Optimisation Potential

Another nonnegligible aspect which may have a significant influence in the environmental assessment of bioplastics, notably in comparative studies with other materials, is linked to their optimisation potential. 

Bioplastics are still in their early stage of development [35]. They are produced on a small scale or in singular facilities, meaning that transport, conversion, product design and final disposal are not optimised. They are, however, quite often compared with mature materials whose life cycles have been optimised over several decades. This may lead to a biased comparison. The optimisation and improvement potential for bioplastics is huge and includes  

The above points are not immediately evident when performing an LCA of bioplastics. In general, the life cycle-based comparison between novel and mature products does not take this basic difference into account. As remarked by European Bioplastics, projections for improvement should be made and included in LCA studies. Besides, new materials and products, such as bioplastics, are often closely scrutinised while many existing products on the shelf are far less thoroughly examined. Within their life cycle, bioplastics are often put under the microscope while the impact of, e.g., oil or gas production is often modelled using fewer details, for instance, using data from generic databases. 

LCA does not provide universally valid answers, but can provide answers to specific and well-formulated questions. The environmental performance of bioplastic applications depend upon many different parameters. These include the type of bioplastics used, the raw materials which they originate from, the production and conversion technology, the transport means and distances, and the type of application, as well as the waste collection and disposal or recycling system. As remarked also by European Bioplastics, it is not possible to make generalisations such as bioplastics are better or worse than other materials . 

LCA is a complex tool which requires expertise and thorough knowledge. The methodology has been increasingly standardised over the last few years, but a certain degree of subjectivity still exists in the application and may lead to contradictory or misleading results. 

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Jorgensen et al. has developed a series of united atom intermolecular potential functions based on multiple Monte Carlo simulations of small molecules [10-23]. Careful optimisation of these functions has been possible by fitting to the thermodynamic properties of the materials studied. Combining these OPLS functions (Optimised Potentials for Liquid Simulation) with the AMBER intramolecular force field provides a powerful united-atom force field [24] which has been used in bulk simulations of liquid crystals [25-27],... 

There is still freedom in the choice of atomic orbitals used in Eq. (50). For instance, one can use fixed atomic orbitals, which eliminates the (sometimes costly) orbital optimisation. One can also use fully optimised, potentially delocalised orbitals in the spin-coupled / Coulson-Fischer sense. Finally, one can use real atomic orbitals by limiting each orbital to its own atom. This often gives a clearer physical picture of chemical bonding. It generates for instance optimal hybrids [9,10]. 

The requirement for shortening the pharmaceutical discovery process caused the integration of pharmacokinetic and drug development efforts into earlier discovery to rapidly focus on molecules with increased optimisation potential. It is mandatory to initiate time-consuming optimisation programs only for those chemical series which show a potential to be convertible into drug molecules. 

In contrast chemical and electrolytic polishing enables a smooth level surface to be produced without any residual stress being developed in the surface because the surface is removed by dissolution at relatively low chemical potential and at relatively low rates is such a way that metallic surface asperities are preferentially removed. For this to be most effective the solution properties must be optimised and the pretreatment must leave an essentially bare metal surface for attack by the electrolyte. 

Computer simulations therefore have several inter-related objectives. In the long term one would hope that molecular level simulations of structure and bonding in liquid crystal systems would become sufficiently predictive so as to remove the need for costly and time-consuming synthesis of many compounds in order to optimise certain properties. In this way, predictive simulations would become a routine tool in the design of new materials. Predictive, in this sense, refers to calculations without reference to experimental results. Such calculations are said to be from first principles or ab initio. As a step toward this goal, simulations of properties at the molecular level can be used to parametrise interaction potentials for use in the study of phase behaviour and condensed phase properties such as elastic constants, viscosities, molecular diffusion and reorientational motion with maximum specificity to real systems. Another role of ab initio computer simulation lies in its interaction... 

One of the disadvantages of the method is that one must determine the smoothing parameter by optimisation. When the smoothing parameter is too small (Fig. 33.16a) many potential functions of a learning class do not overlap with each other, so that the continuous surface of Fig. 33.15 is not obtained. A new object u may then have a low membership value for a class (here class K) although it clearly belongs to that class. An excessive smoothing parameter leads to a too flat surface (Fig. 33.16b), so that discrimination becomes less clear. The major task of the... 

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