Effect of Processed Volcanic Ash as Active Mineral Addition for Cement Manufacture

In the last quarter of 2021, there was a very significant eruption of the Cumbre Vieja volcano on the island of La Palma, belonging to the Canary Islands, Spain. It generated a large amount of pyroclastic volcanic materials, which must be studied for their possible applicability. This work studies the properties and applicability of the lava and volcanic ash generated in this process. The need for reconstruction of the areas of the island that suffered from this environmental catastrophe is considered in this study from the point of view of the valuation of the waste generated. For this purpose, the possibility of using the fine fraction of ashes and lava as a supplementary cement material (SCM) in the manufacture of cement is investigated. The volcanic material showed a chemical composition and atomic structure suitable for replacing clinker in the manufacture of Portland cement. In this study, the cementing and pozzolanic reaction characteristics of unprocessed volcanic materials and those processed by crushing procedures are analysed. To evaluate the cementitious potential by analysing the mechanical behaviour, a comparison with other types of mineral additions (fly ash, silica fume, and limestone filler) commonly used in cement manufacture or previously studied was carried out. The results of this study show that volcanic materials are feasible to be used in the manufacture of cement, with up to a 22% increase in pozzolanicity from 28 to 90 days, showing the high potential as a long-term supplementary cementitious material in cement manufacturing, though it is necessary to carry out crushing processes that improve their pozzolanic behaviour

Geranium's response to compost based substrates

8 páginas, 2 figuras, 3 tablas, 10 referencias.-- International Symposium on Composting and use of Composted Materials for Horticulture, celebrado del 5-11 de abril 1997, en Ayr, Scotland, United Kingdom.The effects of compost based substrates on growth and nutrition of geranium (Pelargonium zonale cv Lucky Break F2) were investigated. Substrates of manure compost, cotton gin trash compost, municipal solid waste compost and pine bark utilized as potting media for domestic use, produced an underdevelopment of geranium plants with respect to the control. This behaviour is related to the inferior physical properties of the compost-based potting media, nitro gen immobilization due to the high C/N ratio of pine bark, and probably lack of available phosphorus originated by high calcium and high pH of the compost-based media. Nitrogen fertilization and a longer period of cultivation diminished the differences between plants grown in the control and in compost-based media. Plants grown in compost mixtures which were rich in K showed K and Ca leaf contents closer to the optimum range than did control plants.This work was supported by the Agencia de Medio Ambiente of the Junta de Andalucía and by Fertilizantes Orgánicos Melguizo, S. L.Peer reviewe

Nitrogen mineralization in soils amended with organic by-products of olive oil and sugarbeet processing industries

Mineralization of organic-N supplied te two different types of soils by an alpechín (olive-oil mill waste water)-compost and a beet vinasse after three consecutive years was studied. Results were compared with those obtained for a mineral fertilizer treatment and a control (unfertilized). N-mineralization can be described by a first order kinetic model. Both organic residues produced an important increase in me organic-N loading of the soils which is slowly released over a time.Peer Reviewe

Alkali-Activated Stainless Steel Slag as a Cementitious Material in the Manufacture of Self-Compacting Concrete

This work develops the manufacture of self-compacting concrete (SCC) with 50% cement reduction. As an alternative binder to cement, the viability of using an alkali-activated combination of stainless steel slag (SSS) and fly ash (FA) has been demonstrated. SSS was processed applying three different treatments. Binders were manufactured mixing 35% SSS with 65% FA, as precursors, and a hydroxide activating solution. This binder was replaced by the 50% cement for the manufacture of SCC. The results obtained show good mechanical properties and durability. The study shows a reduction in the use of cement in the manufacture of SCC reusing two wastes

Mimicking the extracellular matrix – a biomaterials approach to inhibit tissue fibrosis

Epithelial tissue is marked by the presence of a specialized, highly cross-linked, sheet-like extracellular matrix, the basement membrane. Tissue-invasive events, such as the epithelial-to-mesenchymal transition (EMT) - a key event in gastrulation, tissue fibrosis and cancer metastasis – are characterized by irreversible structural changes of the basement membrane through proteolytic processing by matrix metalloproteinases (MMPs). We have recently reported a previously unidentified laminin fragment that is released during EMT by MMP2 and that modulates key EMT-signalling pathways. Specifically, interaction of the laminin fragment with α3β1-integrin triggers the down-regulation of MMP2 expression, thereby constituting a cell-basement membrane-cell feedback mechanism. Inhibiting MMPs has been proposed as a strategy to prevent pathological cell migration and basement membrane breakdown in the course of EMT. Here, we explore this cell-matrix-cell feedback mechanism to target pathological EMT in the course of tissue fibrosis. We present an electrospun biomaterial that is functionalized with the recombinant laminin fragment and that can be directly interfaced with epithelial tissue to interfere with EMT pathways and inhibit MMP2 expression and activity in vitro and in vivo. We demonstrate how interaction of the functionalized synthetic membrane with peritoneal tissue inhibits mesothelial EMT in a mouse model of TGFβ-induced peritoneal fibrosis by decreasing active MMP2 levels, and propose a mechanism of how the laminin fragment acts downstream of α3β1-integrin in epithelial cells, after it is released from the basement membrane

