Damage Detection in FRP-Reinforced Concrete Elements.

Fiber-Reinforced Polymer (FRP) composites have emerged as a promising alternative to conventional steel reinforcements in concrete structures owing to their benefits of corrosion resistance, higher strength-to-weight ratio, reduced maintenance cost, extended service life, and superior durability. However, there has been limited research on non-destructive testing (NDT) methods applicable for identifying damage in FRP-reinforced concrete (FRP-RC) elements. This knowledge gap has often limited its application in the construction industry. Engineers and owners often lack confidence in utilizing this relatively new construction material due to the challenge of assessing its condition. Thus, the main objective of this study is to determine the applicability of two of the most common NDT methods: the Ground-Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU) methods for the detection of damage in FRP-RC elements. Three slab specimens with variations in FRP type (glass-, carbon- and basalt-FRP, i.e., GFRP, CFRP, and BFRP, respectively), bar diameter, bar depths, and defect types were investigated to determine the limitations and detection capabilities of these two NDT methods. The results show that GPR could detect damage in GFRP bars and CFRP strands, but PAU was limited to damage detection in CFRP strands. The findings of this study show the applicability of conventional NDT methods to FRP-RC and at the same time identify the areas with a need for further research.

FRP-Reinforced/Strengthened Concrete: State-of-the-Art Review on Durability and Mechanical Effects.

Fiber-reinforced polymer (FRP) composites have gained increasing recognition and application in the field of civil engineering in recent decades due to their notable mechanical properties and chemical resistance. However, FRP composites may also be affected by harsh environmental conditions (e.g., water, alkaline solutions, saline solutions, elevated temperature) and exhibit mechanical phenomena (e.g., creep rupture, fatigue, shrinkage) that could affect the performance of the FRP reinforced/strengthened concrete (FRP-RSC) elements. This paper presents the current state-of-the-art on the key environmental and mechanical conditions affecting the durability and mechanical properties of the main FRP composites used in reinforced concrete (RC) structures (i.e., Glass/vinyl-ester FRP bars and Carbon/epoxy FRP fabrics for internal and external application, respectively). The most likely sources and their effects on the physical/mechanical properties of FRP composites are highlighted herein. In general, no more than 20% tensile strength was reported in the literature for the different exposures without combined effects. Additionally, some provisions for the serviceability design of FRP-RSC elements (e.g., environmental factors, creep reduction factor) are examined and commented upon to understand the implications of the durability and mechanical properties. Furthermore, the differences in serviceability criteria for FRP and steel RC elements are highlighted. Through familiarity with their behavior and effects on enhancing the long-term performance of RSC elements, it is expected that the results of this study will help in the proper use of FRP materials for concrete structures.

Mastectomía radical con reconstrucción inmediata en el Instituto Autónomo Hospital Universitario de Los Andes, período junio 2012-abril 2015 / Radical mastectomy with reconstruction immediate Instituto Autónomo Hospital Universitario de Los Andes in the period June 2012-April 2015

Introducción: La reconstrucción mamaria es parte fundamental del tratamiento de la mujer mastectomizada por cáncer de mama. Tras comprobarse que la reconstrucción no influye negativamente sobre la enfermedad neoplásica, sino que es trascendental para la rehabilitación física y psicológica de la paciente, su desarrollo se ha visto favorecido. Materiales y métodos: Se realizó un estudio de tipo prospectivo, observacional, descriptivo y comparativo tipo ensayo clínico, entre los colgajos miocutáneos TRAM y dorsal ancho ampliado, en las pacientes sometidas a cirugía electiva. Resultados: Se incluyó un total de 36 pacientes, dividiéndose en 2 grupos de 20 pacientes para el grupo TRAM y 16 para el grupo de dorsal ampliado, con una edad promedio de 45,45 ± 9,50 años en el TRAM y de 56,09 ± 9,07 años en el de dorsal ampliado, con un IMC que oscilaba en ambos grupos entre 25,0-29,9. Se realizó en 19 pacientes mastectomía radical modificada tipo Madden + TRAM, representando un 80%, donde se simetrizó el 15% de dicho grupo. Se realizó un Halsted + TRAM bipediculado, representando un 5%; al grupo dorsal se les realizó mastectomía radical modificada tipo Madden, simetrizándose el 31,3%. Respecto a las complicaciones, se observó en general que en las pacientes del grupo TRAM predominaron la infección de la herida operatoria y la necrosis, con un 25,0% cada una, seguidas de seroma y dehiscencia de sutura con un 10% cada una, describiéndose solo un caso de eventración, totalizando 11 pacientes, donde 3 presentaron 2 o más complicaciones de las descritas anteriormente asociadas; en el grupo de dorsal ampliado predominaron los seromas, con un 18,8%, y necrosis en un 12,5%, totalizando 4 pacientes, igualmente una con 2 complicaciones asociadas. Conclusiones: La reconstrucción mamaria posterior a la Mastectomía con sus diferentes técnicas representa un procedimiento seguro y que se debe implementar en todos los centros en que se manejen pacientes con cáncer de mama, como en nuestro servicio de Cirugía Oncológica.

