Seismic vulnerability analysis of wide-beam buildings in Spain

A number of short-to-mid height RC buildings with wide beams have been constructed in moderate-seismicity areas of Spain. The seismic behavior in the direction of the wide beams appears to be deficient because of low lateral strength, low ductility of the wide beams, big strut compressive forces inside the column-beam connections, and unreliable contribution of the spandrel zones of the wide beams. In the orthogonal direction, the behavior is worse since only the joists and the façade beams contribute to the lateral resistance. The objective is to assess the seismic capability of these structures; further research will involve proposing retrofit strategies. The research approach consists of selecting a number of representative buildings and evaluating their vulnerability by code-type, push-over and dynamic analyses. The cooperation of the masonry infill walls is accounted for. The main conclusion is that the seismic behavior of these buildings is inadequate in most of the situations

Vulnerability analysis of RC buildings with wide beams located in moderate seismicity regions

A significant number of short-to-mid height RC buildings with wide beams have been constructed in areas of moderate seismicity of Spain, mainly for housing and administrative use. The buildings have a framed structure with one-way slabs; the wide beams constitute the distinctive characteristic, their depth being equal to that of the rest of the slab, thus providing a flat lower surface, convenient for construction and the layout of facilities. Seismic behavior in the direction of the wide beams appears to be deficient because of: (i) low lateral strength, mainly because of the small effective depth of the beams, (ii) inherent low ductility of the wide beams, generated by high amount of reinforcement, (iii) the big strut compressive forces developed inside the column-beam connections due to the low height of the beams, and (iv) the fact that the wide beams are wider than the columns, meaning that the contribution of the outer zones to the resistance of the beam-column joints is unreliable because there is no torsion reinforcement. In the orthogonal direction, the behavior is worse since the only members of the slabs that contribute to the lateral resistance are the joists and the façade beams. Moreover, these buildings were designed with codes that did not include ductility requirements and required only a low lateral resistance; indeed, in many cases, seismic action was not considered at all. Consequently, the seismic capacity of these structures is not reliable. The objective of this research is to assess numerically this capability, whereas further research will aim to propose retrofit strategies. The research approach consists of: (i) selecting a number of 3-story and 6-story buildings that represent the vast majority of the existing ones and (ii) evaluating their vulnerability through three types of analyses, namely: code-type, push-over and nonlinear dynamic analysis. Given the low lateral resistance of the main frames, the cooperation of the masonry infill walls is accounted for; for each representative building, three wall densities are considered. The results of the analyses show that the buildings in question exhibit inadequate seismic behavior in most of the examined situations. In general, the relative performance is less deficient for Target Drift CP (Collapse Prevention) than for IO (Immediate Occupancy). Since these buildings are selected to be representative of the vast majority of buildings with wide beams that were constructed in Spain without accounting for any seismic consideration, our conclusions can be extrapolated to a broader scenario

Effect of disorder on the vortex-lattice melting transition

We use a three dimensional stacked triangular network of Josephson junctions as a model for the study of vortex structure in the mixed state of high Tc superconductors. We show that the addition of disorder destroys the first order melting transition occurring for clean samples. The melting transition splits in two different (continuous) transitions, ocurring at temperatures Ti and Tp (>Ti). At Ti the perpendicular-to-field superconductivity is lost, and at Tp the parallel-to-field superconductivity is lost. These results agree well with recent experiments in YBaCuO.Comment: 4 pages + 2 figure

Impact of the dicyanomethylene substitution position on the cyclophane macrocycle formation in carbazole-based biradicals

π-Conjugated biradical compounds, featuring unique unsaturated valences and radical centers in the ground state, are fundamentally important for understanding the nature of chemical bonds and have potential applications in material science. [1] Recently, it has been demonstrated that several -conjugated mono- and biradicals systems form long strain -bonds between two unpaired electrons resulting in macrocyclic or staircase oligomers or polymers by self-assembly processes. [2] Therefore, these materials are potential building blocks for dynamic covalent chemistry (DCC) since the aggregates can be formed or broken upon soft external stimuli. For instance, 2,7-dicyanomethylene-9-(2-ethylhexyl)carbazole biradical (p-Cz-alkyl in Figure 1) reversibly converts upon soft stimuli (temperature, pressure, light) to a cyclophane tetramer as a result from the formation (or bond cleavage) of long C-C single bonds.[3] Here, we present an experimental and theoretical study in order to investigate how the N-substitution and the change from para- to meta-dicyanomethylene substitution on carbazole-based biradicals affects their biradical character and thus, their tendency to act as useful motifs for DCC (see Figure 1).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Improved prediction of the optical properties in pi-conjugated polymers: the case of benzochalcogenodiazole-based copolymers with different heteroatom substitution

