Resistance to fatigue of self-healed concrete based on encapsulated polymer precursors

Moving cracks are often present in concrete structures and in those circumstances any self-healing technique for concrete must satisfy specific performance requirements, to guarantee its increased durability. These requirements include the capability of withstanding multiple cycles of crack movement without failing to keep healed cracks sealed. This paper shows early results from a testing protocol suggested by the authors to assess the performance of polymers as healing materials for moving cracks. Ultrasound (US) shear waves were used for continuous monitoring of small prismatic mortar specimens containing a single healed crack under a cyclic load. The maximum amplitude of US waves transmitted across healed cracks was correlated to the area effectively healed and the magnitude of crack movement. A decreasing trend of the maximum amplitude during cyclic loading was observed for strain levels on the polymer corresponding to 70% of its strain limit, but soundness at lower strain levels was confirmed after 300 cycles

Local Anesthetics Infiltration and Wound Healing Process

It is a good practice, nowadays, to infiltrate local anesthetics along the incision to prevent postoperative pain. This can reduce the use of opioids and the side effects they cause. It is known clearly that the surgical trauma causes inflammatory reaction, and this can be the beginning of a bad cicatrization or even a scar. The use of local anesthetics preventing the acute pain is a very simple technique and has proved to be useful. Nevertheless, the reaction that various anesthetics have over the tissues and the cicatrization process is yet controversial and deserves to be investigated deeply. The use of different formulations of these drugs has been stimulated. The duration and secureness have been the goals of many researches. Levobupivacaine, ropivacaine, and bupivacaine for their long action; lidocaine for less toxicity; and liposomal formulation for the longest duration ever seen, all of them have been indicated in the postoperative pain management. The aim of this chapter is to evaluate the role of long duration local anesthetics on the inflammatory reaction and consequently the collagen production and resistance of the tissue to traction

Moving towards a realistic implementation of self-healing concrete based on encapsulated polymer precursors

Extensive research has already been performed on self-healing concrete based on a triggered release of liquid polymer precursors from a carrier, especially during the past decade. However, tests on large concrete specimens are still seldom performed and the self-healing techniques used are often not practical or effective if implemented at a large scale. This paper presents an analysis of the most relevant properties for carriers that are critical for moving the technology closer to a realistic implementation. The study contemplates the assessment of the dimensions of tubular glass capsules that result in a high survival rate if directly added to concrete during mixing, while still being able to rupture during realistic crack formation in the host concrete matrix. Finally, a trial implementation of randomly dispersed glass tubular carriers in concrete beams is presented. This system is composed of a typical OPC concrete with tubular glass capsules added during the mixing process. It is shown that this system works and the crack planes cross several capsules that subsequently release the polymer precursor into the crack. However, the dosage used needs to be increased if a satisfying healed area is to be achieved

Applying computational fluid dynamics in the development of smart ripening rooms for traditional cheeses

Traditional ewe's cheese producers face certain challenges caused by fluctuating environmental parameters inside the ripening room, which lead to lack of homogeneity in the final product. The present research discusses the application of computer fluid dynamics for simulating the distribution of environmental parameters, predicting the airflow pattern, and identifying critical areas where such parameters could cause reduced cheese quality. A new monitoring system was developed including presence sensors, temperature and humidity dataloggers, pneumatic actuators, microcontrollers, and microcomputers connected remotely for control, data visualization, and processing. The validation of the computer simulation and monitoring system was made with a batch of 40 ewe's cheeses distributed in three different zones inside a prototype ripening room and ripened for 35 days. At 35 days, a physical, chemical, and microbiological characterization of cheeses was made for evaluation of the influence of environmental conditions on cheese quality. The comparison between simulated and local measurements showed close agreement, especially concerning air velocity inside the stacks of cheese. The results of Pearson's correlation analysis and PCA concluded that temperature affected the appearance of the rind, hardness, number and area occupied by holes. Humidity affected aw and mFeret. Air velocity affected pH and the circularity of gas holes

Best practice guide: Solutions for mitigating the impacts of roads on animal communities

