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The paper explored the benefits as well as the concerns of vocabulary learning with clay modeling in terms of practical and pedagogical implications for creating positive learning experiences.

A mixed-methods design was conducted to examine the effectiveness of vocabulary learning with clay modeling practices in lower socioeconomic status schools.

Although test results showed no statistically significant differences between the groups, the clay modeling group did improve vocabulary acquisition similar to the sentence writing group. The students were actively engaged with hands-on activities using the clay and also demonstrated positive emotional, behavioral and physical experiences.

The addition of the clay modeling provided an opportunity for kinesthetic learning but created a high extraneous cognitive load with the challenges incurred through the use of clay.

The challenges can be reduced by 1) adopting appropriate instructional strategies to design and implement effective clay modeling activities for students and teachers, 2) providing training or professional workshop development for teachers and 3) ongoing practical support and assistance for students.

Exploring the use of kinesthetic instructional practice at the high school level may prove beneficial since clay modeling is frequently used effectively at lower grade levels.

The current study explores the added value of clay modeling for high school students’ biology vocabulary learning in a lower socioeconomic status school from practical and pedagogical perspectives.

A large‐strain/high‐deformation rate model for clay‐free sand recently proposed and validated in our work [1,2], has been extended to sand containing relatively small (< 15vol.%) of clay and having various levels of saturation with water. The model includes an equation of state which represents the material response under hydrostatic pressure, a strength model which captures material behavior under elastic‐plastic conditions and a failure model which defines conditions and laws for the initiation and evolution of damage/failure in the material. The model was validated by comparing the computational results associated with detonation of a landmine in clayey sand (at different levels of saturation with water) with their computational counterparts.

The purpose of this paper is to analyze, computationally, the kinematic response (including large‐scale rotation and deformation, buckling, plastic yielding, failure initiation, fracture and fragmentation) of a pick‐up truck to the detonation of a landmine (shallow‐buried in one of six different soils, i.e. either sand, clay‐laden sand or sandy gravel, each in either dry or water‐saturated conditions, and detonated underneath the vehicle) using ANSYS/Autodyn, a general‐purpose transient non‐linear dynamics analysis software.

The computational analysis, using ANSYS/Autodyn, a general‐purpose transient non‐linear dynamics analysis software, included the interactions of the gaseous detonation products and the sand ejecta with the vehicle and the transient non‐linear dynamics response of the vehicle.

The results obtained clearly show the differences in the blast loads resulting from the landmine detonation in dry and saturated sand, as well as the associated kinematic response of the vehicle. It was also found that the low frequency content of the blast loads which can match the whole‐vehicle eigen modes is quite small so that resonance plays a minor role in the kinematic/ballistic response of the vehicle. Furthermore, it was demonstrated that mine blast analytical loading functions which are often used in transient non‐linear dynamic analyses have limited value when used in the analyses of a complete vehicle.

This is the first time that the kinematic response of a pick‐up truck to the detonation of a shallow‐buried landmine (using a full‐scale/complete model) has been analyzed computationally.

The purpose of this paper is to suggest an implicit integration method for updating the constitutive relationships in the newly proposed anisotropic egg-shaped elastoplastic (AESE) model and to apply it in ABAQUS.

The implicit integration algorithm based on the Newton–Raphson method and the closest point projection scheme containing an elastic predictor and plastic corrector are implemented in the AESE model. Then, the integration code for this model is incorporated into the commercial finite element software ABAQUS through the user material subroutine (UMAT) interface to simulate undrained monotonic triaxial tests for various saturated soft clays under different consolidation conditions.

The comparison between the simulated results from ABAQUS and the experimental results demonstrates the satisfactory performance of this implicit integration algorithm in terms of effectiveness and robustness and the ability of the proposed model to predict the characteristics of soft clay.

The rotational hardening rule in the AESE model together with the implicit integration algorithm cannot be considered.

The singularity problem existing in most elastoplastic models is eliminated by the closed, smooth and flexible anisotropic egg-shaped yield surface form in the AESE model. In addition, this notion leads to an efficient implicit integration algorithm for updating the highly nonlinear constitutive equations for unsaturated soft clay.

Elasto‐plastic models based on critical state formulations have been successful in describing many of the most important features of the mechanical behaviour of soils. This review paper deals with the applications of this class of models to the numerical analysis of geotechnical problems. After a brief overview of the development of the models, the basic critical state formulation is presented together with the main modifications which have actually been used in computational applications. The problems associated with the numerical implementation of this type of models are then discussed. Finally, a summary of reported computational applications and some specific examples of analyses of geotechnical problems using critical state models are presented.

Several constitutive models are available in the literature to describe the mechanical behaviour of cement stabilized soils. However, difficulties in implementing such models within commercial finite element programs have hindered their application to solve related boundary value problems. Therefore, the aim of this study is to implement a constitutive model, which has the capability to simulate cement stabilized soil behaviour, into the finite element program ABAQUS through the user material subroutine UMAT.

After a detailed review of existing constitutive models for cement stabilized soils, a model based on the elasto‐plastic theory and the extended critical state concept with an associated flow rule is selected for the finite element implementation. A semi‐implicit integration method (cutting plane algorithm) with a continuum elasto‐plastic modulus and path dependent stress prediction strategy has been used in the implementation. The performance of the new finite element formulation of the constitutive model is verified by simulating triaxial test data using the finite element program with the new implementation and predictions from constitutive equations as well as experimental data.