Donor−acceptor (D−A) approach to conjugated polymer design has become a widely used method for preparing conjugated polymers with narrow band gaps.1 One outstanding D−A polymer is poly(cyclopentadithiophene)benzothiadiazole, PCPDTBT (P1 in Figure 1), for which power conversion efficiencies in solar cells of 4.5-5.5% are reported.2 In this work, we use resonance Raman (RR) and density functional theory (DFT) calculations to investigate the tuning of the electronic and structural properties of cyclopentadithiophene-benzochalcogenodiazole D−A polymers, wherein a single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium to tellurium (Fig. 1).3 Sophisticated DFT calculations have been carried out using long-range corrected functionals, considering both tuned and default range-separation parameters, aiming at predicting their optical and charge transport properties. In addition, the nature of the electronic excitation is described by analyzing the enhancement pattern in the RR spectra using Raman excitation wavelengths coincident with the various transitions in the copolymers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

(−)-Istanbulin A

The title compound (systematic name: 9a-hydr­oxy-3,4a,5-trimethyl-4a,6,7,8a,9,9a-hexa­hydro-4H,5H-naphtho[2,3-b]furan-2,8-dione), C15H20O4, is a sesquiterpene lactone showing the typical eremophilanolide skeleton, which has been isolated from the plant Senecio candidans collected in the Chilean Magallanes region. The present study confirms the atomic connectivity assigned on the basis of 1H and 13C NMR spectroscopy, as well as the relative stereochemistry of the 4α-methyl,5α-methyl,8β-hydr­oxy,10β-H unit. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds involving the hydr­oxy group as donor and the oxo group as acceptor, giving chains along the a axis. The absolute structure was not determined because of the lack of suitable anomalous scatters

Síndrome de Mirizzi tipo V: manejo laparoscópico

Introduction: Mirizzi's syndrome is an infrequent complication of biliary lithiasic disease, with an incidence of less than 1% in developed countries, being even less frequent the type V variant. Current literature disagrees on the management of this condition, stating that laparoscopic surgery is not safe as a standard procedure. Clinical Case: We present the case of Mirizzi’s Syndrome in an 80-year-old man, which is referred to the emergency department for suspicion of sepsis of abdominal origin, with ultrasound study of cholelithiasis, pneumoobilia and dilation of the bile ducts. Retrograde endoscopic cholangiopancreatography was performed with technical impossibility for the mobilization and extraction of large-size stones, resorting to exploration through laparoscopic technique, obtaining satisfactory results. Conclusion: It is necessary to emphasize that the type of Mirizzi syndrome, the patient's characteristics and the surgeon's experience directly influence the treatment modality, its complications and/or success rates. In the present case, the experience of the main author in the management of minimally invasive procedures and the consideration of reducing the risk of complications such as infections in a fragile patient, were the factors that influenced the decision for laparoscopic intervention.Introducción: El Síndrome de Mirizzi es una complicación  infrecuente de la enfermedad litiásica biliar, con una incidencia menor al 1% en países desarrollados,  puede desarrollarse en cinco variantes, siendo  menos frecuente la variante tipo V. La literatura actual discrepa sobre el manejo de esta condición, afirmando que la cirugía laparoscópica no es segura como procedimiento estándar. Caso Clínico: Se presenta el caso de Síndrome de Mirizzi en un hombre de 80 años, que es remitido al departamento de urgencias por sospecha de sepsis de origen abdominal, con estudio ecográfico de colelitiasis, neumobilia y dilatación de las vías biliares. Se realizó Colangiopancreatografía retrógrada endoscópica con imposibilidad técnica para la movilización y extracción de los cálculos por gran tamaño, recurriéndose a exploración a través de técnica laparoscópica, obteniéndose resultados satisfactorios. Conclusión: Para tratar el  Síndrome de Mirizzi, es necesario considerar  las características del paciente y la experiencia del cirujano ya que ambos factores influyen directamente en la modalidad del tratamiento, sus complicaciones y tasas de éxito. En el presente caso, la experiencia del autor principal en el manejo de procedimientos mínimamente invasivos y la consideración de reducir el riesgo de complicaciones como infecciones en un paciente frágil, fueron los factores que influyeron para la decisión de intervención laparoscópica

