Comparación entre el comportamiento mecánico a tracción, fractura y fatiga de armaduras de refuerzo fabricadas con distintos tipos de acero

The use of austenitic stainless steels as rebar is an option increasingly used in reinforced concrete structures exposed to aggressive environments and especially those that have to work in marine environments. The same is true for duplex stainless steel rebars, although nowadays they have a lower use, mainly due to the fact that their inclusion in the reinforced concrete standards was delayed 10 years compared to austenitic stainless steel ones, and consequently their in-service behavior is not as well known. A study of the mechanical properties, including fracture toughness, fatigue behaviour and corrosion resistance in saline alkaline environments of austenitic (AISI 304LN and 316LN) and duplex (D2205) stainless steel reinforcing bars was performed in this work. Bars made on a high ductility carbon steel (B500SD) that are normally used to reinforce concrete were also characterized and used as a comparison. Stainless steel reinforcing bars show mechanical properties at least similar but usually higher than one of the best carbon steel re-bars (B500SD), along with a significantly higher ductility and, of course, much better corrosion behaviour in saline alkaline environments.El uso de aceros inoxidables austeníticos como armaduras de refuerzo es una opción cada vez más utilizada en estructuras de hormigón armado expuestas a ambientes agresivos y especialmente en las que han de trabajar en ambientes marinos. Lo mismo cabe decir de las armaduras de acero inoxidable dúplex, si bien su uso es menor, debido sobre todo a que su inclusión en la normativa aplicable al armado de hormigón se retrasó 10 años con respecto a los inoxidables austeníticos y, consecuentemente, su comportamiento en servicio es menos conocido. En este trabajo se analiza el comportamiento mecánico, incluyendo fractura y fatiga, así como la resistencia a la corrosión en medios que simulan un hormigón contaminado de cloruros, de armaduras fabricadas tanto con aceros inoxidables austeníticos (304LN y 316LN) como dúplex (D2205). Asimismo se han caracterizado armaduras convencionales de acero al carbono (B500SD) como comparación. Las armaduras de acero inoxidable muestran unas propiedades mecánicas similares e incluso superiores a las de acero al carbono, exhibiendo además una ductilidad y una resistencia a la corrosión en un medio alcalino salino claramente ventajosas

An active tectonic field for CO2 storage management: the Hontomín onshore case study (Spain)

One of the concerns of underground CO2 onshore storage is the triggering of induced seismicity and fault reactivation by the pore pressure increasing. Hence, a comprehensive analysis of the tectonic parameters involved in the storage rock formation is mandatory for safety management operations. Unquestionably, active faults and seal faults depicting the storage bulk are relevant parameters to be considered. However, there is a lack of analysis of the active tectonic strain field affecting these faults during the CO2 storage monitoring. The advantage of reconstructing the tectonic field is the possibility to determine the strain trajectories and describing the fault patterns affecting the reservoir rock. In this work, we adapt a methodology of systematic geostructural analysis to underground CO2 storage, based on the calculation of the strain field from kinematics indicators on the fault planes (ey and ex for the maximum and minimum horizontal shortening, respectively). This methodology is based on a statistical analysis of individual strain tensor solutions obtained from fresh outcrops from the Triassic to the Miocene. Consequently, we have collected 447 fault data in 32 field stations located within a 20 km radius. The understanding of the fault sets’ role for underground fluid circulation can also be established, helping further analysis of CO2 leakage and seepage. We have applied this methodology to Hontomín onshore CO2 storage facilities (central Spain). The geology of the area and the number of high-quality outcrops made this site a good candidate for studying the strain field from kinematics fault analysis. The results indicate a strike-slip tectonic regime with maximum horizontal shortening with a 160 and 50◦ E trend for the local regime, which activates NE–SW strike-slip faults. A regional extensional tectonic field was also recognized with a N–S trend, which activates N–S extensional faults, and NNE–SSW and NNW– SSE strike-slip faults, measured in the Cretaceous limestone on top of the Hontomín facilities. Monitoring these faults within the reservoir is suggested in addition to the possibility of obtaining a focal mechanism solutions for microearthquakes (M < 3)This work has been partially supported by the European Project ENOS: ENabling Onshore CO2 Storage in Europe, H2020 Project ID: 653718 and the Spanish project 3GEO, CGL2017-83931-C3-2-P, MICIU-FEDE

