hyperbolic Decline Curve

The problem of estimating the nonlinear parameters associated with the hyperbolic decline curve equation is considered in this paper. Estimation equations are developed to estimate these nonlinear parameters. The condition under which the results can be used to predict future oil productions is examined using actual field data. An approximate linear term is obtained from the nonlinear hyperbolic equation through Taylor’s series expansion, and the optimum parameter values are determined by employing the method of least squares through an iterative process. The estimated parameters are incorporated into the original hyperbolic decline equation to provide realistic forecast function. This method does not require any straight line extrapolation, shifting, correcting and/or adjusting scales in order to estimate future oil and gas predictions. The method has been successfully applied to actual oil production data from a West Cameron Block 33 Field in South Louisiana. The results obtained are provided in Fig. 1.

Oxidation stability of crosslinked polyethylene. Isothermal DTA method

Isothermal differential thermal analysis has been used to study the thermooxidative stability of two grades of crosslinked polyethylene in the temperature range from 120°C to 230°C. Induction times of thermooxidative degradation were measured from 2 minutes up to 3590 hours. Oxidation Induction time and mechanical failure in oven ageing experiments coincided over the measured temperature range. The degree of crosslinking was not strongly affected by the oxidative reaction. The Arrhenius-plots of DTA results showed curvature at 150°C, so straight line extrapolations from short-term experiments at elevated temperatures to low temperatures and long times are not possible. Thermoanalytically measured residual thermooxidative stability decreased linearly with ageing time and showed great scattering of the results.

Measurement of thermooxidative stability of polyolefins by isothermal differential thermal analysis

AbstractIsothermal differential thermal analysis (DTA) is a well known method of testing thermooxidative stabilities of polyolefins. Oxidation induction times, measured up to 7000 hours and over a temperature range from 260°C to 130°C has been used to study the stability of polybutene‐1 in the melt state.The Arrhenius plots of DTA results show that straight line extrapolation from high to low temperatures is not possible. Thermoanalytically measured oxidation induction times and mechanical failure in oven ageing experiments agree well for polybutene‐1. Measurements of molecular weight and of mechanical properties of polybutene‐1 during the induction period of oven ageing experiments revealed that molecular weight and tensile properties are not sensitive indicators for the beginning of ageing. The state of deterioration can be estimated easier by measurement of residual lifetime in the isothermal DTA experiment. At high ageing temperatures the residual lifetime decreased linearly during the induction period, at ageing temperatures below 160°C the decrease of residual lifetime was found degressive.Finally the extraction of stabilizer by not water could be measured by isothermal DTA.

Thermo‐oxidative degradation of polyolefins observed by isothermal long‐term DTA

AbstractIsothermal differential thermal analysis (DTA) is well known for measuring thermal stability of polyolefins by determining the oxidative induction time at elevated temperatures. Oxidative induction time, measured up to 7,000 hours and over a temperature range from 240°C to 120°C, has been used to study the stability of polybutene‐1 and crosslinked polyethylene in the melt state. The Arrhenius plots of DTA results show that straight line extrapolation from high to low temperatures is not possible. Thermoanalytically measured oxidation induction times and mechanical failure in oven aging experiments agree for polybutene and crosslinked polyethylene, Measurements of molecular weight and of mechanical properties of polybutene‐1 during the induction period of oven aging experiments at low temperatures revealed that molecular weight and tensile properties are not sensitive indicators for the beginning of aging. The state of deterioration can be estimated easier by measurement of residual lifetime in the isothermal DTA experiment. Diffusion processes of stabilizers in polyolefins, as well as the consumption of stabilizer at elevated temperatures, especially during the induction period also was observed by DTA. Finally the extraction of stabilizer by hot water was measured by isothermal DTA.

An extrapolation method for the determination of Cliff‐Lorimer kAB factors at zero foil thickness

SUMMARYAn extrapolation method is proposed to be useful for the determination of the Cliff‐Lorimer kAB factor at zero foil thickness. The method consists of measuring kAB factors as a function of the measured foil thickness, tM, and extrapolating the relationship toward tM=0. The intersection between the extrapolated line and the ordinate of tM=0 gives (kAB)0 which is free from the effect of absorption. The straight line extrapolation that can be achieved by a linear‐least squares method is particularly developed to eliminate arbitrariness introduced in the extrapolation process.The extrapolation method is applied to data available in the literature. It is shown that the method yields the (kAB)0 factors compatible with those predicted from the theoretical calculation. It is also shown that this method can circumvent several problems which make it complex and difficult to determine accurate values of the absorption‐free kAB factors.Using the straight line extrapolatioin, it is possible to estimate the degree of the thickness overestimation which arises when the foil thickness is measured by the contamination spot separation (CSS) method. Validity of the straight line extrapolation is further discussed.

Measurement of oxidation stability of polyolefins by thermal analysis

Isothermal differential thermal analysis has been used to study the thermal stability of polybutene and crosslinked polyethylene in the temperature range from 120°C to 240°C. Oxidation induction times were measured from 2 min up to 7250 h. The Arrhenius-plots of DTA results showed curvature at 150°C, so straight line extrapolations from short-term experiments at elevated temperatures to low temperatures and long times are not possible. Oxidation induction time and mechanical failure in oven ageing experiments coincided over the measured temperature range. Decrease in the molecular weight of polybutene accelerated after the end of the induction period. Thermoanalytically measurable residual thermal stability decreased linearly with ageing time and is a more sensitive indicator of the beginning of thermal degradation than measurement of tensile properties. Finally, the extraction of stabilizer by hot water was measured by isothermal DTA.