A new three PARAMETER Equation Of STATE (EOS) is developed based on well documented data, at three thermodynamic STATEs of the critical point, the normal bubble point and standard condition. Besides these STATEs, the EOS is designed to satisfy the condition of nearly zero Joule-Thomson (JT) coefficients at the normal boiling point. Critical properties and densities at the normal boiling point and a standard condition of more than 100 pure fluids were used. The new EOS is validated using experimental data and eight (8) of the popular EOSs, namely, SRK, PR, LLS, HK, MNM, SW, PT and ALS. The experimental data for pure fluids include 331 data points of vapor pressure covering 12 fluids and compressibility at the critical condition of 23 fluids. For mixtures, the data includes 129 PVT data points of 12 reservoir fluids [seven (7) of them are Sudanese crude oil considered for publication for the first time and five (5) from literature]. The new EOS is found to be superior to the existing EOSs in the prediction of PVT properties of mixtures with a grand average percent absolute deviation (AAPD) of 3.18%. It is also comparable to the existing EOSs in the prediction of vapor pressure despite the fact that existing EOSs are developed based on vapor pressure data; the grand average AAPD is 2.0. In terms of compressibility at the critical point with the exception of LLS, the new EOS yields better results than all other EOSs considered in this work.

Ionic polymer metal composite (IPMC) actuator is a group of electro-active polymers (EAPs) which bend in response to a relatively low electrical voltage because of the motion of cations in the polymer network. IPMC has a wide range of applications in robotics, biomedical devices and artificial muscles. The modeling of the IPMC actuator is a multi-physics task as it involves the electricity, chemistry, dynamics and control fields. Due to its complexity and nonlinearity, IPMC modeling is difficult in terms of mathematics and its behavior is still not fully agreed upon by researchers. This paper presents a novel discrete-time model with STATE-dependent PARAMETERs (SDP) for identification of the nonlinear response of an IPMC actuator. A single-input single-output nonlinear identification algorithm is formulated and demonstrated for an IPMC actuator that exhibits both soft and hard nonlinearities. The nonlinear characteristics of the identified system are represented with coefficients which are a function of the input and output STATEs. Following the SDP algorithm, the model is identified from input–output data to represent the model PARAMETERs as functions of past inputs and outputs. The proposed modeling approach is validated using an existing model and shows exact representation of the non-linear behavior of the IPMC actuator.

The capability of sand constitutive models is remarkably improved by taking into account the effect of soil STATE in their formulations. In this study, it has been shown that considering the effect of soil STATE leads to better simulation of soil instability of shear banding type. To this aim, constitutive equations of a STATE dependent sand model are explained first. Consequently, the general conditions of instability and then, the special condition of instability with respect to the model formulation has been obtained. Using the result of a number of plane strain tests, the STATE dependent model predictions for shear band have been compared with experiment results. It has been shown that, predictions obtained from a similar model which neglect the effect of soil STATE are less favorable.

In this paper, the robust gain-scheduled STATE-feedback controller problem is studied for uncertain linear PARAMETER-varying systems whose STATE-space representations are the linear combination of the uncertain time-varying PARAMETERs including time-invariant parametric uncertainties (TIPU). It is supposed that these uncertainties are bounded by the given intervals and cannot be pulled out as an uncertain block. It is considered a serious challenge because the exact information about the plant dynamics cannot be extracted from the uncertain time-varying PARAMETERs. This is while; the gain-scheduled controllers need to have the exact information about the plant dynamics to satisfy the desired control purposes. To handle this challenge, we introduce a STATE-feedback gain, which is formed by a set of the new scheduling PARAMETERs and a secondary time-varying term. The stabilization conditions are obtained in terms of the linear matrix inequalities (LMIs). The effectiveness of the proposed method is shown using an example.

Purpose: To determine refractive STATE and corneal PARAMETER changes after cycloplegia with cyclopentolate 1% using dual scheimpfluge imaging system.Methods: Healthy volunteers between the ages of 10 and 40 years who were referred for ophthalmic evaluation in a 3-month period were included. Complete ophthalmic examination, auto-refraction and corneal imaging with the Gallilei dual scheimpfluge system was performed before and after 30 minutes of applying 1% cyclopentolate. Changes in refractive and corneal PARAMETERs were evaluated.Results: One hundred and six patients with mean age of 28±5 years or 212 eyes (201 myopic and 11 hyperopic) were evaluated. The mean spherical equivalent before cycloplegia was -3.4 ± 2.6 D (diopter), after cycloplegia the mean hyperopic shift was 0.4±0.5 D (P<0.001). The astigmatism power change was not significant (P=0.8), but in 26.6% of 127 eyes, with more than 0.5D astigmatism, the axis changed more than 5 degrees after cycloplegia. Anterior corneal curvature change was not statistically significant (p=0.5) but posterior corneal curvature change was statistically significant (P=0.001) and in the direction of hyperopic shift (diff=-0.02).Corneal thickness increased statistically and significantly in the central and para-central areas, respectively {(diff=3.2 micron (P<0.001) and 3.9 micron (P<0.001)}.Conclusion: The refractive STATE, posterior corneal curvature and corneal thickness changed statistically and significantly after cycloplegia, so it is recommended not to measure these PARAMETERs in cycloplegic STATE for clinical judgment, in IOL power calculation and refractive surgery.

In this study, the effect of STATE PARAMETER in elasto-plastic constitutive models on improvement of predicting sand behavior was studied, using DIANA-SWANDYNE II program. The centrifuge test results, which were obtained in VELACS workshop, were used in this study. The mechanical behaviors of centrifuge models under earthquake loading was predicted by using Pastor & Zienkiewicz Mark III constitutive model and the modified model and were compared with experimental results. The results show that the use of current STATE PARAMETER can have a significant effect on improvement of predicting deformation, water pore pressure and acceleration caused by earthquake loading in soil structures.