This guide presents a set of interventions that were implemented and tested in the framework of the LIFE LINES project (LIFE14 NAT/PT/001081), coordinated by Universidade of Évora, in close partnership with authorities responsible for the management and maintenance of road infrastructures: IP – Infraestruturas de Portugal S.A., and the municipalities of Évora and Montemor-o-Novo. Due to the nature of the project and of its geographic framework, these actions are based on demonstrative and innovating solutions at the national level, primarily targeting animal communities, and whose effectiveness is evaluated in terms of success and cost of implementation and maintenance, aiming at their replication in future infrastructure contracts and other geographic contexts and species. This guide is meant to convey the implemented solutions, namely their characteristics, technical requirements, and cost-benefit evaluations, supporting the analysis of alternative solutions to prevent impacts on animal communities when planning new roads, requalifying existing road infrastructures, or mitigating localized roadkill. Concomitantly, this guide also aims at promoting road safety by reducing the risk of collisions with medium- to large-size animals. This information is directed to those who must evaluate environmental impacts (environmental agencies and nature conservation institutes), authorities in charge of road management (concession holders, municipalities), as well as project-designers, environmental consultants, road building and maintenance companies, and other agents concerned with the implementation of good environmental practices. This guide is applicable to the areas of land use planning, infrastructure’s project or management, and environmental sciences.LIFE-LINES (LIFE14 NAT / PT / 001081) Linear Infrastructure Networks with Ecological Solutions 60% co-financed project by the LIFE - Nature and Biodiversity Program of the European Commissio

Mineral stress affects the cell wall composition of grapevine (Vitis vinifera L.) callus

Versão provisória aceite p. publicação na Plant Science (ISSN 0168-9452)em 19-01-2013Grapevine (Vitis vinifera L.) is one of the most economically important fruit crops in the world. Deficit in nitrogen, phosphorus and sulfur nutrition impairs essential metabolic pathways. The influence of mineral stress in the composition of the plant cell wall (CW) has received residual attention. Using grapevine callus as a model system, 6-weeks deficiency of those elements caused a significant decrease in growth. Callus CWs were analyzed by Fourier transform infrared spectroscopy (FT-IR), by quantification of CW components and by immunolocalization of CW epitopes with monoclonal antibodies. PCA analysis of FT-IR data suggested changes in the main components of the CW in response to individual mineral stress. Decreased cellulose, modifications in pectin methyl esterification and increase of structural proteins were among the events disclosed by FT-IR analysis. Chemical analyses supported some of the assumptions and further disclosed an increase in lignin content under nitrogen deficiency, suggesting a compensation of cellulose by lignin. Moreover, polysaccharides of callus under mineral deficiency showed to be more tightly bonded to the CW, probably due to a more extensive cross-linking of the cellulose-hemicellulose network. Our work showed that mineral stress impacts the CW at different extents according to the withdrawn mineral element, and that the modifications in a given CW component are compensated by the synthesis and/or alternative linking between polymers. The overall results here described for the first time pinpoint the CW of Vitis callus different strategies to overcome mineral stress, depending on how essential they are to cell growth and plant development

Simulation-aided design of tubular polymeric capsules for self-healing concrete

Polymeric capsules can have an advantage over glass capsules used up to now as proof-of-concept carriers in self-healing concrete. They allow easier processing and afford the possibility to fine tune their mechanical properties. Out of the multiple requirements for capsules used in this context, the capability of rupturing when crossed by a crack in concrete of a typical size is one of the most relevant, as without it no healing agent is released into the crack. This study assessed the fitness of five types of polymeric capsules to fulfill this requirement by using a numerical model to screen the best performing ones and verifying their fitness with experimental methods. Capsules made of a specific type of poly(methyl methacrylate) (PMMA) were considered fit for the intended application, rupturing at average crack sizes of 69 and 128 μm, respectively for a wall thickness of ~0.3 and ~0.7 mm. Thicker walls were considered unfit, as they ruptured for crack sizes much higher than 100 μm. Other types of PMMA used and polylactic acid were equally unfit for the same reason. There was overall good fitting between model output and experimental results and an elongation at break of 1.5% is recommended regarding polymers for this application