The paper provides the implementation procedure of the constitutive model into ABAQUS but this method is useful for the implementation of any other constitutive model into ABAQUS or any other finite element program. Simulated results for the volumetric deformation of cement stabilized soils show that the cement stabilized soils do not obey the associated flow rule at high confining pressures. The parametric study shows that the influence of cementation increases the brittle nature and the bearing capacity of treated clay. In addition the results show that proposed finite element implementation has the ability to illustrate key features of the cement stabilized clay.

This paper presents an implementation of an elasto‐plastic constitutive model, based on the extended critical state concept, for cement stabilized soils into a finite element programme, which has been identified as an important and challenging topic in computational geomechanics. This implementation is useful in solving boundary value problems in geomechanics involving cement stabilized soils, incorporating key characteristics of these soils.

In this paper, nanocomposites are synthesised with Tunisian natural clay which has the advantage of being inexpensive. In fact, it is simply a mixture of several sorts of clays (kaolinite, dolomite, calcite, illite, and quartz). This clay has been cleaned, purified, dried, and steered with polyacrylate resin which is actually used in the textile field for several types of other applications, such as comfort, elasticity or impermeability. The samples have been examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to observe their compositions and ensure the formation of the nanocomposites .The mixture resin/clay is deposited onto 100% cotton fabric and tested by using a PASOD device that measures the necessary voltage to maintain the temperature difference between the inside and the outside of the fabric which is equal to 20°C. The enhancement of the fabric thermal insulation is noticed by calculating the difference in temperature between the inside and the outside of the fabric. The coating which is a nanocomposite PAC/clay has been modelled which proves that it is a Hamiltonian model as the clay percentages are superior to 4% when the clay dispersion and the free-volume are calculated.

It is well-known that consolidation rate of prefabricated vertical drain (PVD)-installed ground is closely related to the discharge capacity of PVD, which decreases with an increase in effective stress. This paper aims to present consolidation behaviors of PVD-improved ground considering a varied discharge capacity of PVD.

A simple equivalent vertical hydraulic conductivity (k′_ve method) was proposed in plane strain numerical analysis, in which the effect of decreased discharge capacity with depth was considered. Numerical analysis was applied to analyze field behaviors of test embankment of soft mucky deposit.

Finite element method results indicated that consolidation behaviors of PVD-improved soil with a nonlinear distribution of discharge capacity with depth were in a good agreement with the observed field behaviors, compared with those with a constant discharge capacity and a linear distribution of discharge capacity. At a given time and depth, the consolidation rate in the case of discharge capacity with a nonlinear distribution is lower than that of a linear or constant distribution.

A geotechnical engineer could use the proposed method to predict consolidation behaviors of drainage-installed ground.

Consolidation behaviors of PVD-installed ground could be reasonably predicted by using the proposed method with considering effect of discharge capacity reduction.

This paper proposes a unified original general framework, designed to theoretically develop and to extremely easily implement elastoplastic constitutive laws defined in the so called two-invariants space, both in small and finite strain regime.

A general return mapping algorithm is proposed, and particularly a standard procedure is developed to compute the two algorithmic tangent operators, required to solve the Newton–Raphson scheme at the local and global level and thus cast the elastoplastic algorithm within a FEM code.

This work demonstrates that the proposed procedure is fully general and can be applied whatever is the elastic law, the yield surface, the plastic potential function and the hardening law. Several numerical examples are reported, not only to demonstrate the accuracy and robustness of the algorithm, but also explain how to use this general algorithm also in other applications.

The proposed algorithm and its numerical implementation into a FEM code is new and original. The usefulness and the value of the algorithm is twofold: (1) it can be implemented in a small and finite strain simulation FEM code, in order to handle different types of constitutive laws in the same modular way, thus fully leveraging on modern object-oriented coding approach; (2) it can be used as a framework to develop (and then to implement) new constitutive models, since the researcher can simply define the relevant functions (and its main derivatives) and automatically get the numerical algorithm.

Illustrated with the case of Renault-Dacia in Romania we aim to give insights in how and why foreign car makers contribute to upgrading. In addition, we analyse the spatial implications of this process for different parts of the value chain.

We divide the investments of Renault in Romania in different stages. In each stage we analyse in which functions the car maker invests, in which place, why, and which implications this has for upgrading. The empirical data stems from in-depth interviews with Renault managers, engineers and designers in Romania and in France and from further corporate information, including annual reports, press releases and web sites.

We show that Renault contributes to all types of upgrading, starting with product and process upgrading in the first stages, while in later stages it also invests in functional upgrading. It does not only upgrade its own subsidiary, but also suppliers and knowledge institutes. Concerning the value chain, we see that Renault keeps the basic research and control functions in the home base, while it performs all other functions in Romania as well.

Via the concept of upgrading analysed in various investments stages we provide managers insights in which parts of the value chain they should invest when entering a new market.

Although the case Renault-Dacia is relatively well known as an example of a low cost strategy, this article analyses the investment strategy in different stages in time and takes into account various parts of the value chain and upgrading.