Aino Helle

Bio: Aino Helle is an academic researcher from VTT Technical Research Centre of Finland. The author has contributed to research in topics: Lubrication & Prognostics. The author has an hindex of 6, co-authored 10 publications receiving 152 citations.

Adhesion and tribological properties of hydrophobin proteins in aqueous lubrication on stainless steel surfaces

Abstract: Macroscale tribological properties of hydrophobin layers bound on stainless steel surfaces were investigated in an aqueous environment. Emphasis was on boundary lubrication because water easily fails in hydrodynamic lubrication due to its low viscosity. We studied the affinities of two different proteins, HFBI and FpHYD5, on stainless steel and their ability to bind water at the surface by combining quartz crystal microbalance (QCM-D) and ellipsometry. Both proteins contained an adhesive hydrophobic domain, but FpHYD5 also had a very strongly hydrating carbohydrate structure attached to it. The lubrication properties of the proteins were studied with two different methods, pin-on-disc (POD) (stainless steel vs. stainless steel) and circular translation pin-on-disc (CTPOD) (UHMWPE vs. stainless steel). It was observed that both hydrophobins could adhere to the stainless steel surface and form highly hydrated layers. Both proteins reduced friction and wear of the sliding contact between two stainless steel surfaces. With UHMWPE against stainless steel, the hydrophobins prevented the polyethylene transfer to the counterface. The lowest coefficient of friction (COF) 0.13 was observed when FpHYD5 hydrophobins were employed in pure water. On the other hand, the lowest wear was observed when FpHYD5 proteins were added in a 50 mM sodium acetate buffer. Increasing the water content and loosening the hydrophobin film structure on the stainless steel surface led to a reduction in friction and wear.

Prognostics for industrial machinery availability

Abstract: In our society, a trend for increasing interest in and higher priority given to reliability, maintenance, safety and security can be observed. The technical development offers every day new and more advanced tools to achieve this. The challenge to manage to predict failures and disturbances, and to estimate the remaining lifetime of components, mechanical systems and integrated systems is a very difficult one. On this route we are today only taking the first steps. For the next steps, deepening of our knowledge in many of the technological areas involved is needed, and in addition it is necessary to find holistic approaches and methodologies to integrate the different techniques involved. In this article we will present a method to integrate the tribological knowledge into monitoring and diagnostics techniques, show how the step from diagnostics to prognostics can be taken, outline a new European concept for IT-based maintenance and show the benefit of networked global diagnostic centres.

Biomimetic approach to water lubrication with biomolecular additives

Abstract: The aim of this study is to find a connection between mechanical engineering and biotechnology by utilizing biomimetics in lubrication. The objective is to improve boundary lubrication by biomolecules in water-based systems. Proteins were used because they can form films and multilayers on the surfaces and thus prevent direct contact between them. In this study, hydrophobin and albumin proteins are studied as additives to enable water lubrication.

Advanced Materials through Assembly of Nanocelluloses.

Abstract: There is an emerging quest for lightweight materials with excellent mechanical properties and economic production, while still being sustainable and functionalizable. They could form the basis of the future bioeconomy for energy and material efficiency. Cellulose has long been recognized as an abundant polymer. Modified celluloses were, in fact, among the first polymers used in technical applications; however, they were later replaced by petroleum-based synthetic polymers. Currently, there is a resurgence of interest to utilize renewable resources, where cellulose is foreseen to make again a major impact, this time in the development of advanced materials. This is because of its availability and properties, as well as economic and sustainable production. Among cellulose-based structures, cellulose nanofibrils and nanocrystals display nanoscale lateral dimensions and lengths ranging from nanometers to micrometers. Their excellent mechanical properties are, in part, due to their crystalline assembly via hydrogen bonds. Owing to their abundant surface hydroxyl groups, they can be easily modified with nanoparticles, (bio)polymers, inorganics, or nanocarbons to form functional fibers, films, bulk matter, and porous aerogels and foams. Here, some of the recent progress in the development of advanced materials within this rapidly growing field is reviewed.

Plant seed mucilage as emerging biopolymer in food industry applications

Abstract: The demand for sustainable, eco-green and minimally processed food ingredients of innate technological (structuring, texturising, stabilising) and functional potential is on the growth. Plant seed mucilage (PSM) constitutes a polysaccharide hydrocolloid of particular physicochemical and structure conformational diversity which endows a broad range of functional and health relevant aspects. Many studies have demonstrated the peculiar structuring and stabilising role of crude and fractionated PSM in model and real food matrices. In addition, PSMs intake through the orogastrointestinal route has been associated with several health benefits such as modulation of postprandial glycaemic and insulinaemic response, hyperlipidaemia counteracting, satiety enhancement, regulation of gut microbiota function. This concise review discusses the most recent advancements in the field of PSM extraction and characterisation as well as their exploitation as alternative hydrocolloids for food and nutraceutical industry applications.

E-maintenance: review and conceptual framework

Abstract: E-maintenance is an emerging concept generally defined as “a maintenance management concept whereby assets are monitored and managed over the Internet”. Nevertheless a lot of complementary definitions exists in which are introduced the principles of collaboration, knowledge, intelligence ... A consensus is not approved and the number of references and work is huge without a unique repository to ensure consistency. Consequently the aim of this research and review note is to define more precisely the emerging concept of e-maintenance and then to propose and discuss a conceptual e-maintenance framework based on Zachman framework. Such a framework can facilitate a widespread understanding of e-maintenance and provide useful guidance for supporting e-maintenance deployment through services, processes, organisation and infrastructure. It should be served as reference for inventory all the work related to this topic. Thus, a first relevance of the framework is shown by positioning, in a coherent way, most of the well known e-maintenance contributions and platforms

Structure of native cellulose microfibrils, the starting point for nanocellulose manufacture

Abstract: There is an emerging consensus that higher plants synthesize cellulose microfibrils that initially comprise 18 chains. However, the mean number of chains per microfibril in situ is usually greater than 18, sometimes much greater. Microfibrils from woody tissues of conifers, grasses and dicotyledonous plants, and from organs like cotton hairs, all differ in detailed structure and mean diameter. Diameters increase further when aggregated microfibrils are isolated. Because surface chains differ, the tensile properties of the cellulose may be augmented by increasing microfibril diameter. Association of microfibrils with anionic polysaccharides in primary cell walls and mucilages leads to in vivo mechanisms of disaggregation that may be relevant to the preparation of nanofibrillar cellulose products. For the preparation of nanocrystalline celluloses, the key issue is the nature and axial spacing of disordered domains at which axial scission can be initiated. These disordered domains do not, as has often been suggested, take the form of large blocks occupying much of the length of the microfibril. They are more likely to be located at chain ends or at places where the microfibril has been mechanically damaged, but their structure and the reasons for their sensitivity to acid hydrolysis need better characterization.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.