Evaluation of the Effect of Crystallization Additives on the Durability of Cement Composites

2017 ◽  
Vol 908 ◽  
pp. 15-20 ◽  
Author(s):  
Ámos Dufka ◽  
Tomáš Melichar
Keyword(s):  
Service Life ◽  
Porous Structure ◽  
Comprehensive Analysis ◽  
Cement Composites ◽  
Chemical Analyses ◽  
Self Compacting Concrete ◽  
Physico Chemical

The paper deals with a comprehensive analysis of the influence of applied crystallization additives on the service life of self-compacting concrete (SCC), specifically when exposed to the effects of chemically aggressive environments. Attention is focused not only on the influence of a crystallization additive on the characteristics of the capillary porous structure of SCC, but mainly on its effects in terms of the long-term service life of self-compacting concrete. The effects of individual types of aggressive environments are evaluated on the basis of a set of physico-mechanical and physico-chemical analyses.

Effect of Crystallization Additives on Durability of Cement Composites in Aggressive Environments

2021 ◽  
Vol 321 ◽  
pp. 89-96
Author(s):  
Ámos Dufka ◽  
Šárka Keprdová ◽  
Tomáš Melichar
Keyword(s):  
Acid Solution ◽  
Cement Composites ◽  
Porous Structures ◽  
Chemical Analyses ◽  
Inorganic Acid ◽  
Self Compacting Concrete ◽  
Physical Chemical

This article analyses the effect of crystallization additives on the long-term durability of self-compacting concretes (SCCs) in relation to specific types of chemically aggressive environments. The effect of both an inorganic acid solution and the aggressive solutions produced during plant ensilage were tested, while the effect of diesel on these modified concretes was also investigated. Attention was given to the effect of crystallization additives on the characteristically capillary porous structures of self-compacting concrete, specifically in terms of the long-term durability of SCCs in relation to the above-stated chemically aggressive solutions. The effect of aggressive environments was evaluated through a set of physical-mechanical trials and physical-chemical analyses.

The Evaluation of the Effect of Crystallization Additives on Long Term Durability of Cement Composites

2018 ◽  
Vol 276 ◽  
pp. 265-270
Author(s):  
Ámos Dufka ◽  
Tomáš Melichar
Keyword(s):  
Pore Structure ◽  
Cement Composites ◽  
Self Compacting Concrete ◽  
Aggressive Environment ◽  
Physico Chemical ◽  
Influence Of Crystallization ◽  
Long Life ◽  
Capillary Pore

The article deals with the influence of crystallization additives on the life of self-compacting concrete (so-called SCC concrete), which are exposed to chemically aggressive environments. The focus is not only on the effect of the crystallization additive on the characteristics of the capillary-pore structure of SCC concrete, but especially long life durability of self-compacting concrete (two years expozition). The effect of individual types of aggressive environment is assessed on the basis of a set of physico-mechanical and physico-chemical analyzes.

scholarly journals The influence of non-normative fuel on its operational properties

2019 ◽  
Vol 178 (3) ◽  
pp. 67-70
Author(s):  
Anna MATUSZEWSKA ◽  
Marlena OWCZUK
Keyword(s):  
Quality Standards ◽  
Chemical Analyses ◽  
Oxidation Processes ◽  
Long Term Storage ◽  
Physico Chemical ◽  
Resistance To Oxidation ◽  
Normative Requirements ◽  
Term Storage

Fuels that do not meet the requirements of quality standards cannot be used to power vehicle engines. The work involved physico-chemical analyses of non-normative fuel and its effect on the operational properties of the powered vehicle. The research fuels were two gasolines, characterized by a reduced resistance to oxidation processes due to their long-term storage. The results were compared to the properties of conventional fuels that met all normative requirements. The studies have shown that the fuel slightly deviating from the standard parameters does not noticeably affect the useful properties of the vehicle.

scholarly journals Comprehensive analysis and insights gained from long-term experience of the Spanish DILI registry

