Determination of the selectivity coefficient of a chloride ion selective electrode in alkaline media simulating the cement paste pore solution.

The measurement of the free chloride concentration in the pore solution of cement paste or concrete is of interest for assessing the probability of corrosion of the steel reinforcements embedded in concrete. This determination is performed through leaching or pore-pressing methods or through embedded potentiometric sensors into the hardened cementitious material. The potentiometric determination of chloride in cement paste pore solutions is limited by hydroxide ion interference, due to the high alkalinity of such media. The potentiometric selectivity coefficients, kCl-,OH-, are determined for a chloride ionic selective electrode in alkaline solutions simulating the electrolyte present within the pore network of cement paste and concrete. This is done using a fixed interference methodology, with least-squares non-linear curve fitting for obtaining the selectivity coefficients together with other relevant electrode parameters. The limit of detection of the Cl− ISE, due to OH− interference, varies with pH. For the pore solution corresponding to an ordinary Portland cement paste or concrete, this limit can be set between 3 × 10–3 m, and 7 × 10–3 m, i.e., approximately below a chloride concentration value of 1 × 10–2 molal. Taking into account these limits of detection the free Cl− concentrations able to depassivate the steel, can be adequately determined by potentiometric measurements with calibrated ISEs in the expressed pore solutions of Portland cement concretes, without significant influence of OH− interference. Nevertheless, this effect can prevent the adequate measurement of low free Cl− concentrations, below the corresponding limit of detection valu

Effects of red mud addition in the microstructure, durability and mechanical performance of cement mortars

Recently, there has been a great effort to incorporate industrial waste into cement-based materials to reach a more sustainable cement industry. In this regard, the Bayer process of obtaining alumina from bauxite generates huge amounts of waste called red mud. Few research articles have pointed out the possibility that red mud has pozzolanic activity. In view of that, the objective of this research is to analyse the short-term effects in the pore structure, mechanical performance and durability of mortars which incorporate up to 20% of red mud as a clinker replacement. As a reference, ordinary Portland cement and fly ash Portland cement mortars were also studied. The microstructure was characterised through mercury intrusion porosimetry and non-destructive impedance spectroscopy, which has not previously been used for studying the pore network evolution of red mud cement-based materials. The possible pozzolanic activity of red mud has been checked using differential scanning calorimetry. The non-steady state chloride migration coefficient and the mechanical properties were studied too. According to the results obtained, the addition of red mud entailed a greater microstructure refinement of the mortar, did not worsen the resistance against chloride ingress and reduced the compressive strength compared to control binders.Agencia Estatal de Investigación | Ref. BIA2016-80982-

A Galvanic Sensor for Monitoring the Corrosion Condition of the Concrete Reinforcing Steel: Relationship Between the Galvanic and the Corrosion Currents

This work reports a study carried out on the design and performance of galvanic and polarization resistance sensors to be embedded in concrete systems for permanent monitoring of the corrosion condition of reinforcing steel, aiming to establish a correlation between the galvanic currents, Igal, and the corrosion currents, Icorr, estimated from the polarization resistance, Rp. Sensors have been tested in saturated Ca(OH)2 aqueous solutions, under a variety of conditions, simulating the most important parameters that can accelerate the corrosion of concrete reinforcing steel, such as carbonation, ingress of chloride ions, presence or absence of O2. For all the conditions, the influence of temperature (20 to 55 °C) has also been considered. From this study, it could be concluded that the galvanic currents are sensitive to the various parameters following a trend similar to that of the Rp values. A relationship between the galvanic and the corrosion current densities was obtained and the limiting values of the Igal, indicative of the state condition of the reinforcing steel for the designed sensor, were established

Neoadjuvant Chemotherapy plus Interval Cytoreductive Surgery with or without Hyperthermic Intraperitoneal Chemotherapy (NIHIPEC) in the Treatment of Advanced Ovarian Cancer: A Multicentric Propensity Score Study

Simple Summary Advanced ovarian cancer (Stages III-IV) continues to be one of the gynecological tumors with the highest mortality. Standard treatment consists of debulking surgery and subsequent adjuvant chemotherapy. Recently, some authors have postulated that the administration of hyperthermic chemotherapy during surgery could increase the survival of patients, especially in cases in which chemotherapy had already been administered before surgery to reduce tumor volume. Our study is important because it collects data from 11 tertiary hospitals in Spain, and the data are subjected to a statistical technique that reproduces the data that we would find in a prospective study but using retrospective data (propensity score matching). It also offers a current view of the status of ovarian cancer treatment in our country.Abstract Introduction: Epithelial ovarian cancer (EOC) is primarily confined to the peritoneal cavity. When primary complete surgery is not possible, neoadjuvant chemotherapy (NACT) is provided; however, the peritoneum-plasma barrier hinders the drug effect. The intraperitoneal administration of chemotherapy could eliminate residual microscopic peritoneal tumor cells and increase this effect by hyperthermia. Intraperitoneal hyperthermic chemotherapy (HIPEC) after interval cytoreductive surgery could improve outcomes in terms of disease-free survival (DFS) and overall survival (OS). Materials and Methods: A multicenter, retrospective observational study of advanced EOC patients who underwent interval cytoreductive surgery alone (CRSnoH) or interval cytoreductive surgery plus HIPEC (CRSH) was carried out in Spain between 07/2012 and 12/2021. A total of 515 patients were selected. Progression-free survival (PFS) and OS analyses were performed. The series of patients who underwent CRSH or CRSnoH was balanced regarding the risk factors using a statistical analysis technique called propensity score matching. Results: A total of 170 patients were included in each subgroup. The complete surgery rate was similar in both groups (79.4% vs. 84.7%). The median PFS times were 16 and 13 months in the CRSH and CRSnoH groups, respectively (Hazard ratio (HR) 0.74; 95% CI, 0.58-0.94; p = 0.031). The median OS times were 56 and 50 months in the CRSH and CRSnoH groups, respectively (HR, 0.88; 95% CI, 0.64-1.20; p = 0.44). There was no increase in complications in the CRSH group. Conclusion: The addition of HIPEC after interval cytoreductive surgery is safe and increases DFS in advanced EOC patients