Eco-Efficient Cement-Based Materials Using Biomass Bottom Ash: A Review

In recent years the use of biomass for electricity generation in thermal and cogeneration plants has increased worldwide because it is an environmentally clean fuel whose impact measured in greenhouse gas emissions is practically zero. However, biomass bottom ash, a waste produced during combustion, has also increased considerably, which has both a negative economic and environmental impact, due to landfill transport and management of this by-product. Although biomass bottom ash has potential characteristics for application in the manufacture of construction materials, its full-scale application is difficult because of the wide range in physicochemical properties, depending on the type of biomass burned, such as wood residue, olive waste, waste paper sludge, cocoa shell, etc., and the type of combustion process in the plant. This study reviews the influence on the physicochemical properties, mechanical behavior, and durability of different cement-based materials, such as mortars, concrete, and cement-treated granular material, manufactured from biomass bottom ash. The previous studies demonstrate the feasibility of substituting natural materials for biomass bottom ash in cement-based materials, presenting adequate mechanical behavior and durability properties to comply with the required technical specifications in different building materials

Considerations on the low-pressure exhaust gas recirculation system control in turbocharged diesel engines

Although high-pressure exhaust gas recirculation has been commonly used in turbocharged diesel engines for controlling the NOx formation, recent advances in after-treatment and material technology make possible using a low-pressure architecture, which recirculates the exhaust gas upstream the compressor. This brief article presents a basic study of control aspect related to the low-pressure architecture, emphasising the similarities and differences with the highpressure system. Data from experimental tests with both configurations and from a one-dimensional wave action model simulations are combined for the analysis of the input–output paring, linearity and the transient performance of both systems.This research has been partially financed by the Spanish Ministerio de Economia y Competitividad, through project IPT-370000-2010-022 'Investigacion y desarrollo de tecnologias de EGR adaptadas a las nuevas arquitecturas y requerimientos de refrigeracion en motores diesel sobrealimentados para automocion (HIREFIRE)'.Lujan Martinez, JM.; Guardiola García, C.; Plá Moreno, B.; Cabrera López, P. (2014). Considerations on the low-pressure exhaust gas recirculation system control in turbocharged diesel engines. International Journal of Engine Research. 15(2):250-260. https://doi.org/10.1177/1468087413485209S25026015

Feasible Use of Recycled Concrete Aggregates with Alumina Waste in Road Construction

The management of different industrial by-products, such as recycled aggregates from construction and demolition waste and alumina by-products, as well as the reduction of landfill deposits by incorporating these products in a second life cycle, were the focus of this work. The aim of this study was to demonstrate the technical viability of using these waste and by-product as a material for road pavement base layers. For this purpose, a real-scale application was carried out, and the behavior of three types of materials, applied on a section of an experimental road under real vehicle traffic conditions, was studied and compared. Three materials were used in these sections applied in the road sub-bases. First, a control material composed of a type of artificial gravel was used to be compared with the rest of materials; the second material was composed of recycled aggregates, and the third was composed of a mix of recycled aggregates and alumina waste. The results concluded that the effectiveness of the sections built using recycled aggregates and alumina waste was very positive and similar those constructed using natural aggregates

Feasibility of Using Nanosilanes in a New Hybrid Stabilised Soil Solution in Rural and Low-Volume Roads

The application of new materials for soil stabilisation is a growing field of study in recent years. In this work, the effect of two types of silica-based nanomaterials combined with binders (quicklime and cement) are studied to stabilise soils and form structural layers for rural and low volume roads. The physical and chemical properties of the materials have been determined, as well as the mechanical behaviour of the stabilised soil. Three hybrid stabilised soil sections have been designed using a multilayer elastic model, executed at full scale and measuring the evolution of their properties in the medium to short term. The results show that the application of silica-based nanomaterials and two types of binders on the tread layers provide high structural stability and good behaviour of the sections