Síndrome de Mirizzi tipo V: manejo laparoscópico

Introduction: Mirizzi's syndrome is an infrequent complication of biliary lithiasic disease, with an incidence of less than 1% in developed countries, being even less frequent the type V variant. Current literature disagrees on the management of this condition, stating that laparoscopic surgery is not safe as a standard procedure. Clinical Case: We present the case of Mirizzi’s Syndrome in an 80-year-old man, which is referred to the emergency department for suspicion of sepsis of abdominal origin, with ultrasound study of cholelithiasis, pneumoobilia and dilation of the bile ducts. Retrograde endoscopic cholangiopancreatography was performed with technical impossibility for the mobilization and extraction of large-size stones, resorting to exploration through laparoscopic technique, obtaining satisfactory results. Conclusion: It is necessary to emphasize that the type of Mirizzi syndrome, the patient's characteristics and the surgeon's experience directly influence the treatment modality, its complications and/or success rates. In the present case, the experience of the main author in the management of minimally invasive procedures and the consideration of reducing the risk of complications such as infections in a fragile patient, were the factors that influenced the decision for laparoscopic intervention.Introducción: El Síndrome de Mirizzi es una complicación  infrecuente de la enfermedad litiásica biliar, con una incidencia menor al 1% en países desarrollados,  puede desarrollarse en cinco variantes, siendo  menos frecuente la variante tipo V. La literatura actual discrepa sobre el manejo de esta condición, afirmando que la cirugía laparoscópica no es segura como procedimiento estándar. Caso Clínico: Se presenta el caso de Síndrome de Mirizzi en un hombre de 80 años, que es remitido al departamento de urgencias por sospecha de sepsis de origen abdominal, con estudio ecográfico de colelitiasis, neumobilia y dilatación de las vías biliares. Se realizó Colangiopancreatografía retrógrada endoscópica con imposibilidad técnica para la movilización y extracción de los cálculos por gran tamaño, recurriéndose a exploración a través de técnica laparoscópica, obteniéndose resultados satisfactorios. Conclusión: Para tratar el  Síndrome de Mirizzi, es necesario considerar  las características del paciente y la experiencia del cirujano ya que ambos factores influyen directamente en la modalidad del tratamiento, sus complicaciones y tasas de éxito. En el presente caso, la experiencia del autor principal en el manejo de procedimientos mínimamente invasivos y la consideración de reducir el riesgo de complicaciones como infecciones en un paciente frágil, fueron los factores que influyeron para la decisión de intervención laparoscópica

Simulation Studies on the Stability of the Vortex-Glass Order

The stability of the three-dimensional vortex-glass order in random type-II superconductors with point disorder is investigated by equilibrium Monte Carlo simulations based on a lattice XY model with a uniform field threading the system. It is found that the vortex-glass order, which stably exists in the absence of screening, is destroyed by the screenng effect, corroborating the previous finding based on the spatially isotropic gauge-glass model. Estimated critical exponents, however, deviate considerably from the values reported for the gauge-glass model.Comment: Minor modifications made, a few referenced added; to appear in J. Phys. Soc. Jpn. Vol.69 No.1 (2000

Síndrome de Mirizzi tipo V: manejo laparoscópico

Introduction: Mirizzi's syndrome is an infrequent complication of biliary lithiasic disease, with an incidence of less than 1% in developed countries, being even less frequent the type V variant. Current literature disagrees on the management of this condition, stating that laparoscopic surgery is not safe as a standard procedure. Clinical Case: We present the case of Mirizzi’s Syndrome in an 80-year-old man, which is referred to the emergency department for suspicion of sepsis of abdominal origin, with ultrasound study of cholelithiasis, pneumoobilia and dilation of the bile ducts. Retrograde endoscopic cholangiopancreatography was performed with technical impossibility for the mobilization and extraction of large-size stones, resorting to exploration through laparoscopic technique, obtaining satisfactory results. Conclusion: It is necessary to emphasize that the type of Mirizzi syndrome, the patient's characteristics and the surgeon's experience directly influence the treatment modality, its complications and/or success rates. In the present case, the experience of the main author in the management of minimally invasive procedures and the consideration of reducing the risk of complications such as infections in a fragile patient, were the factors that influenced the decision for laparoscopic intervention.Introducción: El Síndrome de Mirizzi es una complicación  infrecuente de la enfermedad litiásica biliar, con una incidencia menor al 1% en países desarrollados,  puede desarrollarse en cinco variantes, siendo  menos frecuente la variante tipo V. La literatura actual discrepa sobre el manejo de esta condición, afirmando que la cirugía laparoscópica no es segura como procedimiento estándar. Caso Clínico: Se presenta el caso de Síndrome de Mirizzi en un hombre de 80 años, que es remitido al departamento de urgencias por sospecha de sepsis de origen abdominal, con estudio ecográfico de colelitiasis, neumobilia y dilatación de las vías biliares. Se realizó Colangiopancreatografía retrógrada endoscópica con imposibilidad técnica para la movilización y extracción de los cálculos por gran tamaño, recurriéndose a exploración a través de técnica laparoscópica, obteniéndose resultados satisfactorios. Conclusión: Para tratar el  Síndrome de Mirizzi, es necesario considerar  las características del paciente y la experiencia del cirujano ya que ambos factores influyen directamente en la modalidad del tratamiento, sus complicaciones y tasas de éxito. En el presente caso, la experiencia del autor principal en el manejo de procedimientos mínimamente invasivos y la consideración de reducir el riesgo de complicaciones como infecciones en un paciente frágil, fueron los factores que influyeron para la decisión de intervención laparoscópica