2021 ◽  
Author(s):  
Camilla Stephens ◽  
Mercedes Robles-Diaz ◽  
Inmaculada Medina-Caliz ◽  
Miren Garcia-Cortes ◽  
Aida Ortega-Alonso ◽  
...  
Keyword(s):  
Comprehensive Analysis ◽  
Long Term Experience

scholarly journals A Novel Highly Durable Carbon/Silver/Silver Chloride Composite Electrode for High-Definition Transcranial Direct Current Stimulation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1962
Author(s):  
Lingjun Li ◽  
Guangli Li ◽  
Yuliang Cao ◽  
Yvonne Yanwen Duan
Keyword(s):  
Service Life ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Silver Chloride ◽  
Cycling Performance ◽  
High Definition ◽  
Silver Silver ◽  
Sintered Ag ◽  
Silver Silver Chloride

High-definition transcranial direct current stimulation (HD-tDCS) is a promising non-invasive neuromodulation technique, which has been widely used in the clinical intervention and treatment of neurological or psychiatric disorders. Sintered Ag/AgCl electrode has become a preferred candidate for HD-tDCS, but its service life is very short, especially for long-term anodal stimulation. To address this issue, a novel highly durable conductive carbon/silver/silver chloride composite (C/Ag/AgCl) electrode was fabricated by a facile cold rolling method. The important parameters were systematically optimized, including the conductive enhancer, the particle size of Ag powder, the C:Ag:PTFE ratio, the saline concentration, and the active substance loading. The CNT/Ag/AgCl-721 electrode demonstrated excellent specific capacity and cycling performance. Both constant current anodal polarization and simulated tDCS measurement demonstrated that the service life of the CNT/Ag/AgCl-721 electrodes was 15-16 times of that of sintered Ag/AgCl electrodes. The much longer service life can be attributed to the formation of the three-dimensional interpenetrating conductive network with CNT doping, which can maintain a good conductivity and cycling performance even if excessive non-conductive AgCl is accumulated on the surface during long-term anodal stimulation. Considering their low cost, long service life, and good skin tolerance, the proposed CNT/Ag/AgCl electrodes have shown promising application prospects in HD-tDCS, especially for daily life scenarios.

scholarly journals Changes in surface characteristics and adsorption properties of 2,4,6-trichlorophenol following Fenton-like aging of biochar

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liqiang Cui ◽  
Qinya Fan ◽  
Jianxiong Sun ◽  
Guixiang Quan ◽  
Jinlong Yan ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Surface Properties ◽  
Aging Process ◽  
Surface Characteristics ◽  
Natural Soil ◽  
Peanut Shell ◽  
Soil Environment ◽  
Polluted Soils ◽  
Physico Chemical

AbstractFenton-like system formed in a natural soil environment deemed to be significant in the aging process of biochar. Aged biochars have distinct physico-chemical and surface properties compared to non-aged biochar. The aged biochar proved to be useful soil amendment due to its improved elements contents and surface properties. The biochar aging process resulted in increased surface area and pore volume, as well as carbon and oxygen-containing functional groups (such as C=O, –COOH, O–C=O etc.) on its surface, which were also associated with the adsorption behavior of 2,4,6-trichlorophenol (2,4,6-TCP). The biochar aging increased the adsorption capacity of 2,4,6-TCP, which was maximum at pH 3.0. The 2,4,6-TCP adsorption capacity of aged-bush biochar (ABB) and aged-peanut shell biochar (APB) was increased by 1.0–11.0% and 7.4–38.8%, respectively compared with bush biochar (BB) and peanut shell biochar (PB) at the same initial concentration of 2,4,6-TCP. All biochars had similar 2,4,6-TCP desorption rates ranging from 33.2 to 73.3% at different sorption temperatures and times. The desorbed components were mainly 2,4,6-TCP and other degraded components, which were low in concentration with small molecule substance. The results indicated that the aged-biochar could be effective for the long-term remediation of naturally organic polluted soils.

Comprehensive Analysis of Long-Term Outcomes after HeartMate 3 LVAD Implantation Depending on Surgical Access

2021 ◽  
Vol 40 (4) ◽  
pp. S180-S181
Author(s):  
R. Antończyk ◽  
A. Biełka ◽  
M. Kalinowski ◽  
J. Waszak ◽  
J. Małyszek-Tumidajewicz ◽  
...  
Keyword(s):  
Comprehensive Analysis ◽  
Long Term Outcomes ◽  
Surgical Access
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