LCI databases sensitivity analysis of the environmental impact of the injection molding process

During the last decades, society’s concern for the environment has increased. Specific tools like the Life Cycle Assessment (LCA), and software and databases to apply this method have been developed to calculate the environmental burden of products or processes. Calculating the environmental impact of plastic products is relevant as the global plastics production rose to 288 million tons in 2012. Among the different ways of processing plastics, the injection molding process is one of the most used in the industry worldwide. In this paper, a sensitivity analysis of the environmental impact of the injection molding process has been carried out. In order to perform this study, the EcoInvent database inventory for injection molding, and the data from which this database is created, have been studied. Generally, when an LCA of a product is carried out, databases such as EcoInvent, where materials, processes and transports are characterized providing average values, are used to quantify the environmental impact. This approach can be good enough in some cases but in order to assess a specific production process, like injection molding, a further level of detail is needed. This study shows how the final results of environmental impact differ for injection molding when using the PVC’s, PP’s or PET’s data. This aspect suggests the necessity of studying, in a more precise way, this process, to correctly evaluate its environmental burden. This also allows us to identify priority areas and thereby actions to develop a more sustainable way of manufacturing plastics

Environmental impact analysis of the injection molding process: Analysis of the processing of high-density polyethylene parts

This paper studies the environmental impact of the injection molding process by carrying out a life cycle assessment. A review of how EcoInvent''s Life Cycle Inventory database characterizes this process has been conducted, and a new methodology based on that analysis has been carried out. Aspects such as the infrastructure of the factory or waste treatment are part of the environmental impact of the injection molding process, but the most significant factor is electricity consumption; therefore, electricity consumption measurements of the process have been performed. This environmental analysis has been applied to the processing of several parts made of high-density polyethylene, which have been characterized by measuring the electricity consumption. As a consequence of this work, it has been proven that electricity consumption can be used as an injection molding machine selection criteria, from an environmental standpoint, as it produces the highest environmental burden of the process

Evolution algebras, automorphisms, and graphs

The affine group scheme of automorphisms of an evolution algebra e with e 2 is shown to lie in an exact sequence ¿ D ¿ Aut(E) ¿ S, where D, diagonalizable, and S, constant, depend solely on the directed graph associated to e. As a consequence, the Lie algebra of derivations Der(e) (with e 2 = E)is shown to be trivial if the characteristic of the ground field is 0 or 2, and to be abelian, with a precise description, otherwise

Composition algebras with large derivation algebras

The finite dimensional flexible composition algebras include the Hurwitz algebras (composition algebras with unit element), but also other interesting classes of algebras: the para-Hurwitz and the Okubo algebras. The above mentioned algebras present many symmetries, and this is reflected in their large derivation algebras. In the present paper we study the opposite question: What can be said about the composition algebras if we have some information about their derivation algebras? Our main result is the classification of all the composition algebras with such large derivation algebras. © 1997 Academic Press

Clifford Algebras as Twisted Group Algebras and the Arf Invariant

Some connections between quadratic forms over the field of two elements, Clifford algebras of quadratic forms over the real numbers, real graded division algebras, and twisted group algebras will be highlighted. This allows to revisit real Clifford algebras in terms of the Arf invariant of the associated quadratic forms over the field of two elements, and give new proofs of some classical results

Cross products, invariants, and centralizers

An algebra V with a cross product x has dimension 3 or 7. In this work, we use 3-tangles to describe, and provide a basis for, the space of homomorphisms from V-circle times n to V-circle times m that are invariant under the action of the automorphism group Aut(V, x) of V, which is a special orthogonal group when dim V = 3, and a simple algebraic group of type G(2) when dim V = 7. When m = n, this gives a graphical description of the centralizer algebra End(Aut(v, x))(V-circle times n), and therefore, also a graphical realization of the Aut(V, x)-invariants in V-circle times 2n equivalent to the First Fundamental Theorem of Invariant Theory. We show how the 3-dimensional simple Kaplansky Jordan superalgebra can be interpreted as a cross product (super)algebra and use 3-tangles to obtain a graphical description of the centralizers and invariants of the Kaplansky superalgebra relative to the action of the special orthosymplectic group

Maximal finite abelian subgroups of E-8

The maximal finite abelian subgroups, up to conjugation, of the simple algebraic group of type E-8 over an algebraically closed field of characteristic 0 are computed. This is equivalent to the determination of the fine gradings on the simple Lie algebra of type E-8 with trivial neutral homogeneous component. The Brauer invariant of the irreducible modules for graded semisimple Lie algebras plays a key role

Textile injection process characterisation by means of a spiral mould

New developments are being carried out within the injection moulding field, such as gas injection, bi-injection, co-injection, sequential injection, compression injection or textile injection processes. These techniques require new developments as they highly modify design and process conditions. In this work, the influence over the plastic material flow of the introduction of different film textiles into the mould is measured. A specific measurement system consisting of a monitorised spiral mould with pressure sensors has been used to measure the influence of different tissues over the mould pressures. As an application of this measurement system, a viscous model is generated to characterise the rheological behaviour of the thermoplastic and textile joint. The viscous model obtained is applied on a conventional CAE tool for the simulation of textile injection pressure results for the different film textiles analysed

Analysis of self-lubrication enhancement via PA66 strategies: Texturing and nano-reinforcement with ZrO2 and graphene

Graphene nanoflakes and zirconium dioxide (ZrO2) were added to polyamide 66-based composites with glass fibre in order to improve their self-lubricating properties and make them suitable for high-performance bearing applications. The influence of texturing the surfaces was also investigated. The tribological behaviour was analysed for different combinations of hybrid polymeric composites, percentages of additive, and texturing geometries. The results show that the lowest low friction coefficients are obtained for PA66 + 30GF with 5% graphene. Worn surfaces, analysed by scanning electron microscopy and optical microscopy confirm the enhancement of the tribological properties with the addition of graphene. Texturing results under dry lubrication are not relevant for tribological purposes

The influence of environmental conditions on the dimensional stability of components injected with PA6 and PA66

The design of assembly components requires special attention to aspects related to their dimensions to ensure their functionality. The goal of this paper is to analyse the influence of case-based environmental conditions, including extreme hydrothermal conditions, on the dimensional stability of a component made from different polyamides throughout the component''s working life. The results support the conclusion that components made from PA6 have a higher capacity to absorb humidity than those made from PA66 and, on the other hand, a higher capacity to lose this humidity, which implies a more significant effect on the average error in the dimensions considered (12% for PA6 in comparison to 3% for PA66). With regard to assembly dimensions, components remain within dimensional tolerances under average and extreme humidity conditions and average temperature conditions. Components injected with P66 are more stable for all of the situations analysed