Neutrophil to lymphocyte ratio in oropharyngeal squamous cell Carcinoma: A systematic review and meta-analysis

Neutrophil-to-lymphocyte ratio (NLR) has been associated with survival in various cancers, including head and neck cancer. However, there is limited information on its role in oropharyngeal squamous cell carcinomas (OPSCC) according to HPV status. This prompted the present metaanalysis. Studies were selected when the prognostic value of NLR prior to treatment was evaluated in OPSCC patients, the cutoff value of NLR was available, and the prognostic value of NLR was evaluated by time-to-event survival analysis. A total of 14 out of 492 articles, including 7647 patients, were analyzed. The results showed a worse prognosis for the patients with a high NLR: The combined hazard ratios (HR) for overall survival (OS) in patients with an elevated NLR was 1.56 (95% confidence interval (CI) 1.21–2.02; p = 0.0006), for disease-free survival was 1.52 (95% CI 1.34–1.73; p < 0.00001), and for recurrence-free survival was 1.86 (95% CI 1.50–2.30; p < 0.00001). This worse prognosis ofhigh NLR was exclusive of HPV-positive patients: HR for OS in the HPV-positive subgroup was 4.05 (95% CI 1.90–8.62 (p = 0.0003), and in the HPV-negative subgroup 0.92 (95% CI 0.47–1.80; p = 0.82). The prognosis of NLR was not influenced by treatment: The HR for OS for patients treated with radiotherapy/chemoradiotherapy (RT/CRT) was 1.48 (95% CI 1.09–2.01; p = 0.01), and for patients treated with surgery (±RT/CRT) was 1.72 (95% CI 1.08–2.72; p = 0.02). In conclusion, an elevated NLR relates to worse outcomes in patients with HPV-positive OPSCC.info:eu-repo/semantics/publishedVersio

Fatigue crack propagation prediction of a pressure vessel mild steel based on a strain energy density model

Fatigue crack growth (FCG) rates have traditionally been formulated from fracture mechanics, whereas fatigue crack initiation has been empirically described using stress-life or strain-life methods. More recently, there has been efforts towards the use of the local stress-strain and similitude concepts to formulate fatigue crack growth rates. A new model has been developed which derives stress-life, strain-life and fatigue crack growth rates from strain energy density concepts. This new model has the advantage to predict an intrinsic stress ratio effect of the form ?ar=(?amp)?·(?max )(1-?), which is dependent on the cyclic stress-strain behaviour of the material. This new fatigue crack propagation model was proposed by Huffman based on Walkerlike strain-life relation. This model is applied to FCG data available for the P355NL1 pressure vessel steel. A comparison of the experimental results and the Huffman crack propagation model is made

Neutrophil to Lymphocyte Ratio in Oropharyngeal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Neutrophil-to-lymphocyte ratio (NLR) has been associated with survival in various cancers, including head and neck cancer. However, there is limited information on its role in oropharyngeal squamous cell carcinomas (OPSCC) according to HPV status. This prompted the present meta-analysis. Studies were selected when the prognostic value of NLR prior to treatment was evaluated in OPSCC patients, the cutoff value of NLR was available, and the prognostic value of NLR was evaluated by time-to-event survival analysis. A total of 14 out of 492 articles, including 7647 patients, were analyzed. The results showed a worse prognosis for the patients with a high NLR: The combined hazard ratios (HR) for overall survival (OS) in patients with an elevated NLR was 1.56 (95% confidence interval (CI) 1.21–2.02; p = 0.0006), for disease-free survival was 1.52 (95% CI 1.34–1.73; p < 0.00001), and for recurrence-free survival was 1.86 (95% CI 1.50–2.30; p < 0.00001). This worse prognosis of high NLR was exclusive of HPV-positive patients: HR for OS in the HPV-positive subgroup was 4.05 (95% CI 1.90–8.62 (p = 0.0003), and in the HPV-negative subgroup 0.92 (95% CI 0.47–1.80; p = 0.82). The prognosis of NLR was not influenced by treatment: The HR for OS for patients treated with radiotherapy/chemoradiotherapy (RT/CRT) was 1.48 (95% CI 1.09–2.01; p = 0.01), and for patients treated with surgery (±RT/CRT) was 1.72 (95% CI 1.08–2.72; p = 0.02). In conclusion, an elevated NLR relates to worse outcomes in patients with HPV-positive OPSCC