Introduction: Breast reconstruction is a fundamental part of the treatment of women with mastectomies. After finding that rebuilding a negative effect on the neoplastic disease, but is critical to the physical and psychological rehabilitation of the patient, its development has been favored. Selecting the right process depends on multiple factors such as patient age, stage of disease, smoking, obesity, adjuvant treatment, experience and technical capacity of the center where they will perform the reconstruction, among other. Materials and methods: A study of prospective, observational, descriptive and comparative clinical trial type was held between myocutaneous flaps extended dorsal and TRAM, in patients undergoing elective surgery. Results: A total of 36 patients were included, divided into 2 groups of 20 patients TRAM group and 16 expanded dorsal group, with a mean age of 45.45 ± 9,50 years old in the TRAM and the expanded dorsal group of 56.09 ± 9.07 years old with a BMI in both groups ranged between 25.0-29.9. They were performed in 19 patients radical modified mastectomy Madden + TRAM type representing 80%, where 15% of this group symmetrize. A Halsted + TRAM bipedicled was performed representing 5%; the dorsal group underwent modified radical mastectomy Madden 100%, symmetrize the 31.3%. Overall complications was observed in patients TRAM group predominated operative wound infection and necrosis with 25.0% each, followed by seroma and wound dehiscence with 10% each, describing only one hernia totaling 11 patients, where 3 patients had 2 or more complications associated previously described; in extended dorsal group seroma they predominated with 18.8% and 12.5% necrosis, totaling 4 patients alike with 2 associated complications. Conclusions: The post-mastectomy breast reconstruction with different techniques is a safe procedure that must be implemented in all centers where patients with breast cancer, and our service are handled Surgical Oncology.

Integrated study of metal behavior in Mediterranean stream ecosystems: a case-study.

The objective of the present work was to assess the ecosystem status of Francolí river (Catalonia, Spain), a Mediterranean stream basin with contrasting human influences. An integrated approach was designed by combining physicochemical, biological and ecotoxicological analyses. The content of metals (As, Cd, Cr, Co, Cu, Hg, Ni, Pb, and Zn) was analyzed in samples of water, benthic sediments and aquatic macroinvertebrates. In addition, the potentially bioavailable fraction of metals in water and sediments was determined by using diffusive gradient in thin-films (DGTs) and sequential extraction of sediments (BCR), respectively. The biological quality was evaluated through aquatic macroinvertebrate communities, while the ecotoxicological status was assessed by Microtox(®) with Vibrio fischeri. Finally, an analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) was performed to evaluate the sediment toxicity associated to metal content. According to the results, DGTs and BCR are suitable methodologies to predict the potential bioavailable fraction of metals in freshwater systems. Moreover, ecotoxicity evaluation by means of V. fischeri, in combination with the chemical characterization and the biological quality assessment, should be complementarily used to get a better diagnose of freshwater systems.

Point-source effects on N and P uptake in a forested and an agricultural Mediterranean streams.

We examined the effect of point-source inputs from wastewater treatment plants (WWTP) on in-stream uptake of ammonium, nitrate and phosphate and compared it between two streams draining catchments with contrasting land use. The selected streams were La Tordera and Gurri (NE Spain), draining a forest- and an agriculture-dominated catchment, respectively. In each stream, we compared nutrient uptake metrics, estimated from nutrient additions, between two reaches located upstream and downstream of a WWTP input. Measurements were done on 8-9 dates during 2002-2003. In La Tordera, the point-source increased concentrations of all studied nutrients; whereas in Gurri, this effect was less evident. Point-source effects on nutrient uptake differed between the two streams, and among solutes. In La Tordera, uptake lengths (S(w)) of ammonium and phosphate averaged hundreds of meters above the point-source, and increased (i.e., decreased uptake efficiency) 4 and 5 times, respectively, below the point-source. S(w) of nitrate was ≥2km regardless of reach location. In Gurri, S(w) of all studied nutrients was within the km range in the two reaches. In this stream, diffuse nutrient inputs from adjacent fields may overwhelm the local effect of the point-source input. Uptake velocities (v(f)) of the studied nutrients ranged between 10EXP(-6) and 10EXP(-4)m/s in the two streams, and were similar between the two reaches in each stream. However, phosphate v(f) decreased under increasing concentrations following a power function. This trend remained significant when combining our results with those compiled from literature, suggesting the efficiency loss response may be a general trend for phosphate across streams. The relative increases in uptake rates (U) below the point-source were proportional to the relative point-source contribution to downstream nutrient loads, especially for ammonium and nitrate. However, the increases in U were not enough to compensate for the increases in nutrient loads downstream of the WWTP input.