Isodecyl acrylate - olive oil copolymers as potential biodegradable additive for lubricating oil

The use of greener additives based on vegetable oils in the formulation of bio-lubricant has attracted considerable interest due to their biocompatibility and enhanced multifunctional performances compared to conventional additives. Working in this direction and in an anticipation of introducing biodegradability in to the acrylate based additive system, copolymers of isodecyl acrylate with olive oil have been synthesized by thermal method using BPO (benzoyl peroxide) as radical initiator. Characterization of the prepared polymers has been performed by spectral (NMR, IR), and SEC-GPC analysis. Performance evaluation of the polymers as pour point depressant (PPD), and viscosity modifier/viscosity index improver (VII) in different base oils (mineral) have been performed by standard ASTM methods. Biodegradability of the prepared additives was tested against fungal pathogens and microorganisms by disc diffusion (DD) method and by soil burial test (SBT) method respectively. Thermal stability of each of them has been evaluated and included. The multifunctional performances have been compared and reported. The copolymers showed potential multifunctional additive performance as viscosity modifier and pour point depressant along with excellent biodegradability.     

Region-by-region modeling of laminated composite plates

Several plate models have been proposed in the literature for the analysis of laminated plates. These are based either on an equivalent through-thickness formulation or a layerwise formulation. It is shown in the literature that while the equivalent models are economical, the layerwise models are expensive but are also more accurate, especially with respect to the transverse stresses. Generally, the same model is used throughout the domain. The current study addresses the issue of economical and accurate computation of local stresses, strains and displacements (as well as global quantities) using combinations of layerwise, equivalent or intermediate models in various regions of the domain. A region-by-region modeling strategy is presented for a chosen general family of equivalent, intermediate and layerwise models. The proposed strategy allows the user to put any model (of any order in the thickness direction) in any desired region of interest. The effectiveness of the strategy is demonstrated through numerical examples. It is shown that this approach can significantly reduce computational cost and can also lead to good resolution of the local stress and displacement fields for domains with unsymmetric laminae, cut-outs, local damage, corner edges, sudden transition of boundary conditions and material.     

Flowing to the East—— Small Hydro in Developing Countries

While the growth of small hydro has slowed in Europe, things look very different in Asia. The region accounts for two-thirds of the world＇s hydro capacity, and far from slowing down, it is enjoying robust growth. Simon Taylor, Drona Upadhyay and Maria Laguna write this review.     

Computer simulation of membrane processes: ultrafiltration and dialysis units

An algorithm for computer simulation of membrane processes such as ultrafiltration and dialysis has been developed using a simplified finite volume approach. The technique used is slightly different from the standard finite difference, finite volume and finite element methods where all the parameters are considered at fixed nodal points. In the present approach the entire flow chamber is divided into a large number of volume elements and each element is considered to be an independent unit (similar to finite volume method). All mass flux and velocity components are calculated at the boundaries whereas concentration is considered at the center of the element. Thus, unlike FDM, FVM, and FEM, in the present approach nodal points for velocity and concentration are different. It has been observed that this method is more accurate and fast and requires less computational effort.