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

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Population distribution of invasive specie Ailanthus altissima (mill.) Swingle in the Carrascal de la Font Roja Natural Park

La Estación Científica Font Roja Natura-UA ha iniciado un estudio sobre la presencia de la especie invasora Ailanthus altissima (Mill.) Swingle en el Parque Natural del Carrascal de la Font Roja. Las invasiones biológicas se han convertido en un grave problema ecológico y económico, sobre todo en un parque natural. Tanto el PORN como el PRUG del Parque regulan este aspecto proponiendo la eliminación de las invasoras en el área de influencia y dentro del Parque. Se ha constatado que la especie está presente en la Font Roja sobre todo en las zonas perturbadas o degradadas y en barrancos y cursos de agua temporales y/o continuos. Y lo que es más importante, está en clara expansión.L’Estació Científica Font Roja Natura-UA ha iniciat un estudi sobre la presència de l’espècie invasora Ailanthus altissima (Mill.) Swingle en el Parc Natural del Carrascal de la Font Roja. Les invasions biològiques s’han convertit en un greu problema ecològic i econòmic, i més en un parc natural. Tant el PORN com el PRUG del Parc regulen aquest aspecte proposant l’eliminació de les invasores en l’àrea d’influència i dins el Parc. S’ha constatat que l’espècie és present a la Font Roja sobre tot a les zones pertorbades o degradades i en barrancs i cursos d’aigua temporals i/o continus. I el que és més important, està en clara expansió.The Scientific Station Font Roja Natura-UA has begun a survey on the presence of the invader species Ailanthus altissima (Mill.) Swingle in en el Natural Park of Font Roja Carrascal. Biological invasions have become a major economic and ecological problem, especially in a natural park. Both PORN and PRUG regulate this proposing the removal of invader in the influence area and inside the boundaries of the Park. It has been proved that the species is present in the disturbed and degradated areas in Font Roja and in gorges and temporary or continuous brooklets. And the most worrying fact is the invader is in full expansion.Consellería de medio Ambiete, Agua, Urbanismo y Vivienda, Generalitat Valenciana. Gerència de Medi Ambiet, Ajuntament d'Alcoi. Caja del Mediterráneo

Actitud emprendedora entre el estudiantado

Esta investigación plantea estudiar la actitud emprendedora y el interés por el emprendimiento entre el estudiantado de la Universidad de Alicante, ya que puede ser importante como instrumento para luchar contra la posible crisis que se avecina. El sistema económico alicantino está afectado a causa de la crisis originada por el COVID- 19 y posteriormente, por la guerra de Ucrania. En este contexto, el conjunto de los estudiantes universitarios puede ser importantes para planifica estrategias que fortalezca en tejido empresarial. El objetivo de esta investigación es identificar actitudes emprendedoras entre el estudiantado universitario, considerando planteamientos teóricos en base a la relación entre las variables de estudio. Para ello, se utilizó un diseño metodológico de tipo descriptivo, que analizaba las contestaciones de una encuesta realizada con el propósito de analizar la percepción de los estudiantes respecto a sus actitudes y a su interés por el emprendimiento. En general, el estudiantado de la Universidad de Alicante considera que tiene las cualidades y actitudes para emprender y además, manifiestan tener una alta predisposición para hacerlo

Educación de la capacidad creativa

La finalidad de este taller no es únicamente mostrar los conocimientos adquiridos sobre: El Arte Abstracto; sino, aplicar métodos y técnicas de trabajo a través de contenidos diversos, reflejados en los temas transversales: - Respetar las culturas diferentes a la nuestra. - Concienciar del cuidado del Medio Ambient

Comparison between dcrit considering the abrupt variation and inflexion in the concrete mercury intrusion porosimetry curve

Mercury intrusion porosimetry (MIP) has been widely used to evaluate the quality of concrete through the pore size distribution parameters. Two of these parameters are the critical pore diameter (Dcrit) and the percentage of the most interconnected net of pores compared to the total volume of pores. Some\ud researchers consider Dcrit as the diameter obtained from the inflexion point of the cumulative mercury intrusion curve while others consider Dcrit as the diameter obtained from the point of abrupt variation in the same curve. This study aims to analyze two groups of concretes of varying w/c ratios, one cast with pozzolanic cement and another with high initial strength cement, in order to determine which of these diameters feature a better correlation with the quality parameters of the concretes. The concrete quality parameters used for the evaluations were (1) the w/c ratios and (2) chloride diffusion coefficients measured at approximately 90 days. MIP cumulative distributions of the same concretes were also measured at about 90 days, and Dcrit values were determined (1) from the point of abrupt variation and alternatively, (2) from the inflexion point of each of these plots. It was found that Dcrit values measured from the point of abrupt variation were useful indicators of the quality of the concrete, but the Dcrit values based on the inflexion points were not. Hence, it is recommended that Dcrit and the percentage of the most interconnected volume of pores should be obtained considering the point of abrupt variation of the cumulative curve of pore size distribution