Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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Polycarboxylate Based Superplasticizers as Dispersant Agents for Exfoliated Graphene Nanoplatelets Reinforcing Cement Based Materials

Graphene nanoplatelets (GNPs) are considered one of the most advanced nanomaterials that hold the promise of providing multifunctional characteristics to the cementitious matrix. To effectively employ the GNPs as a nanoreinforcement, their uniform dispersion within the matrix must be achieved. The present study investigates the efficiency of four different polycarboxylate based superplasticizers, which are fully compatible with cement-based materials, to be exploited as GNPs dispersant agents. Exfoliated GNPs were selected that had a quite small diameter/lateral size of ~5 µm. The dispersing efficiency of the superplasticizers was investigated experimentally by measuring the electrical resistivity of the resulting nanocomposites. A discussion explaining the dispersing mechanism of these types of surfactants is provided. The use of a superplasticizer in conjunction with ultrasonic energy application was found to be necessary to properly disperse the GNPs. The results prove that the polycarboxylate based superplasticizers can be employed to promote the GNPs uniform distribution in cementitious materials. The polycarboxylate ester superplasticizer showed poor results, while the polycarboxylate polymer superplasticizers were found to be more effective to uniformly disperse the GNPs

Processing traits of European catfish (Silurus glanis Linnaeus, 1758) from outdoor flow-through and indoor recycling aquaculture units

The quality of fish cultured using recycling units may differ from that of fish from outdoor farming units due to a range of deviating environmental determinants. This applies not only to flesh quality but also to morphological (processing) traits. This study evaluates processing yields of sibling fish cultured in two different farming units: (i) an outdoor pond aquaculture system with a flow-through regime (24.6 ± 0.2°C), and (ii) indoor tanks using a recirculation aquaculture system (RAS; 26.0 ± 1.0°C). Clear differences were observed in the most important processing traits, i.e. skinned trunk and fillet yields, which were both significantly higher (P 0.05) in males

Nanomaterials in Cementitious Composites: An Update

This review is an update about the addition of nanomaterials in cementitious composites in order to improve their performance. The most common used nanomaterials for cementitious materials are carbon nanotubes, nanocellulose, nanographene, graphene oxide, nanosilica and nanoTiO2. All these nanomaterials can improve the physical, mechanical, thermal and electrical properties of cementitious composites, for example increase their compressive and tensile strength, accelerate hydration, decrease porosity and enhance fire resistance. Cement based materials have a very complex nanostructure consisting of hydration products, crystals, unhydrated cement particles and nanoporosity where traditional reinforcement, which is at the macro and micro scale, is not effective. Nanomaterials can reinforce the nanoscale, which wasn’t possible heretofore, enhancing the performance of the cementitious matrix

Cement Composites with Graphene Nanoplatelets and Recycled Milled Carbon Fibers Dispersed in Air Nanobubble Water

The individual effect of nano- and micro-carbon-based fillers on the mechanical and the electrical properties of cement paste were experimentally examined in this study. The objective of the study was to separately examine the effects of size and morphology (platelets and fibers) of nano- and micro-reinforcement. Three different sizes of Graphene Nanoplatelets (GNPs), at contents of 0.05% and 0.20% and recycled milled carbon fibers (rCFs), at various dosages from 0.1–2.5% by weight of cement, were incorporated into the cementitious matrix. GNPs and rCFs were dispersed in water with air nanobubbles (NBs), an innovative method that, compared to common practice, does not require the use of chemicals or high ultrasonic energy. Compressive and bending tests were performed on GNPs- and rCFs-composites. The four-wire-method was used to evaluate the effect of the conductive fillers on the electrical resistivity of cement paste. The compressive and flexural strength of all the cementitious composites demonstrated a considerable increase compared to the reference specimens. Improvement of 269.5% and of 169% was observed at the compressive and flexural strength, respectively, at the GNPs–cement composites incorporating the largest lateral size GNPs at a concentration of 0.2% by weight of cement. Moreover, the rCFs–cement composites increased their compressive and flexural strength by 186% and 210%, respectively, compared to the reference specimens. The electrical resistivity of GNPs- and rCFs-composite specimens reduced up to 59% and 48%, respectively, compared to the reference specimens, which proves that the incorporation of GNPs and rCFs can create a conductive network within the cementitious matrix

Nanomaterials in Cementitious Composites: An Update

This review is an update about the addition of nanomaterials in cementitious composites in order to improve their performance. The most common used nanomaterials for cementitious materials are carbon nanotubes, nanocellulose, nanographene, graphene oxide, nanosilica and nanoTiO2. All these nanomaterials can improve the physical, mechanical, thermal and electrical properties of cementitious composites, for example increase their compressive and tensile strength, accelerate hydration, decrease porosity and enhance fire resistance. Cement based materials have a very complex nanostructure consisting of hydration products, crystals, unhydrated cement particles and nanoporosity where traditional reinforcement, which is at the macro and micro scale, is not effective. Nanomaterials can reinforce the nanoscale, which wasn’t possible heretofore, enhancing the performance of the cementitious matrix